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A diverse mid-Darriwilian trilobite fauna from the Table Cove Formation, western Newfoundland, has long been known on the basis of calcareous specimens from the west coast of the Great Northern Peninsula. Discovery of silicified faunas in localities on the east coast provides additional morphological information for previously known species, and also reveals the presence of multiple new genera and species. Many of these species are important, as they represent some of the earliest Laurentian members of the diversifying Whiterock Fauna, and seem phylogenetically near to the base of their respective clades. The concept of Sphaerexochinae is restricted to the genus Sphaerexochus itself, with the possible inclusion of Newfoundlandops n. gen. (type species N. karimae n. sp.), which shares with Sphaerexochus potential synapomorphies including the structure of the hypostome and the presence of fine granular sculpture on the librigenal border and field. Most of the Early and Middle Ordovician taxa with three pygidial segments previously classified as Sphaerexochinae by many authors are reassigned to Acanthoparyphinae on the basis of multiple putative synapomorphies. Other new cheirurid genera from the Table Cove Formation are the pilekiine Harebayaspis n. gen. (type species H. plurima n. sp.), and the deiphonine Mainbrookia n. gen. (type species M. becki n. sp.). Other species revised or described include the cheirurine Laneites polydorus (Billings, 1865), and the acanthoparyphines Cydonocephalus tiffanyae n. sp., Kawina stougei n. sp., and Kawina? sp.

Placoparina ? dravidicus (Reed, 1915) Fig. 13.2 1915 Cheirurus dravidicus; Reed, p. 48, pl. 8, fig. 12. Material. Holotype: pygidium from Lower Naungkangyi Beds (probable Darriwilian) at Man-shio, Fig. 13.2 (Reed, 1915, pl. 8, fig. 12), GSI 11559. Discussion. The species was described by Reed (1915) on the basis of one pygidium; a cast from the counterpart of the type specimen is illustrated here. Reed’s illustrations show the tips of the three pairs of pygidial spines. The anterior pair is not noticeably more strongly developed than the other two pairs, as it is in cheirurines, and the posterior pair is also prominent in P.? dravidicus. Lane (1971) showed that pygidia were the most informative sclerite in cheirurids, and it seems improbable that P. ? dravidicus is a cheirurine given its pygidial structure. Eccoptochile has a pygidium with three pairs of obtuse spines (type material of the type species in Horný & Bastl, 1970, pl. 14, fig. 1). The pygidium of Placoparina Whittard, 1940, is generally similar. However, the relatively obtuse lobes, and their marked fulcrum are more like those on Placoparina (Whittard, 1958) than Eccoptochile, and dravidicus is tentatively assigned herein to Placoparina. The identity of Reed’s species cannot confidently be resolved without further collections., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 340, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Reed, F. R. C. (1915) Supplementary Memoir on new Ordovician and Silurian fossils from the Northern Shan States. Palaeontologia Indica, New Series 6, 1 - 98.","Lane, P. D. (1971) British Cheiruridae (Trilobita). Monographs of the Palaeontographical Society, 530, 1 - 95.","Horny, R. & Bastl, F. (1970) Type specimen of fossils in the National Museum, Prague. Trilobita. National Museum, Prague, Prague, 354 pp.","Whittard, W. F. (1940) The Ordovician trilobite faunas of the Shelve-Corndon District, West Shropshire, Part 1. Annals and Magazine of Natural History, Series 11, 5, 153 - 172.","Whittard, W. F. (1958) The Ordovician trilobites of the Shelve inlier, west Shropshire. Monographs of the Palaeontographical Society, 1958, 71 - 116."]}

Yanhaoia wynnei (Reed, 1915) Figs 13.4-9 1915 Phacops (Pterygometopus) dagon; Reed, p. 53–54, pl. 9, fig. 3. 1915 Phacops (Pterygometopus) dagon var. wynnei; Reed, p. 54–55, pl. 9, figs 7–15. Material. Lectotype (selected herein): partial exoskeleton from Hwe Mawng, Fig. 13.8 (Reed, 1915, pl. 9, fig. 10), GSI 11576. Other material: incomplete cephalic shield from Hwe Mawng, Fig. 13.5 (Reed, 1915, pl. 9, fig. 7), GSI 11573; 2 incomplete cephalic shields from Mong Ha, Fig. 13.6 and unfigured (Reed, 1915, pl. 9, fig 11,8 respectively), GSI 11577, 11574 respectively; librigenae from Mong Ha, Nawng Yun, and Hwe Mawng (Reed, 1915, pl. 9, figs 9,13,14 respectively), GSI 11575, 11579, 11580 respectively;_pygidia from Hpawkyi and Nawng Yun, Fig. 13.7, 9 (Reed, 1915, pl. 9, figs 12,15) GSI 11578, 11581. All specimens from Hwe Mawng Beds (Katian) at Hpakhi, Hwe Mawng, Mong Ha, or Nawng Yun. Occurrence. Hwe Mawng Beds, type locality. Description. Reed’s (1915) general description can be supplemented by comments on particular features. The lectotype is distorted, but the cast shows the best surface detail. Other cephalic shields are internal moulds for the most part and as a result both the axial and glabellar furrows are deep and wide compared with their expression on the dorsal surface. The cephalic shield was originally somewhat less than twice as wide as long or narrower (Fig. 13.4). Three of the specimens displaying the glabella (Figs 13.4,6,8) show that the short S1 basal glabellar furrow is forked close to its base, and that the posterior fork outlines a basal lateral glabellar lobe –this is clearly seen on the lectotype and in Figs 13.4, 6 (right). S2 is gently forwardly–directed, and the sigmoid form of gently backwardly-directed S3 is best shown in Fig. 13.6. Certain species of Calyptaulax show a similar structure. The anterior cranidial border is shown on the lectotype and on the cranidium Fig. 13.4, where it is narrow and rim-like, especially medially, and defined by a shallow furrow. Eyes are very large, half (exsag.) cranidial length (sag.), the deeply-defined palpebral rims flipped upwards from the level of the intraocular cheeks. The number of dorso-ventral lens files is not precisely determinable but certainly exceeds twenty, on high standing eyes. The free cheek illustrated by Reed (1915, pl. 9, fig. 9) suggests about 15 lenses per dorso-ventral file. The lectotype clearly shows deeply and coarsely pitted sculpture on the intraocular cheeks. The same sculpture extends on to the lateral parts of the fixed cheeks, but more feebly. There is no evidence of a genal spine. The incomplete six thoracic segments on the lectotype show the same kind of sculpture anterior to the deep and narrow epifacetal pleural furrows. Well-preserved subtrapezoidal pygidium is best shown by cast from external mould (Fig. 13.9, right), 75% as long as wide. Eight (?faint ninth) axial rings, but internal mould (Fig. 13.7) would have displayed at least ten. Interpleural furrows much weaker than pleural furrows, defining six or seven ribs fading out on border, but again internal mould certainly shows more ribs extending to the posterior axial rings. Border is gently concave, most noticeably laterally. Posterior termination of pygidium behind axis shows a tendency to come to a median point. Discussion. Reed (1915) distinguished wynnei as a subspecies of his taxon Phacops (Pterygometopus) dagon from the Upper Naungkangyi Beds. Quite apart from their stratigraphical separation, the cranidium of dagon differs from that of wynnei in having a distinct and wider cephalic border (sag.), relatively wider basal part of the glabella, and the first glabellar furrow S1 has less distinct distal bifurcation. It is regarded as belonging to a different genus. Hence Pterygometopus dagon wynnei is here elevated to species rank, and not regarded as closely related to P. dagon dagon. On the other hand, wynnei is also different from chasmopine pterygometopids with typically inflated and enlarged lateral glabellar lobes. It more closely resembles genera such as Achatella, which, according to Swisher et al. (2016), is a Baltic/Laurentian clade, and one with smaller eyes and generally distinct tuberculate sculpture, unlike wynnei. The presence of three pairs of well-developed lateral glabellar furrows is a plesiomorphic character. Small lateral basal glabellar lobes which become eliminated in more advanced species is pterygometopid, and exceptionally large eyes are typical of several taxa. Although the type species of Yanhaoia is not completely known and is older, Y. wynnei does share with it a narrow glabella posteriorly, and particularly large eyes, and, given the other similarities between Burmese and SW Chinese taxa, is assigned provisionally to this genus pending a revision of the whole group., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on pages 341-342, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Reed, F. R. C. (1915) Supplementary Memoir on new Ordovician and Silurian fossils from the Northern Shan States. Palaeontologia Indica, New Series 6, 1 - 98.","Swisher, R. E., Westrop, S. R. & Amati, L. (2016) Systematics and biogeographical significance of the Upper Ordovician pterygometopine trilobite Achatella Delo, 1935. Journal of Paleontology, 90, 59 - 78. https: // doi. org / 10.1017 / jpa. 2015.71"]}

Dalmanitina ? dagon (Reed, 1915) Figs 13.10, 11 1915 Phacops (Pterygometopus) dagon; Reed, pl. 9, figs 1–6, non fig. 3. Material. Lectotype (selected herein): cephalic shield, original of Reed (1915) pl. 9, fig 1, GSI 11568. Pygidium, original of Reed (1915) pl. 9, fig. 5, GSI 11571. Upper Naungkangi Beds, Mangai. All specimens from Upper Naungkangyi Beds (Katian) at Man Ngai, northern Shan State. Discussion. As considered above, Reed (1915) described a variety of what he termed Phacops (Pterygometopus) dagon as var. wynnei, which is regarded herein as a different taxon. The material of the nominate species is limited, and we have not been able to cast some of the original specimens, as they are fragile. The robust largest cranidium is selected as lectotype. A smaller cephalon illustrated by Reed (1915, pl. 9 fig. 2; Fig. 13.10) shows a well-defined anterior border, which was likely also present on the lectotype, though obviously broken medially in that specimen. Such a border is atypical of Dalmanitina, and may possibly suggest such genera as Mucronaspis, but without knowledge of the rest of the exoskeleton we prefer a provisional allocation to the older established genus. This border is extremely narrow on wynnei. The glabella of dagon is comparatively transverse anteriorly, and the bifurcation of the S1 is not so marked. Another small? cephalon illustrated by Reed (1915, pl. 9, fig. 3) is more like wynnei and is excluded from dagon here. The generic assignment of D. ? dagon is equivocal, and the eyes are longer (exag.) than is typical for the dalmanitines according to Holloway (1981), a subfamily hard to delimit (Hammann & Leone, 2007). The species is placed provisionally in Dalmanitina pending a more comprehensive revision of Late Ordovician species., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on pages 342-343, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Reed, F. R. C. (1915) Supplementary Memoir on new Ordovician and Silurian fossils from the Northern Shan States. Palaeontologia Indica, New Series 6, 1 - 98.","Hammann, W. & Leone, F (2007) Trilobites from the post-Sardic (Upper Ordovician) sequence of southern Sardinia. Part 2. Beringeria, 38, 1 - 138."]}

“ Calymene” oldhami Reed, 1915 Figs 10.11, 12 1915 Calymene oldhami sp. nov. Reed; p. 47–48, pl. 8, figs 10,11. Material. Holotype: cranidium with partial thorax and hypostome in part and counterpart from Lower Naungkangyi Beds (probable Darriwilian) at Man-shio, Figs 10.11, 12 (Reed, 1915, pl. 8 figs 11,10), GSI 11557, 11558. Discussion. A single small cranidium was the basis for this species. Reed (1915) illustrated both part and counterpart of this specimen, and this is followed herein. However, the specimens have deteriorated since their original description. For example, the hypostome is quite clearly shown on Brock’s illustration (Reed, 1915, pl. 8, fig. 11) and displays the median fork consistent with calymenid affinities; this is no longer clearly shown. They are included here for completeness. It is not possible to give a more precise generic assignment to this species, which is best regarded as a nomen dubium., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 340, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Reed, F. R. C. (1915) Supplementary Memoir on new Ordovician and Silurian fossils from the Northern Shan States. Palaeontologia Indica, New Series 6, 1 - 98."]}

Neseuretinus birmanicus (Reed, 1906) Figs 12.9,11–15 Synonymy. See Turvey, 2005, p. 560; also Ghobadi Pour & Popov 2009 Material. Lectotype (selected Turvey, 2002, p. 560): cranidium from probable Lower Naungkangyi Beds (probable Darriwilian) at Kunkaw, Fig. 12.9 (Reed, 1906, pl. 5, fig. 27), GSI 8341. Additional material: pygidium from Lower Naungkangyi Beds (probable Darriwilian) at Loikok, Figs 12.14, 15 (Reed, 1915, pl. 8, fig. 5), GSI 11553; 2 cranidia from Upper Naungkangyi Beds (Katian) at Lilu (Reed, pl. 8, figs 1,4), GSI 11549, 11552 respectively; cranidium from Hwe Mawng Beds at Pa-hki (Reed,1915, pl. 8, figs 2), GSI 11550; pygidia from the Lower and Upper Naungkangyi Beds (Katian) at Lilu and Loi Kok (Reed, pl. 8, figs 3,5), GSI 11551, 11553 respectively. Material from new collections: crandidium, pygidium with partial thoracic segment, and pygidium from Pupiao Formation (Katian) at Pupiao, Figs 12.11–13, CMC 91532 –91534 respectively. Discussion. Turvey (2005) gave a full description of this species, and it is not necessary to reillustrate all Reed’s material in this work. The lectotype is refigured here for the record. Well-preserved articulated specimens from Iran attributed to N. birmanicus have been described by Ghobadi Pour & Popov (2009), who included several other species in their synonymy. As presently conceived, N. birmanicus has a long stratigraphic range. The type material is likely to come from the Lower Naungkangyi Beds and is probably Darriwilian in age, as is material from Loikok. This is the same age as the good specimens from Iran figured by Ghobadi Pour and Popov (2009). However, the other specimens in Reed (1915) refigured by Turvey (2005) are from the Upper Naungkangyi Beds and Katian in age. It does seem unlikely that a single species would have such an extensive stratigraphical range. Ghobadi Pour (written communication 2021) has pointed out that the Katian pygidia have eight pleural ribs, whereas Darriwilian examples from Iran and Myanmar have six ribs. If this is consistent, it does suggest that there are two taxa involved under the name birmanicus. Neseuretinus specimens from Uzbekistan figured by Kolobova (in Sokolov & Yolkin, 1978, pl. 27, figs. 1-5) under the name Calymenesun tingi were reassigned to Neseuretinus turcicus by Hammann & Leone (1997) and have six pygidial pleural ribs. There is also another poorly nown species from Afghanistan described by Wolfart (1970) (Neseuretinus malestanus) that may be an available name for the Katian species, with relevant Reed specimens illustrated by Turvey (2005). For present purposes we separate the Katian species from the Darriwilian type material as Neseuretinus aff. birmanicus pending a comparative treatment of all these taxa. Also figured are some additional specimens of Neseuretinus aff. brimanicus collected from the Pupiao Formation at the Pupiao section in Baoshan Prefecture, W. Yunnan by NCH in 1999. These specimens provide a connection between Katian strata in northern Shan State and western Yunnan. However, a cranidium from the Shihtien Formation attributed to N. birmanicus in Zhang et al. (2014, fig. 5.41E) differs from the type of N. birmanicus in having a more rectangular glabella and more anteriorly positioned palpebral lobes. The palaeogeographical distribution of Neseuretinus was also discussed by Turvey (2002) who noted its wide distribution across Ordovician Gondwana and inferred its probable phylogeny. GSI 11550 figured by Turvey (2005, pl. 2, fig. 9) is reported as being from the Hwe Mawng Beds, and appears identical to specimens from the Upper Naungkangyi Beds., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 338, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Reed, F. R. C. (1906) The Lower Paleozoic fossils of the Northern Shan States, Upper Burma. Palaeontologia Indica, New Series 2, 1 - 154.","Turvey, S. T. (2005) Reedocalymenine trilobites from the Ordovician of central and eastern Asia, and a review of species assigned to Neseuretus. Palaeontology, 48, 549 - 575. https: // doi. org / 10.1111 / j. 1475 - 4983.2005.00469. x","Ghobadi Pour, M. & Popov, L. E. (2009) First report on the occurrence of Neseuretinus and Ovalocephalus in the Middle Ordovician of Iran. Acta Palaeontologica Polonica, 54, 125 - 133. https: // doi. org / 10.4202 / app. 2009.0113","Turvey, S. T. (2002) Phylogeny of the Reedocalymeninae (Trilobita): implications for Early Ordovician biogeography of Gondwana. In: Crame, A. J. & Owen, A. W. (Eds.), Palaeobiogeography and biodiversity change: the Ordovician and Mesozoic - Cenozoic radiations. Geological Society of London Special Publications, 194, 53 - 68.","Reed, F. R. C. (1915) Supplementary Memoir on new Ordovician and Silurian fossils from the Northern Shan States. Palaeontologia Indica, New Series 6, 1 - 98.","Sokolov, B. S. & Yolkin, E. A. (Eds.) (1978) Trilobita. In: Upper Ordovician and Silurian of the Sayan Altai region of Tien Shan. Trudy Instituta Geologii I Geofiziki, 387, pp. 126 - 141. [in Russian]","Hammann, W. & Leone, F. (1997) Trilobites from the post-Sardic (Upper Ordovician) sequence of southern Sardinia. Part 1. Beringeria, 20, 1 - 217.","Wolfart, R. (1970) Fauna, Stratigraphie und Palaogeographie des Ordoviciums in Afghanistan. Geologische Jahrbuch, 89, 1 - 169.","Zhang, Y. - D., Wang, Y., Zhan, R. - B., Fan, J. - X., Zhou, Z. - Q & Fang, X. (2014) Ordovician and Silurian Stratigraphy and Palaeontology of Yunnan, Southwest China. A guide to the field excursion across the South China, Indochina and Sibumasu. IGCP Project 591. Science Press, Beijing, 138 pp."]}

Pliomerina Chugaeva, 1956 Type species. Pliomera martellii, Reed, 1917, original designation. Discussion. The type species of Pliomerina is part of Reed’s collection, but this is known only from the cranidium, redescribed here. Silicified and complete material from Australia described by Webby (1971, p. 614) is doubtless congeneric with the Myanmar type species, and provides a fuller diagnosis than is possible from the type material alone. Webby (1971) pointed out that Pliomerina is widely distributed across Australasia and adjacent territories, extending from Kazakhstan in the north to New South Wales, Australia, in the south, with additional occurrences on the South China plate, Sibumasu and Korea, i.e. palaeotropical Gondwana on current palaeocontinental reconstructions. Webby preferred the term “ Pliomerina fauna” to cover this Ordovician biogeographic region to “ Encrinurella fauna” coined by Whittington & Hughes (1972), though they embrace a similar geographic compass. Zhou & Zhen (2008) record the genus through much of the post-Tremadocian Ordovician of China, including northeastern Chinese and Tibetan occurrences., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 330, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Chugaeva, M. N. (1956) New trilobite genera from the Middle and Upper Ordovician of southern Kazakhstan. Doklady Akademia Nauk SSSR, 111 (6), 1336 - 1339. [in Russian]","Reed, F. R. C. (1917) Ordovician and Silurian fossils from Yun-nan. Palaeontologia Indica, 6 (3), 1 - 69.","Webby, B. D. E. (1971) The Ordovician trilobite Pliomerina Chugaeva from the Ordovician of New South Wales. Palaeontology, 14, 612 - 622.","Whittington, H. B. & Hughes, C. P. (1972) Ordovician geography and faunal provinces. Philosophical Transactions of the Royal Society of London, Series B, 263, 236 - 276. https: // doi. org / 10.1098 / rstb. 1972.0001","Zhou, Z. - Y. & Zhen, Y. - Y. (Eds.) (2008) Trilobite Record of China. Science Press, Beijing, 20 pp."]}

Ovalocephalus sp. Figs 10.10, 13 pars 1915 Calymene (Pharostoma) liluensis Reed; Reed, pl. 8, fig. 9. ? 1915 Pliomera (Encrinurella) insangensis Reed; Reed, p. 8, fig. 21. Material. Pygidium from the Li-Lu Formation (Upper Naungkangyi Beds; Katian) at Nam Tu above Lilu, northern Shan State, Myanmar, Fig. 10.10 (Reed, 1915, pl. 8, fig. 9), GSI 11556; Cranidium from unknown northern Shan State horizon and locality, Fig. 10.13, unregistered and not previously figured by Reed. Description. A single example of a pygidium is twice as wide as long, and with low transverse convexity.Anterior transverse width of the axis is approximately equal (tr.) to the anterior part of the pleural lobe. Axis tapers, but is effaced posteriorly, and rings low and band-like, three clearly defined by gently forwardly arched ring furrows that continue on to pleural fields. Fourth ring furrow faint, and narrow; no defined terminal piece. Pleural ribs: two welldefined gently downsloping to margin, the first probably slightly exceeding it, with deep pleural furrows between; third rib incompletely defined by shallow furrow that does not extend to margin. Narrow and convex articulating ridge visible on left hand side. The external mould of a small cranidium was also discovered and cast while investigating the Reed collections, but we can find no indication that Reed examined it. The preservation is similar to that of other specimens from the “Upper Naungkangyi Beds” from northern Shan State and it is figured herein for the record Fig. 10.13). Discussion. This pygidium described above is typical of those belonging to the genus Ovalocephalus Koroleva, and Reed (1915) was mistaken in associating it with the calymenoid cranidium on his pl. 8, figs 6,7. Zhou et al. (2010) reviewed the synonymy, taxonomy and included species of Ovalocephalus Koroleva. The single pygidium figured here is important as the first record from the Reed collections of a genus that is widely recorded in the Ordovician of eastern Asia and certain Kazakh terranes, and can be regarded as an indicator of subtropical Gondwana and peri-Gondwanan terranes until the late Katian, when it migrated to western Gondwana in response to what has been claimed as a short-lived episode of global warming (Fortey & Cocks, 2005). The pygidium is not determinable to species, but is unlike the stratigraphically earlier species reviewed in Zhou et al. (2010), which have noticeably posteriorly-turned pleural ribs. As an internal mould, the pleural furrows appear wider than in many species figured from better material. O. kanlingensis Zhang, 1981 (Darriwilian-Sandbian, material figured in Zhou et al., 2010) has similarly arranged pleural ribs, although the Reed material is inadequate for confident determination. As noted above, two specimens attributed to Encrinurella insangensis by Reed (1915) are excluded from that species. The cranidium (Fig. 10.5) shows inflated posterolateral glabellar lobes, which appear to be part of the occipital ring. They resemble the circular basal glabellar lobes of Ovalocephalus, but these are pre-occipital (Zhou et al., 2010). It is conceivable that the lobes on the Burmese specimen have migrated backwards to a (pseudo) occipital position. There are indications on the internal mould of the glabella of large tubercles, which were presumably expressed on the dorsal surface. A partial thorax (Reed, 1915, pl. 8 fig. 21; Fig. 10.8) displays lateral inflated areas on the axial rings, which suggests it could belong with the cranidium. While excluded from Encrinurella, these specimens are possibly closer to Ovalocephalus, although if coarse tubercles are present it is unlike other species of that genus. The unlocalised cranidium (Fig. 10.13) is more consistent with similarly preserved specimens of Ovalocephalus, including the type species O. tetrasulcatus Kielan, 1960. However, Zhou et al. (2010) illustrated a number of other late Ordovician Ovalocephalus species with elongate (sag.) glabellas with short glabellar furrows and our internal mould here is inadequate for precise identification. It is conceivable that it is the cranidium appropriate to Reed Ovalocephalus sp. pygidium but we cannot prove this without further collections., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on pages 335-336, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Reed, F. R. C. (1915) Supplementary Memoir on new Ordovician and Silurian fossils from the Northern Shan States. Palaeontologia Indica, New Series 6, 1 - 98.","Zhou, Z. - Y., Yuan, W. - W. & Zhou, Z. - Q. (2010) Evolutional trends and palaeobiogeography of the Ordovician trilobite Ovalocephalus Koroleva. Proceedings of the Royal Society of London B, 277, 259 - 266. https: // doi. org / 10.1098 / rspb. 2009.0133","Fortey, R. A. & Cocks, L. R. M. (2005) Late Ordovician global warming - the Boda event. Geology, 33 (5), 405 - 408. https: // doi. org / 10.1130 / G 21180.1","Zhang, T. - R. (1981) Trilobita. In: Geological Surveying Team of Xinjiang Bureau of Geology (Ed.), Palaeontological Atlas of Northwestern China, Xinjiang volume (Late Proterozoic - Early Palaeozoic). Geological Publishing House, Beijing, pp. 134 - 213. [in Chinese]","Kielan, Z. (1960) Upper Ordovician trilobites from Poland and some related forms from Bohemia and Scandinavia. Acta Palaeontologica Polonica, 11, 1 - 191."]}

Yanhaoia Zhou, Yuan & Zhou, 1998 Type species. Pterygometopus huayinshanensis Lu, 1975, Middle Ordovician, Neichiashan Series, Sichuan, original designation. Remarks. The generic classification of pterygometopids is not yet in a stable state. The species described below is placed in Yanhaoia because of its unusually large eyes combined with a relatively narrow axis., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 341, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Zhou, Z. - Y., Zhou, T. - R. & Yuan, W. - W. (1998) Ordovician trilobites from the upper Qiulitag Group, western Tarim, Xinjiang, northwest China. Acta Palaeontologica Sinica, 37 (3), 269 - 282.","Lu, Y. - H. (1975) Ordovician trilobite faunas of central and southwestern China. Palaeontologia Sinica, New Series B, 11, 1 - 453."]}

Sphaerocoryphe sp. Fig. 13.3 1906 Sphaerocoryphe sp. indet. Reed, p. 77, pl. 5, fig. 26. Material. Cranidium from Upper Naungkangyi Beds (Katian) at Insang, northern Shan State, Fig. 13.3 (Reed, 1906, pl. 5, fig. 26), GSI 8340. Discussion. A single and diminutive cranidium from the northern part of the Shan State was fully described by Reed (1906) and is refigured here for reference. The assignment to Sphaerocoryphe is supported, although the material is inadequate for specific comparison. Generally similar internal moulds have been figured from other Upper Ordovician strata (e.g. Dean, 1971)., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 341, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Reed, F. R. C. (1906) The Lower Paleozoic fossils of the Northern Shan States, Upper Burma. Palaeontologia Indica, New Series 2, 1 - 154.","Dean, W. T. (1971) The trilobites of the Chair of Kildare Limestone (upper Ordovician) of eastern Ireland. Part 1. Monographs of the Palaeontographical Society, 531, 1 - 60."]}

Pliomerina martellii (Reed, 1917) Fig. 10.7 1917 Pliomera martellii; Reed, 1917, p. 55 –56, pl. 8, figs 15,16. Material. Holotype: cranidium from Shihtien Formation (Darriwilian) of Pupiao, Fig. 10.7 (Reed, 1917, pl. 8, figs 15,16) GSI 11915, Pupiao, western Yunnan, southwestern China. Description. Cranidium twice as wide as long. Glabella with low transverse convexity, maximum inflation across frontal lobe, greatest width at L3 is 1.3 times that across occipital ring, and slightly less than sagittal length. Anterior outline of glabella at cranidial margin is gently and evenly arcuate about the mid-line. Deep glabellar furrows extend less than one-third across glabella: S1 slightly curving backwards, S2 hardly so, and S3 distinctly inward-backwardly directed making an angle of about 30 degrees to the transverse line. Since this specimen is not a true dorsal surface the furrows may well have been longer and narrower on the exterior surface. The latter is undoubtedly also true of the deep and wide axial furrows that expand in width towards the anterolateral glabellar corners. Of glabellar lobes L3 is most inflated and widens abaxially; its greatest width (exsag.) is twice that of narrow L1 and 1.5 that of L2. Occipital furrow curves forwards in a broad arc medially, such that the occipital ring is widest in its central two-thirds. The anterior cranidial border is developed as a narrow ridge anterolaterally, but narrows and merges with the frontal lobe of the glabella adaxially. Silicified material figured by Webby (1971) shows that it remains just distinct from the glabella on the exterior surface but this is not expressed on the internal mould. Fixed cheeks three-quarters as wide (tr.) as maximum width of glabella, narrow (exsag.) posterior limb bisected by deep, wide border furrow (as preserved). Medium sized palpebral lobe extends back as far as L2, the area inside it narrow (tr.) and inflated. There is some evidence of a reticulum in this area. Discussion. Reed (1917, p. 56) referred to the type species being “represented by only two head-shields showing the cast and impression” and Webby (1971, p. 614) in turn referred to “two incomplete cranidia”. The type material consists of a single individual cranidium in part and counterpart, as Reed probably implied. Although it is preserved in full relief most of its features suggest that we are seeing the internal surface of this cranidium, and this should be taken into account in comparing with other species assigned to Pliomerina. Nonetheless, despite the lack of the associated pygidium from the type locality, with its characteristic well-defined elongate terminal piece, the species assigned to Pliomerina by Chugaeva (1958), Webby (1971) and listed in Zhou & Zhen (2008) form a tight group. A squat glabella with some lateral inflation of L3 is typical. However, P. tashanensis Lee, 2013, from Jiangxe Province, China, has an elongate glabella with somewhat effaced furrows, no lateral prominence of L3, and the pygidial terminal piece is not inflated; it is not typical of the genus. Cranidia of P. australis, Webby (from Australia) of similar size to the holotype of P. martellii (e.g. Webby, 1971, pl. 115, fig. 1) have a more deeply arcuate or parabolic outline of the frontal glabellar lobe, although smaller individuals like the holotype (Webby, 1971, pl. 114, figs 2-7) are more similar to P. martellii in this regard. However, the fixed cheeks are narrower (tr.) and the inflation of L3 more marked. Of three Katian species from Kazakhstan described by Chugaeva (1958) P. dulanensis is probably most similar to P. martellii, although its glabellar furrows are longer and more curved forwards. Possibly the most similar species to P. martellii is P. serrata described by Zhou & Zhou (2006) from Katian strata in Inner Mongolia; it may have longer glabellar furrows. An ‘outlier’ of the genus in Argentina (Edgecombe et al., 1999) provides good evidence that a segment of the Precordillera was part of Gondwana by the later Ordovician. It should be noted that Reed (1917) reported this species from several localities, but this is not reflected in the collections., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 331, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Reed, F. R. C. (1917) Ordovician and Silurian fossils from Yun-nan. Palaeontologia Indica, 6 (3), 1 - 69.","Webby, B. D. E. (1971) The Ordovician trilobite Pliomerina Chugaeva from the Ordovician of New South Wales. Palaeontology, 14, 612 - 622.","Chugaeva, M. N. (1958) Trilobites of the Ordovician of the Chu-Ili mountains. Ordovician of Kazakhstan 3. Trudy Geologicheskogo Instituta, 9, 1 - 138, 111 pls. [in Russian]","Zhou, Z. - Y. & Zhen, Y. - Y. (Eds.) (2008) Trilobite Record of China. Science Press, Beijing, 20 pp.","Lee, D. C. (2013) Late Ordovician trilobites from the Xiazhen Formation in Zhuzhai, Jiangxi Province, China. Acta Palaeontologica Polonica, 58 (4), 855 - 882. https: // doi. org / 10.4202 / app. 2010.0036","Zhou, Z. - Q. & Zhou, Z. - Y. (2006) Late Ordovician trilobites from the Zhusilenghaierhan area, Ejin Banner, western Inner Mongolia, China. Memoirs of the Association of Australasian Palaeontologists, 32, 383 - 411.","Edgecombe, G. D., Chatterton, B. D. E., Vacarri, N. E. & Waisfeld, B. G. (1999) Ordovician pliomerid and prosopiscid trilobites from Argentina. Journal of Paleontology, 73, 1144 - 1154. https: // doi. org / 10.1017 / S 0022336000031036"]}

Prionocheilus liluensis (Reed, 1915) Fig. 10.9 1915 Calymene (Pharostoma) liluensis; Reed, p. 4647, pl. 8, figs 6, 7, non pl. 8, fig. 9. Material. Holotype. Cranidium GSI 11554. Reed (1915, p. 47) did not associate the pygidium he figured with confidence, and it is therefore not to be regarded as one of the type series. Since this pygidium is that of an Ovalocephalus sp. (above) the cranidium is the only type specimen available for holotype. Reed illustrated part and counterpart of this specimen. Upper Naugkangyi Beds (Katian). Lilu right bank of Nam Tu, path to Manping. northern Shan State. Description. The external mould of the holotype is illustrated herein, and is reasonably well-preserved, although the tip of the fixed cheek is not present. Glabella occupies three-quarters of cranidial length (excluding occipital ring), and is as wide as long; occipital ring 25% total glabellar length. Glabella best preserved on right side showing convex flanks narrowing forwards to broadly arcuate front. Deep S1 with outer end at three-eighths cranidial length, curving inwards but fading well before occipital furrow, distally not quite becoming exsag. S2 follows in line with inner part of S1, and shallower, its anterior termination just behind a prominent anterior pit at the end of the axial furrow. L1 is twice as wide and twice as long as L2, and both somewhat inflated. Occipital ring well defined, narrows laterally, and carries a prominent circular median tubercle. Preglabellar field as wide (sag.) as border in front near midline, and widens towards corner of glabella. Palpebral lobe situated about 40% of the distance across the adjacent glabella, and of similar length (exsag.) to preglabellar field (sag.). Eye ridges strong and convex, directed back at about 60 degrees to sag. line.Anterior border furrow of even, moderate depth along its length. Border hardly convex and gently bowed forwards. Posterior border furrow as deep as axial furrows, and posterior section of fixed cheek presumably broadly triangular. Facial sutures diverge at a low angle in a convex curve in front of the palpebral lobes and at a high angle behind. Much of the dorsal surface is covered by fine tubercles, which appear coarser and sparser immediately in front of the preglabellar furrow and on the postocular fixed cheeks. A cranidium described by Kolobova (in Sokolov & Yolkin,1978, pl. 27, fig. 7) under the name Pharostoma inermis from the Upper Ordovician of Tien Shan is very like that of Prionocheilus liluensis, although it apparently has coarser tubercles on the dorsal surface., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 336, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Reed, F. R. C. (1915) Supplementary Memoir on new Ordovician and Silurian fossils from the Northern Shan States. Palaeontologia Indica, New Series 6, 1 - 98.","Sokolov, B. S. & Yolkin, E. A. (Eds.) (1978) Trilobita. In: Upper Ordovician and Silurian of the Sayan Altai region of Tien Shan. Trudy Instituta Geologii I Geofiziki, 387, pp. 126 - 141. [in Russian]"]}

Reedocalymene Kobayashi, 1951 Type species. Calymene unicornis Reed, 1917, Pupaio Formation, Yunnan, original designation. Discussion. Reed’s (1917) species is the nominated type species of Reedocalymene, although Lu (1975) described much better preserved material of the same genus. In a cladistic analysis of the Subfamily Reedocalymeninae Turvey (2002) showed that Reedocalymene and Calymenesun Kobayashi, 1951 are closely related. Lu (1975, p. 448) had noted this previously, and provided some distinguishing characters, supplemented further by Peng et al. (2000). However, some of these are contradictory. Lu (1975, p. 447) stated of Calymenesun that “the pygidium is quite different from all others of the Calymenids [sic] in having a very narrow border.” On p. 448 he states (of similarity between the two genera) that they share “a broad border on the pygidium”. He stated also that an important feature is the shape of the glabella which is claimed as “semioval” in Reedocalymene, as it is on R. expansa Yi (see Lu, 1975, pl. 46, fig. 4). However, the lectotype of R. unicornis shows a wider part of the glabella at the level of the basal lobes, which is actually more like that of the type species of Calymenesun, C. tingi Sun (Lu, 1975, pl. 46, figs 9,12). As discussed by Peng et al. (2000) the distinction between the two genera, both erected by Kobayashi (1951), is not clearcut, and they may eventually be synonymized. We follow these authors in recognizing the two genera pro tem., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 337, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Kobayashi, T. (1951) On the Ordovician trilobites in central China. Journal of the Faculty of Science Imperial University of Tokyo, Section II, Geology, 8, 1 - 87.","Reed, F. R. C. (1917) Ordovician and Silurian fossils from Yun-nan. Palaeontologia Indica, 6 (3), 1 - 69.","Lu, Y. - H. (1975) Ordovician trilobite faunas of central and southwestern China. Palaeontologia Sinica, New Series B, 11, 1 - 453.","Turvey, S. T. (2002) Phylogeny of the Reedocalymeninae (Trilobita): implications for Early Ordovician biogeography of Gondwana. In: Crame, A. J. & Owen, A. W. (Eds.), Palaeobiogeography and biodiversity change: the Ordovician and Mesozoic - Cenozoic radiations. Geological Society of London Special Publications, 194, 53 - 68.","Peng, S. - C., Lin, T. - R. & Li, Y. (2000) Notes on the genus Reedocalymene Kobayashi, 1951 (Trilobita, Ordovician). Acta Palaeontologica Sinica, 39, 63 - 75."]}

Dalmanitina Reed, 1905 Type species. Phacops socialis Barrande, 1846, Letná Formation (Berounian) Czech Republic, Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 342, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Barrande, J. (1846) Nouveaux trilobites. Notice preliminaire sur le systeme Silurien et les Trilobites de Boheme, Praha, 40 pp."]}

Neseuretinus Dean, 1967 Type species. Neseuretinus turcicus Dean, 1967, Sandbian, Bedinan Formation, Turkey, original designation., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 338, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Dean, W. T. (1967) The correlation and trilobite fauna of the Bedinan Formation (Ordovician) in south-eastern Turkey. Bulletin of the British Museum (Natural History), Geology, 15, 83 - 123."]}

Reedocalymene unicornis (Reed, 1917) Figs 12.1–6, 8, 10 1917 Calymene unicornis sp. nov.; Reed p. 52–54, pl. 8, figs 10–13. 1951 Reedocalymene unicornis (Reed, 1917); Kobayashi, p. 45, pl. 4, figs 12–14. 1975 Reedocalymene unicornis (Reed, 1917); Lu, p. 447. 2002 Reedocalymene unicornis (Reed, 1917); Turvey, p. 55. 2005 Reedocalymene unicornis (Reed, 1917) Turvey, p. 550. Material. Lectotype (selected by Turvey, 2005): damaged cephalon, Figs 12.1-3 (Reed, 1917, pl. 8, fig. 10), GSI 11913. Additional type material: cephalic fragments, Figs 12.5 /8 and 12.10/6 (Reed, 1917, pl. 8, figs 12,11 respectively), GSI 11912; pygidium, Fig. 12.4 (Reed, 1917, pl. 8, fig. 13), GSI 11911? All material from the Shihtien Formation (Darriwilian) at Pupiao, western Yunnan. Discussion. Reed (1917) described the limited material of this species in some detail, and new cast material does not greatly enhance our knowledge. The lectotype is more distorted than Brock’s original drawing suggests, and the upward curvature of the anterior pro/jection shown by Reed (1917, pl. 8, fig. 10a, GSI 11913) may have been exaggerated by this. However, the comparatively laterally expanded L1 on the glabella is probably a real feature, which is not so clear on the original drawing. This differs from other species assigned to the genus by Lu (1975) that have a uniformly deeply parabolic glabellar outline. In this respect R. unicornis more closely resembles species that have been assigned to Calymenesun and Vietnamia (see Turvey, 2002). However, it is possible that deformation may have contributed to this distinction. A very incomplete cranidium shows the outline of the posterior fixed cheek. A backwardly displaced free cheek with a narrow border is best displayed on Reed’s pl. 8, fig. 11; we have not been able to cast this specimen, nor the only example of a pygidium (Reed, 1917, pl. 8, fig. 13) reproduced here. The imperfect thorax and pygidium from Pupiao figured by Reed (1917, pl. 8, fig. 14) is refigured here (Fig. 12.7). It is likely to belong to a reedocalymenine, and possibly to Reedocalymene rather than Neseuretinus. However, the pygidial pleural ribs appear to be more pronounced than is the case with the pygidium assigned with more certainty to R. unicornis by Reed (1917, pl. 8, fig.13), and its assignment must remain uncertain., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 337, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Reed, F. R. C. (1917) Ordovician and Silurian fossils from Yun-nan. Palaeontologia Indica, 6 (3), 1 - 69.","Turvey, S. T. (2005) Reedocalymenine trilobites from the Ordovician of central and eastern Asia, and a review of species assigned to Neseuretus. Palaeontology, 48, 549 - 575. https: // doi. org / 10.1111 / j. 1475 - 4983.2005.00469. x","Lu, Y. - H. (1975) Ordovician trilobite faunas of central and southwestern China. Palaeontologia Sinica, New Series B, 11, 1 - 453.","Turvey, S. T. (2002) Phylogeny of the Reedocalymeninae (Trilobita): implications for Early Ordovician biogeography of Gondwana. In: Crame, A. J. & Owen, A. W. (Eds.), Palaeobiogeography and biodiversity change: the Ordovician and Mesozoic - Cenozoic radiations. Geological Society of London Special Publications, 194, 53 - 68."]}

Hadromeros Lane, 1971 Type species. Cheirurus keisleyensis Reed, 1896. Keisley Limestone (Katian) Northern England., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 340, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Lane, P. D. (1971) British Cheiruridae (Trilobita). Monographs of the Palaeontographical Society, 530, 1 - 95.","Reed, F. R. C. (1896) The fauna of the Keisley Limestone, Part 1. Quarterly Journal of the Geological Society of London, 52, 407 - 437."]}

Placoparina Whittard, 1940 Type species. Cryphaeus sedgwickii M’Coy, 1849, Middle Ordovician, Builth, South Wales, U.K., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 340, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Whittard, W. F. (1940) The Ordovician trilobite faunas of the Shelve-Corndon District, West Shropshire, Part 1. Annals and Magazine of Natural History, Series 11, 5, 153 - 172."]}

Encrinurella insangensis (Reed, 1906) Fig. 11 1906 Pliomera insangensis sp. nov.; Reed, p. 74–76, pl. 5, figs 19–25. 1915 Pliomera (Encrinurella) insangensis Reed; Reed, p. 50–51, pl. 8, figs 15, 16, 18–20; non figs 17, 21. cf. 1998 Encrinurella sp.; Fortey & Cocks, fig. 3N. Material. Lectotype (selected herein): cranidium from Hweyawt, Fig. 11.9 (Reed, 1906, pl. 5, figs 21,22), GSI 8335. Additional type material: cephalon with hypostome and pygidium from Hweyawt, Fig. 11.10 (Reed, 1906, pl. 5, figs 19, 23), GSI 8334; pygidium from Insang, Fig. 11.7 (Reed, 1906, pl. 5, fig. 20), GSI 8336; cranidium from Kunlein, Fig. 11.4 (Reed, 1906, pl. 5, fig. 24), GSI 8338; partial thorax from Ledet, Fig. 11.8 (Reed, 1906, pl. 5, fig. 25), GSI 8339.Additional material: cephalic shield from Hweyawt, Fig. 11.1 (Reed, 1915, pl. 8, fig. 16), GSI 11562; cephalic shield from Man Ngai, Fig. 11.2 (Reed, 1915, pl. 8, fig. 15), GSI 11561; cephalic shield from Makmongshai, Fig. 11.3 (Reed, 1915, pl. 8, fig. 18), GSI 11564; 2 pygidia from Man Ngai, Figs 11.5, 6 (Reed, 1915, pl. 8, figs 19,20 respectively), GSI 11565, 11566 respectively. All material from the Li-Lu Foramtion (Upper Naungkangyi Beds; Katian) at Hweyawt, Insang, Kunlein, Ledet, Makmongshai, or Man Ngai. Description. The lectotype is distorted, and even with attempted retrodeformation it is not entirely symmetrical. Undistorted cephalic shield from Reed’s later collection twice as wide as long, with maximum glabellar width across frontal lobe slightly exceeding that across genal area. A good cephalic shield (Fig. 11.3) is somewhat flattened and is relatively slightly wider across the frontal lobe, but there is probably still some transverse extension on this specimen, which also has more divergent axial furrows. The general resemblance between most of the specimens in different preservational states is still sufficient to suggest that one species is involved (but see comments below). Forward expansion of glabella is ten to fifteen degrees as measured to sagittal line on good material. Glabellar furrows short and deep, and with characteristic form: S1 gently concave forwards, S2 transverse or nearly so, while S3 is distinctly convex forwards, apostrophe shaped. Glabellar lobes accordingly vary in shape, with L1 very narrow (exsag.) especially laterally near axial furrow, L2 subrectangular, nearly twice as wide (exsag.) as L1, L3 longer again, more rounded, and appearing slightly inflated. Occipital ring extends laterally as far as, or slightly beyond L1, where it is noticeably narrower than in its median two-thirds. Occipital furrow curves forwards over this part, laterally deepening in line with glabellar furrows. Dorsal furrows are deep, including the axial furrows, but this is because the figured specimens are mostly internal moulds: the cast from the dorsal surface (Fig. 11.3) shows narrower furrows in general. This specimen also shows the posterior cranidial border most faithfully: gently convex, and hardly widening laterally, defined by deep but narrow border furrow. The border furrow is much exaggerated on the internal mould and the border appears narrower and more convex. Prominent semicircular palpebral lobes are located opposite L3 at about one quarter of the transverse width of the adjacent glabella, the eye lobe as a whole standing proud and about one quarter length (exsag.) of glabella in front of occipital ring. Cheeks inside palpebral lobes gently convex, as also behind the eye lobe. Postocular cheek triangular, more or less bisected by the posterior border furrow. Course of facial suture best seen on Fig. 11.10, showing anterior branch running near to the axial furrow and curving anteriorly closely around the frontal lobe of the glabella, outlining a narrow cranidial border there; posterior branch diverges behind the eye and runs to genal angle. One of Reed’s (1906) specimens (Fig. 11.10) has the glabella broken to reveal the outline of the hypostome beneath. It has a rounded-triangular outline tapering posteriorly and surrounded by a narrow and convex border. There is a suggestion of marginal denticles, especially close to the midline. The narrow free cheek extends forwards in a spine-like way to form the narrow border in front of the glabella. In dorsal view the wide, outward-sloping lateral cranidial border is dominant, outlined by a deep and wide marginal furrow. The convex eye is elevated on an eye socle which is defined at the base by a furrow running parallel to the border furrow, though half the width. Between this furrow and the border furrow an elevated and convex ridge is parallel to the lateral border. An incomplete thorax of eight segments is plausibly associated (Fig. 11.8) (compare with that of Encrinurella tetrasulcata Ju in Tripp et al., 1989, fig. 14k) showing convex axial rings of equal width having a small anterior forward turn like that on the occipital ring. Very prominent half rings are almost as long (sag.) as the axial rings themselves. Posterior pleural bands of similar width (exsag.) and convexity to axial rings, their outer halves steeply downturned to blunt tips. Anterior pleural bands very narrow (exsag.) depressed below level of posterior bands from which they are separated by transverse furrow extending as far as the pleural articulation. Pygidium has pleural ribs of similar form to thorax anteriorly and is twice as wide long, or somewhat longer; none is perfectly preserved. Four (? five) axial rings of decreasing width and length on gently tapering axis; terminal piece not clearly seen, but presumably very small and triangular. Five pairs of bluntly tipped pleural ribs turned downwards marginally, and progressively posteriorly directed, the rear pair behind the axis and running more or less exsagitally. Discussion. We are obliged to select a lectotype from the Reed (1906) collection even though less distorted examples are present in the 1915 collection. The cranidium figured here as Fig. 11.9, original of Reed 1906, pl. 5, fig. 22, is selected, numbered GSI 8335, which has the advantage of an associated pygidium and partial cephalon showing the eye lobe. The type material from Reed (1906) belongs to the single species Encrinurella insangensis, and most of the material he figured in 1915 can be confidently assigned to the same species. However, the internal mould of a cranidium figured here in Fig. 10.5, original of Reed (1915, pl. 8, fig. 17) differs from that of E. insangensis in several respects, notably in having wider glabellar furrows, smaller L1, and indications of coarse tubercles upon it, which may have been prominent on the dorsal surface. It also shows development of inflated circular lobes at the ends of the occipital ring. These seem to be real features rather than artifacts of preservation. The latter feature may relate to a partial thorax (Fig. 10.8) that also displays inflated lobes at the ends of the thoracic axial rings, with a convex lobe also on the proximal parts of the pleural bands. This thorax clearly belongs to a different species from the thorax of E. insangensis in Fig. 11.8. These specimens are both excluded from E. insangensis. The cranidium is very tentatively recorded here as Ovalocephalus ? sp. indet.; the thorax may also belong to the same species., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on pages 333-335, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Reed, F. R. C. (1906) The Lower Paleozoic fossils of the Northern Shan States, Upper Burma. Palaeontologia Indica, New Series 2, 1 - 154.","Reed, F. R. C. (1915) Supplementary Memoir on new Ordovician and Silurian fossils from the Northern Shan States. Palaeontologia Indica, New Series 6, 1 - 98.","Tripp, R. P., Zhou, Z. - Y. & Pan, Z. - Q. (1989) Trilobites from the Upper Ordovician Tangtou Formation, Jiangsu Province, China. Transactions of the Royal Society of Edinburgh, Earth Sciences, 80, 25 - 68. https: // doi. org / 10.1017 / S 0263593300012256"]}

Hadromeros ? submitis (Reed, 1915) Fig. 13.1 1915 Cheirurus submitis Reed, p. 49, pl. 8, figs 13,14. Material. Lectotype (selected herein): cranidium from Upper Naungkangyi Beds (Katian), Lilu, northern Shan State, Myanmar, Fig. 13.1 (Reed, 1915, pl. 8, figs 13,14), GSI 11560. Discussion. We illustrate here a cast taken from the lectotype, original of Reed (1915, pl 8. fig. 14). Only the cephalon is known of this species, which is only generally cheirurine, and invites comparison with those of many other species of similar age. It does, however, have very large, prominent but scattered tubercles on the cheeks and frontal lobe of the glabella. Many somewhat similar later Ordovician Chinese cheirurines have been assigned to the genus Parisoceraurus by Zhou & Zhen (2008) but these do not have such prominent tubercles. One species from the Pagoda Formation of Sichuan attributed (under open nomenclature) to Hadromeros by Zhou et al. (2016, pl. 14, fig. 14) does invite comparison with H.? submitis in showing very coarse, scattered tubercles over the fixed cheeks and forward part of the glabella, and may support a tentative assignment to Hadromeros. However, the Sichuan specimen and the type species of Hadromeros both show relatively long (tr.) glabellar furrows compared with H.? submitis, while the frontal glabellar lobe of the latter is relatively short (sag.) and wide. This structure seems to be unusual in cheirurids, and the distinctive glabellar lobation of the Myanmar species may indicate that it could belong to an undescribed genus, but without a pygidium this cannot be verified., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on pages 340-341, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Reed, F. R. C. (1915) Supplementary Memoir on new Ordovician and Silurian fossils from the Northern Shan States. Palaeontologia Indica, New Series 6, 1 - 98.","Zhou, Z. - Y. & Zhen, Y. - Y. (Eds.) (2008) Trilobite Record of China. Science Press, Beijing, 20 pp.","Zhou, Z. - G., Zhou, Z. - Y. & Xiang, L. - W. (2016) Trilobite fauna from the Ordovician Pagoda Limestone Formation of Central and Western Yangtze block, China. Geological Publishing House, Beijing, 422 pp. [in Chinese]"]}

Sphaerocoryphe Angelin 1854 Type species. Sphaerocoryphe dentata Angelin, 1854, Upper Ordovician, Sweden., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 341, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Angelin, N. P. (1854) s. n. In: Palaeontologia Scandinavica I. Crustacea Formationis Transitionis Fasc. 2. Academiae Regiae Scientarum Suecanae, Holmiae, pp. 21 - 92."]}

Ovalocephalus Koroleva, 1959 Type species. Ovalocephalus ovatus Koroleva 1959, original designation, Upper Ordovician, Kazakhstan., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 335, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Koroleva, M. N. (1959) New genera of trilobites from the Middle and Upper Ordovician or northern Kazakhstan. Doklady Akademia Nauk SSR, 124, 1313 - 1316. [in Russian]"]}

Encrinurella Reed, 1915 Type species. By monotypy, Pliomera insangensis Reed, 1906, Naungkangyi Beds, northern part of the Shan State., Published as part of Fortey, Richard A., Wernette, Shelly J. & Hughes, Nigel C., 2022, Revision of F. R. C. Reed's Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China, pp. 301-356 in Zootaxa 5162 (4) on page 333, DOI: 10.11646/zootaxa.5162.4.1, http://zenodo.org/record/6810290, {"references":["Reed, F. R. C. (1915) Supplementary Memoir on new Ordovician and Silurian fossils from the Northern Shan States. Palaeontologia Indica, New Series 6, 1 - 98.","Reed, F. R. C. (1906) The Lower Paleozoic fossils of the Northern Shan States, Upper Burma. Palaeontologia Indica, New Series 2, 1 - 154."]}

The field collections made from Burma (Myanmar) by the Geological Survey of India, and described by F.R.C. Reed more than a century ago, still provide the only ‘ground truthing’ for an important region of the Ordovician marginal terranes fringing Gondwana. A revision of these faunas is overdue, particularly as it is likely that further collections cannot be made in the northern Shan State in the near future. The specimens, stored in the Geological Survey of India collections in Kolkata, cannot be loaned. Sixteen species are fully revised herein; another twelve species are left under open nomenclature because of inadequacies in the material. Several of Reed’s species subsequently became type species of genera that have proved to be widespread: Birmanites Sheng, 1934, Encrinurella Reed, 1915, Neseuretinus Dean, 1967, and Pliomerina Chugaeva, 1956. Reed’s Ordovician trilobite collections came from two main areas: northern Shan State (Myanmar), and westernmost Yunnan (China). The Burmese (Myanmar) collections are from the Upper Ordovician (Katian) while Yunnan specimens are from the Middle Ordovician (Darriwilian), though Upper Ordovician trilobites also occur in the area. Both collections are predominantly from clastic strata. Based on a small new Katian collection from Pupiao, we report Neseuretinus birmanicus (Reed, 1906) in common between the northern part of the Shan State and western Yunnan. A few genera (Dionide Barrande, 1847, Phorocephala Lu, 1957, Lonchodomas Angelin, 1854, Nileus Dalman, 1827) are distributed worldwide, and include pelagic (Phorocephala) or deeper benthic (Dionide) taxa. The palaeogeographic comparisons offered by the other taxa are mostly peri-Gondwanan and extend from southwest China westwards (present geography) as far as the Iberian Pennsula. Birmanites is the type genus of a subfamily (Birmanitinae Kobayashi, 1960, revived herein) widely distributed over Ordovician Gondwana, and absent from Laurentia, Baltica and North China/Siberia. Mioptychopyge Zhou, Dean, Yuan & Zhou, 1998, probably belongs with the same group and is otherwise known from South China. Parillaenus Jaanusson, 1954, is also peripheral Gondwanan, as is Prionocheilus Rouault, 1847. The Reedocalymeninae Kobayashi, 1951 (Neseuretinus, Reedocalymene Kobayashi, 1951) are similarly diagnostic of peri–Gondwanan sites. However, some genera (Pliomerina, Encrinurella, Ovalocephalus Koroleva, 1959) have been associated with other oriental and Australian occurrences in particular, with ‘outliers’ in certain terranes in Kazakhstan, i.e. palaeotropical Gondwana.

Newfoundlandops karimae n. sp. Plates 11, 12 2019 Sphaerexochus n. sp.; Adrain and Karim, fig. 4.11. Material. Holotype, pygidium, GSC 135201 (Pl. 12, figs 8, 11, 12, 15, 18), and assigned specimens GSC 135190– 135199, 135202–135206, 135354, all from horizon TCM 18. Etymology. For Talia Karim. Diagnosis. As for genus. Description. Cranidial measurements were made on the specimens of Plate 11, figures 1, 4, 16. For the measurement of the cranidial width, in the specimens where the cranidium was preserved only on one side, the distance to the sagittal line from the side was doubled. Cranidium broadly semicircular in outline, wider than long, with sagittal length 64.3% (58.5–72.2%) maximum width, maximum width across the genal angles excluding the genal spines, vaulted dorsally in medial part; fixigenal field strongly downturned in anterior view, anterior part sloping downwards from the horizontal; anterior border short (sag., exsag.), describing a broad anteriorly directed arch, overhung by the anterior part of the glabella in dorsal view except for the lateral regions, medial region deflected dorsally in anterior view (e.g., Pl. 11, fig. 15), dense, equally distributed sculpture of tiny granules on entire surface; anterior border short (sag., exsag), deeply incised, shallower medially, describing an anteriorly directed arch; glabella subcircular in outline, maximum width across L2, sagittal length 66.6% (56.9–72.2%) maximum width (tr.); medial part, from L1 to the medial part of L2, slightly forwardly expanding; S3 tapering forward, posterolateral corners rounded, anterior margin describing a broad arch, posterior margin with central part transverse and abaxially behind L1 slightly bowed posteriorly; glabella strongly dorsally vaulted, anterior to S1 sloped downward from the horizontal (e.g., Pl. 11, fig. 18), surface densely covered by tiny granules equally distributed across the surface; S1–S3 well defined, deeply incised, relatively short (exsag.), extending about one quarter of the glabellar width; S1 longer (exsag.) and deeper than S2/S3, extending further adaxially than S2/S3, transversely directed with the proximal end turned posteriorly and followed by a shallow depression that connects with SO and isolates L1 from the median glabellar lobe (e.g., Pl. 11, figs 4, 16); S2/S3, shallower, shorter (exsag.) and narrower than S1, running subparallel to S1 but more transversely directed in proximal part; SO similar in length (sag., exsag.) and depth to S1, transverse in medial part, slightly bowed posteriorly laterally; LO subrectangular in outline, longer sagittally, shorter exsagittally, anterior margin transverse medially and posteriorly bowed laterally, posterior margin slightly arched posteriorly; L1 subquadrate in outline, slightly longer (exsag.) than L2, anterior margin transverse, posterior margin bowed posteriorly, slightly vaulted dorsally; L2 and L3 subrectangular in outline, similar in shape to L1; L2 slightly wider than L3, lateral margins slightly bowed laterally; frontal lobe semicircular in outline, slightly shorter (sag.) than the rest of glabellar lobes; axial furrow deeper and wider posteriorly, similar to S1, narrowing and shallowing anteriorly to S1 with similar depth to S2 and S3; fixigenal field triangular in outline, with dense sculpture of tiny granules along with a few larger tubercles (e.g., Pl. 11, fig. 12), interocular fixigena relatively long (exsag.), extremely narrow, posterior fixigena subquadrate, length similar to that of interocular fixigena, wider than interocular fixigena, strongly downturned (e.g., Pl. 11, fig. 15), anterior margin directed slightly posteriorly; posterior border furrow short (exsag.), deeply incised, longer and deeper proximally, shallower distally, transversely directed adaxial to genal angle, then smoothly anteriorly curved; lateral border furrow directed anterolaterally, relatively narrow; posterior border with proximal part near LO and below L1 wedge shaped, rapidly lengthening (exsag.) distally, with anterior margin directed forwards and outwards, until maximum near genal spine, anterior margin almost transverse and posterior margin slightly running posteriorly, distally beyond the genal angle with smooth anterior curvature; genal spines of moderate length, directed posteriorly and slightly laterally, widest at base, tapering to the tip, ending in a pointed tip; lateral border short (exsag.), directed anteriorly and slightly laterally, wider (tr.) near the genal angle; posterior border, genal spine and lateral border share sculpture similar to that of fixigenal field; palpebral lobe very narrow (tr.), elongate (exsag.), in lateral view describing an arch directed dorsally (e.g, Pl. 11, fig. 18), posterior end set slightly anteriorly to distal end of S1, anterior end set opposite S2, no eye ridge present; palpebral furrow narrow, deeply incised, running length of palpebral lobe; doublure beneath LO short (sag), approximately half of the sagittal length of LO, smooth; doublure in posterior border extremely short (sag.), distally beneath genal angle slightly expanded forming a triangular corner (e.g., Pl. 11, fig. 22). Librigena elongate and narrow; eye relatively large, set anteriorly, elevated dorsally, differentiated from the field by a narrow and extremely shallow furrow (e.g., Pl. 11, fig. 14); librigenal field subtrapezoidal in outline, margin across base of the eye slightly shorter than margin next to border furrow, sloping downwards from the eye to the border with respect to horizontal, with dense sculpture of small granules equally distributed across the surface; border furrow broad, very shallow, almost effaced, describing a laterally directed arch, sculpture similar to that of field; lateral border relatively wide, elongate, inflated, with sculpture similar to border furrow; anterior projection short, narrow, curved laterally; posterior facial suture long, broadly describing an outwardly convex arch, subtle change in slope opposite border furrow; anterior facial suture short, describing a curved outwardly arch; doublure expanded with similar width as the border (e.g., Pl. 11, fig. 23), describing an outwardly directed arch, smooth. Rostral plate unknown. Hypostomal measurements were made on the specimen of Plate 12, figure 3. Hypostome subquadrate in outline, slightly wider than long, with sagittal length 83.3% maximum width across lateral shoulders, moderately vaulted anteriorly in medial part; anterior border gently arched anteriorly, short (sag., exsag.), merging smoothly with anterior wings; anterior border furrow very short (sag.), gently bowed anteriorly similar to anterior border, very shallow; anterior wings small, triangular in shape, slightly pointed dorsally (e.g., Pl. 12, fig. 7); lateral notch well defined, gently concave dorsoventrally; posterior wings not prominent, deflected dorsally and inwards; middle body subtrapezoidal in outline, shorter (sag.) than wide (tr.) with sagittal length 63.2% middle body maximum width, moderately vaulted ventrally, especially anteriorly, anterior lobe larger than posterior lobe; anterior lobe ovoid in outline, wider than long, longer (sag.) medially, tapering laterally, maximum width across anterolateral corners, anterolateral corners pointed, anterior margin gently curved anteriorly, posterior margin gently curved posteriorly; posterior lobe slightly shorter (sag.) and narrower than anterior lobe, anterior margin slightly bowed posteriorly, posterior margin arched posteriorly with the median part almost transverse; middle furrow separates anterior and posterior lobes of the middle body, short (sag.), shallow, almost effaced medially, describing a slightly posteriorly curved arch; maculae ovate in outline; border furrow deeply incised anteriorly across the middle body, shallowed posteriorly, wide, narrower anteriorly and expanding slightly posteriorly; lateral border expanded, slightly wider across the lateral shoulder (e.g., Pl. 12, fig. 3), outer margin subtly arched outward at shoulders; posterior border long (exsag.), bilobate in outline (e.g., Pl. 12, figs 2, 3), medial part constricted, shorter (sag.), distally expanded with posterior margin describing a prominent posteriorly directed arch, slightly sloping ventrally from the horizontal; middle body and lateral border with sculpture of dense medium sized granules; beneath lateral and posterior borders doublure broad with similar width as lateral and posterior border (e.g., Pl. 12, fig. 2). Thorax unknown. Pygidial measurements are based on the specimens of Plate 12, figures 8, 10. Pygidium approximately semicircular in outline, broad (tr.), relatively short (sag.), with sagittal length (excluding articulating half-ring) 45.5% (44.1–46.8%) maximum width, slightly dorsally vaulted in anterior axial region, posteriorly sloping down from the horizontal (e.g., Pl. 12, figs 9, 12, 13); fulcrum set close to axis, with pleura slightly downturned beyond the fulcrum; articulating half-ring longer medially with sagittal length 10.9% (10.3–11.5%) maximum pygidial length, tapering abaxially, anterior margin slightly bowed anteriorly in medial part, posterior margin slightly bowed posteriorly in medial part, describing a dorsally directed arch in anterior view; articulating furrow short (sag., exsag.), slightly longer medially, deeply incised laterally, slightly shallowing medially, subtly bowed posteriorly, nearly transverse; axis subtriangular in outline, with sagittal length 41.9% (41.4–42.3%) pygidial sagittal length and width 32.3% (32.2–32.3%) pygidial width, composed of three axial rings (e.g., Pl. 12, figs 1, 8, 10), vaulted anteriorly, gradually decreasing inflation posteriorly with posterior part almost flat, with dense sculpture of evenly distributed tiny granules, row of larger tubercles present in the posterior part of axial rings; first and second axial rings similar in shape, subrectangular in outline; first axial ring longer and slightly wider than second axial ring, medially slightly shorter (sag.) and subtly expanding forward, anterior margin slightly bowed posteromedially, posterior margin slightly bowed anteromedially, corners squared off; third axial ring semicircular in outline, narrower (tr.) and slightly shorter (sag.) than second axial ring, anterior margin transverse, posterior margin posteriorly curved; terminal piece absent; first inter-ring furrow slightly narrower (tr.) and with same length as articulating furrow, slightly broader medially, deeply incised, becoming shallower in medial part, running transversely; second inter-ring furrow similar to the first inter-ring furrow, slightly narrower (tr.) and shorter (sag.); axial furrow narrow, wider in the intersection with the inter-ring furrows and interpleural furrows, more deeply incised anteriorly opposite the first axial ring and shallowing posteriorly; three interpleural furrows, similar in width and depth to inter-ring furrow, with first interpleural furrow longer (sag.) and deeper, running posterolaterally, second interpleural ring shorter strongly curved backwardly, third interpleural furrow directed posteriorly; three pleural segments extended by thick flattened pleural spine, distally sloping down with respect to the horizontal, proximal part divided in anterior and posterior pleural segment by a pleural furrow; pleural furrow narrow (tr.), running anteriorly in the pleura from the intersection with the axial furrow to the fulcrum describing a posteriorly directed arch (e.g., Pl. 12, figs 1, 8, 10), deeper proximally and shallow distally, deeply incised in the first pleural segment, shallower in the second and shallowest in the third pleural segment; first pleural segment proximally similar in length (sag.) to axial ring, lengthening gradually distally, anterior margin transverse adaxial to fulcrum, posterior margin slightly convex anteriorly, proximally divided into anterior and posterior bands by pleural furrow; anterior band highly vaulted dorsally, distally extended by a thick pleural spine, tapering distally, anterior margin bowed anterolaterally, posterior margin running posterolaterally, slightly vaulted dorsally (e.g., Pl. 12, fig. 15), ovoid in cross section, distal tip slightly rounded; second pleural segment similar in shape to first pleural segment, with pleural spine curved more strongly posteriorly, anterior band less vaulted dorsally; third pleural segment subrectangular in outline, directed posteriorly, distal tip more gently rounded than the others; pygidial border expressed ventrally as a narrow rim, describing a narrow (tr.) posteriorly directed arch in the medial part, distally beyond the medial arch running anterolaterally, not visible dorsally; pleural segments with dense sculpture of small tubercles equally distributed in all over the surface, with a few larger tubercles aligned in a row (e.g., Pl. 12, figs 15, 16, 20); doublure very short, smooth, with medial arch slightly longer and strongly directed upwards; distal part shorter and directed downwards. Discussion. See genus discussion., Published as part of Adrain, Jonathan M. & Pérez-Peris, Francesc, 2021, Middle Ordovician (Darriwilian) cheirurid trilobites from the Table Cove Formation, western Newfoundland, Canada, pp. 1-73 in Zootaxa 5041 (1) on pages 32-34, DOI: 10.11646/zootaxa.5041.1.1, http://zenodo.org/record/5531880

Harebayaspis plurima n. sp. Plates 13–16 Material. Holotype, pygidium, GSC 135277 (Pl. 16, figs 8, 9, 13, 17, 18), from horizon TCM 24, and assigned specimens GSC 135256, 135257, 135259, 135260, 135261, 135264–135268, 135274, 135275 from horizon TCM 24, GSC 135258, 135262, 135273, 135276, 135279 from horizon TCM 18, GSC 135255, 135263, 135269, 135271, 135272, 135278 from locality TCL 2, and GSC 135270 from locality TCL 6. Etymology. Latin plurimus: most, in reference to the high number of pygidial segments. Diagnosis. Eye set close to glabella, eye ridge short; fixigena abaxial to palpebral lobe narrow and turned posteriorly; librigenal field with large caecal pits and robustly inflated caecal trunks; pygidium with seven segments. Description. Cranidial measurements are based on the specimens of Plate 13, figures 2, 17. Cranidium subtrapezoidal in outline, broad (tr.) with maximum width across genal angles (excluding genal spines), tapering forward, slightly vaulted medially, in anterior view fixigenal field downturned abaxially, in lateral view subtly sloping downwards from the horizontal anteriorly; anterior border describing a broad arch directed forward with the medial portion opposite to the frontal lobe of the glabella almost transverse, medially and in most distal region shorter (sag., exsag.), maximum length (sag.) opposite intersection of S3 with axial furrow (e.g., Pl. 13, figs 2, 3), in anterior view medial part slightly vaulted dorsally (e.g., Pl. 13, fig. 5), gradually flattening distally, with sculpture of densely and evenly distributed tiny granules; anterior border furrow short (sag.), deeply incised, describing an anteriorly directed arch opposite glabella, with the median part almost transverse, distally beyond the glabella running slightly posteriorly, slightly anteriorly convex; glabella subrectangular in outline, with sagittal length 98.85% (96.2–101.5%) maximum glabellar width across L1, lateral margins subparallel, subtly tapering forward, anterolateral corners slightly rounded, posterolateral corners more squared off, anterior margin describing anterior arch with the medial part almost transverse, posterior margin with medial part transverse and distally slightly concave anteriorly across L1, anterior part slightly vaulted, posterior part flatter, sloped downward from the horizontal anterior to S1 (e.g., Pl. 13, fig. 5), with sculpture of dense medium-sized tubercles (larger than on the anterior border) arranged in arcs flanking the glabellar furrows (e.g., Pl. 13, figs 1, 2); S1–S3 well defined, deeply incised, relatively short (exsag.), extending about three quarters of the glabellar width; S1 slightly longer (sag.) than S2/S3, deeply incised distally and shallower proximally, directed posteromedially with the most proximal part curving more posteriorly, not connected with SO, proximal tip followed by a shallow dorsal depression that connects with SO and separates L1 from the median glabellar part; S2 parallel to S1, similar width and depth to S1; S3 shorter than S1/S2, strongly directed backwards; SO deeply incised, slightly shallower medially, long (sag.) behind median glabellar area, shorter abaxially; LO subrectangular in outline, relatively long in medial part behind median glabellar area, slightly shorter laterally, anterior margin transverse, slightly anteriorly concave medially, with distal part running slightly forward, posterior margin describing a broad posteriorly directed arch, corners squared off with the anterior corner slightly more extended outwardly than posterior corner, sculpture similar to that of the glabella; L1 wedge-shaped, slightly longer (exsag.) than L2, posterior margin subtly bowed posteriorly, dorsally inflated compared with the median area of the glabella (e.g., Pl. 13, fig. 11); L2 and L3 subrectangular in outline, similar in size, slightly shorter (exsag.) than L1; frontal lobe subtrapezoidal in outline, broader anteriorly, tapering posteriorly, slightly shorter than L1–L3; axial furrow deep and narrow, similar to the glabellar furrows; fixigenal field subtriangular in outline, with sculpture of dense irregular caecal pits of medium size and small tubercles distributed evenly across the surface; anterior fixigena shorter (exsag.) and narrower (tr.) than posterior part, in anterior view almost transverse to the horizontal, divided by eye ridge into anterior and posterior part (e.g., Pl. 13, figs 1, 2, 3, 10); anterior part very small with same width as the rest of anterior fixigena, very short (sag.), shorter laterally; posterior part of the anterior fixigena triangular in outline, anterior margin anterolaterally concave; posterior part of the fixigena subrectangular in outline, wider than long, anterior margin directed slightly posteriorly, in anterior view proximal part almost transverse to the horizontal and distal part downturned; posterior border furrow narrow deeply incised, short (sag., exsag.), transversely directed adaxial to genal angle, then abruptly curved anteriorly and slightly laterally; lateral border furrow with similar width and depth as the posterior border furrow, directed anterolaterally; posterior border shorter (exsag.) opposite L1, lengthening gradually abaxially until maximum length at genal angle, distally the genal angle is abruptly curved, anterior margin transverse, posterior margin slightly running posteriorly; genal spine conical in shape, directed posterolaterally, tapering distally, ending in a pointed tip (e.g., Pl. 15, figs 12, 13, 15, 16); lateral border short (exsag.) and narrow (tr.), directed anteriorly and slightly laterally, wider near the genal angle, narrowing forward; posterior border, genal spine and lateral border share a sculpture of densely distributed tiny tubercles; palpebral lobe small, posterior end set opposite L2, anterior end continuous with a well defined eye ridge (e.g., Pl. 13, figs 3, 6, 10), eye ridge running adaxially and anteriorly, connected proximally to axial furrow just posterior to the intersection of S3 with axial furrow; palpebral furrow running anteriorly from the posterior end of the palpebral lobe, merged anteriorly with a fine furrow running along the posterior side of the eye ridge; doublure beneath LO short (sag.). approximately half the sagittal length of LO; very short (exsag.), transverse doublure beneath the posterior border, slightly expanded under the genal angle. Librigenal measurements were made on the specimens of Plate 14, figures 18, 19, 20. Librigena narrow, elongate; eye small, set in the middle of the librigena, separated from field by smooth, weakly inflated socle lacking sculpture; librigenal field triangular in outline, elongate and narrow, width of field 36.4% (31.6–40.7%) length along lateral border furrow; in lateral view field slopes downward from the base of the eye to border furrow; field with sculpture of small to medium caecal pits and anastomosing caecal trunks, with tiny tubercles scattered irregularly over trunks; border furrow deep, narrow, slightly bowed laterally; border narrow, with width 57.1% (50.0–66.7%) width of field, outer margin gently curved laterally; posterior projection slightly longer than anterior projection, slightly curved medially in external view; anterior projection curved medially; posterior facial suture long curving convexly laterally, changing slope opposite border furrow from slightly curved laterally through the border to adaxially (e.g., Pl. 14, fig. 18); anterior facial suture short, curved laterally, with a gentle slope opposite border furrow; lateral border doublure very narrow beneath the entire border (e.g., Pl. 14, figs 21, 22), lacking sculpture. Rostral plate, hypostome, and thorax unknown. Pygidial measurements were made on the specimens of Plate 15, figure 1, and Plate 16 figure 9. Pygidium approximately semicircular in outline, broader anteriorly across the first pleural segment, narrowing posteriorly, sagittal length (excluding articulating half-ring and pleural spines) 45.5% (40.3–45.5%) maximum width (excluding pleural spines), anterior part slightly vaulted medially; fulcrum set far from the axis (e.g., Pl. 16, fig. 18), pleurae slightly downturned distal to the fulcrum, almost transverse; articulating half-ring short, longer sagittally with sagittal length 10.0% (8.9–11.1%) pygidial length, shorter exsagittally, anterior margin broadly bowed anteriorly, posterior almost transverse, vaulted dorsally, smooth; articulating furrow short (sag., exsag.), longer sagittally, slightly shorter exsagittally, shallow, deepening exsagittally; axis composed of seven axial rings, narrow and elongate, with sagittal length 147.6% (142.3–152.9%) maximum width across first axial ring, slightly tapering posteriorly, slightly vaulted anteriorly, gradually flattening posteriorly (e.g., Pl. 16, fig. 8); axial rings with sculpture of evenly distributed medium-sized tubercles; first six axial rings similar in shape, subrectangular in outline, gradually reducing in length (sag.) and width (tr.) from the first to the sixth segment; each of first six segments slightly shorter sagittally, longer exsagittally, anterior margin slightly bowed posteriorly, posterior margin slightly bowed anteriorly, corners squared off; seventh axial ring semicircular in outline, longer sagittally, much shorter exsagittally, anterior margin transverse, posterior posteriorly bowed; terminal piece absent; six inter-ring furrows, decreasing gradually in length (sag.) and width (tr.) from anterior to posterior, longer sagittally, shorter exsagittally, shallow sagittally, slightly deeper exsagittally; axial furrow with width similar to length of articulating furrow, forming wider areas in the intersections with inter-ring furrows, pleural furrows and interpleural furrows, deeply incised anteriorly, shallowing posteriorly; first pleural segment divided by a short (exsag.) and deep pleural furrow; pleural furrow with transverse course, distal part slightly curved posteriorly (e.g., Pl. 16, fig. 9), anterior pleural band shorter (exsag.) than posterior pleural band, transverse, distal tip slightly curved posteriorly, extended slightly beyond the pygidial margin; posterior pleural band long (sag.), running transversely, curving posteriorly before reaching pygidial margin, slightly longer (exsag.) across the pygidial margin, extended beyond pygidial margin by a pleural spine; pleural spine running posterolaterally, conical in outline, circular in cross-section (e.g., Pl. 16, fig. 17); second to fifth pleural segments with similar morphology, divided in anterior and posterior band by a pleural furrow as the first pleural segment, pleural spines more posteriorly directed in the more posterior segments; sixth and seventh pleural segments with pleural furrow and anterior pleural band obscure, segments strongly directed backwards; pleural segments separated by six interpleural furrows similar in lenght (sag.), width (tr.) and depth to pleural furrows, forming a wider area distally in the intersection with the pleural furrows (e.g., Pl. 16, figs 9, 14); posteriorly, interpleural furrows become gradually narrower (tr.), ending distally in the pygidial margin, first interpleural furrow running almost transversely, curving posteriorly slightly distally, posterior furrows directed more strongly posteriorly, shallowing distally across the pygidial margin; pleural segments with dense sculpture of medium-sized tubercles, similar to axis; pygidial margin forming continuous ventral rim (e.g., Pl. 15, fig. 2, Pl. 16, fig. 13); doublure very short, set vertically above margin (e.g., Pl. 15, fig. 4, pl. 16, fig. 18). Discussion. Harebayaspis plurima is most similar among known species to H. rafi, particularly in cephalic features. The eyes are similarly close to the glabella, with relatively short eye ridges. The portion of the fixigena abaxial to the palpebral lobe is quite narrow. In both H. jacquelinae and H. pengi the eye is set further abaxially, the eye ridge is longer, and the abaxial portion of the fixigena is much wider in dorsal view (in large part because it is directed more laterally instead of ventrally). Librigenae of H. plurima have almost the same dimensions as those of H. rafi, and both differ from the wider field seen in H. pengi. The librigenae differ in the larger caecal pits developed on the field in H. plurima. The species differ most obviously in the presence of seven pygidial segments in H. plurima versus four in H. rafi. Even here, though, comparison of just the rear four pygidial segments of H. plurima with the entire pygidium of H. rafi reveals substantial similarity, with faint paired axial tubercles and similar spine positions. Though they are broken in many specimens, the spines are apparently relatively longer in H. plurima., Published as part of Adrain, Jonathan M. & Pérez-Peris, Francesc, 2021, Middle Ordovician (Darriwilian) cheirurid trilobites from the Table Cove Formation, western Newfoundland, Canada, pp. 1-73 in Zootaxa 5041 (1) on pages 35-37, DOI: 10.11646/zootaxa.5041.1.1, http://zenodo.org/record/5531880

Mainbrookia n. gen. Type species. Mainbrookia becki n. sp., from the Table Cove Formation (Darriwilian), western Newfoundland, Canada (Laurentia). Other species. Sphaerocoryphe akimbo Tripp, 1967, Stinchar Limestone Formation (Darriwilian), South Ayrshire, Scotland (Laurentian-affinity Midland Valley Terrane); Sphaerocoryphe saba Tripp, 1962, Confinis Formation (Darriwilian), South Ayrshire, Scotland (Laurentian-affinity Midland Valley Terrane). In addition, provisionally assigned are remaining poorly known Laurentian-affinity forms from the Darriwilian. From the Confinis Formation (Darriwilian), South Ayrshire, Scotland (Laurentian-affinity Midland Valley Terrane): Sphaerocoryphe sp. A of Tripp (1962, p. 21), Sphaerocoryphe sp. B of Tripp (1962, p. 22), Sphaerocoryphe sp. C of Tripp (1962, p. 22). From the Stinchar Limestone Formation (Darriwilian), South Ayrshire, Scotland (Laurentian-affinity Midland Valley Terrane): Sphaerocoryphe sp. A of Tripp (1967, p. 66), Sphaerocoryphe sp. B of Tripp (1967, p. 66), Sphaerocoryphe sp. of Tripp (1979, p. 350). Etymology. After the town of Main Brook, which is near to the locality from which the type species was collected. Gender is feminine. Diagnosis. Cranidial fixigenal lateral border spine present; pygidium with three axial rings and three pairs of spines, first pair large, elongate, and dorsally produced. Discussion. The assigned Scottish species are somewhat difficult to fully interpret, as they are all based on coarsely preserved internal mold material illustrated with very small photographs. Nevertheless, M. akimbo has a pygidium with essentially the same morphology as that of M. becki (Tripp, 1967, pl. 4, figs 8, 9) and it definitely has a fixigenal lateral border spine (Tripp, 1967, pl. 4, fig. 4). Mainbrookia saba is not known from the pygidium, but definitely has a fixigenal lateral border spine (Tripp, 1962, pl. 3, fig. 11). The remaining open nomenclature Darriwilian Scottish species are largely scraps that lack evidence of diagnostic features. We assign them provisionally to Mainbrookia, but obviously this should be revisited if more information becomes available., Published as part of Adrain, Jonathan M. & Pérez-Peris, Francesc, 2021, Middle Ordovician (Darriwilian) cheirurid trilobites from the Table Cove Formation, western Newfoundland, Canada, pp. 1-73 in Zootaxa 5041 (1) on page 14, DOI: 10.11646/zootaxa.5041.1.1, http://zenodo.org/record/5531880, {"references":["Tripp, R. P. (1967) Trilobites from the upper Stinchar Limestone (Ordovician) of the Girvan District, Ayrshire. Transactions of the Royal Society of Edinburgh, 67, 43 - 94. https: // doi. org / 10.1017 / S 0080456800023899","Tripp, R. P. (1962) Trilobites from the \" confinis \" Flags (Ordovician) of the Girvan district, Ayrshire. Transactions of the Royal Society of Edinburgh, 65, 1 - 40. https: // doi. org / 10.1017 / S 0080456800012291","Tripp, R. P. (1979) Trilobites from the Ordovician Auchensoul and Stinchar Limestones of the Girvan District, Strathclyde. Palaeontology, 22, 339 - 361."]}

Harebayaspis n. gen. Type species. H. plurima n. sp., from the Table Cove Formation (Darriwilian), western Newfoundland, Canada (Laurentia). Other species. Parapilekia jacquelinae Fortey, 1980, Valhallfonna Formation (Dapingian), Ny Friesland, Svalbard, arctic Norway (Laurentian-affinity East Svalbard Terrane); Macrogrammus pengi Edgecombe, Chatterton, Vaccari, and Waisfeld, 1999, Gualcamayo Formation (Darriwilian), San Juan Province, Argentina (Cuyunia Terrane); Macrogrammus rafi Edgecombe, Chatterton, Vaccari, and Waisfeld, 1999, Las Aguaditas Formation (Darriwilian), San Juan Province, Argentina (Cuyunia Terrane); Macrogrammus sp. of Waisfeld and Vaccari (2003, p. 303), Gualcamayo Formation (Dapingian), San Juan Province, Argentina (Cuyunia Terrane); Harebayaspis sp. (“Undetermined proparian species” and “Undetermined genus and species” of Ross [1958, p. 569, pl. 84, figs 9–11]), limestone clast in volcaniclastic breccia of the Valmy Formation (Floian), Lander County, Nevada, USA. Etymology. From Hare Bay, in which the type locality of the type species is located, and the Greek noun aspis, shield. Gender is feminine. Diagnosis. Eyes relatively anteriorly placed, rear of palpebral lobe just behind lateral termination of S2; area of fixigenal field present anterior to eye ridge but of restricted extent; L1 with subquadrate outline, S1 abaxially transverse, with adaxial posterior bend; librigenal field long (exsag.) and narrow (tr.); pygidium with 4–7 segments. Discussion. A new genus is proposed for a group of Laurentian or Laurentian-affinity species known from the Floian to Darriwilian. Peng (1990) recognized that the only species of this group then known, Parapilekia jacquelinae Fortey, 1980, from the Dapingian of the East Svalbard Terrane, had cranidial similarities to the poorly known Macrogrammus scylfense Whittard, 1966, from the Floian of the Shelve Formation of Shropshire, England (Avalonia), and suggested that Fortey’s species should probably be assigned to Macrogrammus. Edgecombe et al. (1999) described two new species from the Darriwilian of Argentina (Cuyunia). They remarked on the unsatisfactory state of knowledge of M. scylfense, and also upon the obvious morphological differences between it and the better known Laurentian-affinity species. Nevertheless, they considered that two features - a large area of fixigena anterior to the eye ridge with the anterior section of the facial suture running straight forward rather than anteromedially - suggested relationship with the Avalonian species. We would argue that the large size of the anterior fixigenae is shared between M. scylfense and the Avalonian Darriwilian Macrogrammus sp. of Lane (1971, p. 37, pl. 7, figs 21a, b), but that this region is considerably smaller in all of the Laurentian species. Both Macrogrammus scylfense and Macrogrammus sp. of Lane (1971) differ from any of the Laurentian-affinity species in their extreme posterior eye position, with the palpebral lobe set opposite L1, and an obliquely set but nearly straight S1 which cuts directly posteromedially, versus an abaxially transverse furrow that is deflected posteriorly adaxially in the Laurentian-affinity group. For these reasons, we restrict Macrogrammus to the two Avalonian species that share these features, and propose Harebayaspis for the Laurentian-affinity group. Further evaluation of relationship would require much more knowledge of the Avalonian species., Published as part of Adrain, Jonathan M. & Pérez-Peris, Francesc, 2021, Middle Ordovician (Darriwilian) cheirurid trilobites from the Table Cove Formation, western Newfoundland, Canada, pp. 1-73 in Zootaxa 5041 (1) on pages 34-35, DOI: 10.11646/zootaxa.5041.1.1, http://zenodo.org/record/5531880, {"references":["Fortey, R. A. (1980) The Ordovician trilobites of Spitsbergen. III. Remaining trilobites of the Valhallfonna Formation. Norsk Polarinstitutt Skrifter, 171, 1 - 163.","Edgecombe, G. D., Chatterton, B. D. E., Vaccari, N. E. & Waisfeld, B. G. (1999) Ordovician cheirurid trilobites from the Argentine Precordillera. Journal of Paleontology, 73, 1155 - 1175. https: // doi. org / 10.1017 / S 0022336000031048","Waisfeld, B. G. & Vaccari, N. E. (2003) Trilobites. In: Benedetto, J. L. (Ed.), Ordovician Fossils from Argentina. Secretaria de Ciencia y Tecnologia, Universidad Nacional de Cordoba, Cordoba, pp. 295 - 409.","Ross, R. J. Jr. (1958) Trilobites in a pillow-lava of the Ordovician Valmy Formation, Nevada. Journal of Paleontology, 32, 559 - 570.","Peng, S. - C. (1990) Tremadoc stratigraphy and trilobite faunas of northwestern Hunan. 2. Trilobites from the Panjiazui Formation and the Madaoyu Formation in Jiangnan Slope Belt. Beringeria, 2, 55 - 171.","Whittard, W. F. (1966) The Ordovician trilobites of the Shelve Inlier, west Shropshire. Part 8. Monographs of the Palaeontographical Society, 508, 265 - 306.","Lane, P. D. (1971) British Cheiruridae (Trilobita). Monographs of the Palaeontographical Society, 530, 1 - 95."]}

Laneites polydorus (Billings, 1865a) Plates 1–4 1865a Cheirurus polydorus Billings, p. 286, fig. 274. 1865b Cheirurus polydorus Billings; Billings, p. 374. 1890 Ceraurus polydorus Billings; Vogdes, p. 103. 1893 Ceraurus polydorus Billings; Vogdes, p. 290. 1910 Ceraurus polydorus Billings; Raymond, 1910, p. 240. 1915 Cheirurus polydorus Billings; Barton, p. 134. 1930 Ceraurinus polydorus Billings; Bradley, p. 178. 1963 “ Cheirurus ” polydorus Billings; Whittington, p. 85, pl. 25, fig. 10. 1963 “ Cheirurus ” polydorus Billings; Whittington and Kindle, fig. 3. 1965 Ceraurinella polydorus (Billings); Whittington, p. 408, pl. 60, figs. 1-11. 1967 Ceraurus polydorus (Billings); Ross, p. D23. 1971 Ceraurinella polydorus (Billings); Lane, p. 18, text-fig. 10. 1973 Ceraurinella polydorus (Billings); Čugaeva, p. 76. 1977 Ceraurinella polydorus (Billings); Ludvigsen, p. 960. 1980 Ceraurinella polydorus (Billings); Fortey, p. 78. 1981 Ceraurinella polydorus (Billings); Bruton and Harper, p. 171. 1985 Laneites polydorus (Billings); Přibyl and Vaněk in Přibyl et al., p. 161, pl. 5, figs 1, 2, text-figs. 8, 9. 1997 Ceraurinella polydorus (Billings); Adrain and Fortey, p. 99. 2003 Laneites polydorus (Billings); Jell and Adrain, p. 395. 2019 Sycophantia polydora (Billings); Adrain and Karim, fig. 4.10. Material. The lectotype, selected by Whittington (1965, p. 408), is an incomplete cranidium, GSC 685 (Whittington, 1963, pl. 25, fig. 10). Whittington (1965, pl. 60, figs. 1–11) illustrated three more cranidia and a pygidium. Silicified material illustrated herein, GSC 135161–135169, 135171–135189, 135353 is all from horizon TCM 18. Diagnosis. As the genus is monotypic, see genus diagnosis. Description. Cranidial measurements are based on the specimens of Plate 1, figures 1, 2, 15, 21. Cranidium subtrapezoidal in outline, broad (tr.) posteriorly with maximum width across genal angles (excluding genal spines), narrowing forward, slightly vaulted dorsally in medial part, fixigenal field flat in anterior view; anterior border short (sag.), shorter medially, subtly lengthened laterally, describing broad anteriorly directed arch with the medial part completely transverse and lateral part curving strongly posteriorly, forming rounded anterolateral corners (e.g., Pl. 1, figs 2, 3), distal tip set slightly anteriorly to the intersection of S3 and the axial furrow, sculpture of dense, tiny granules equally distributed over all the surface; anterior border furrow deeply incised, short (sag.), describing an anteriorly directed arch similar to the anterior border; glabella with length (sag.) 116% (97.2–135.8%) maximum width (tr.), sub-rectangular in outline, sub-parallel lateral margins, maximum width across L3, narrower at the base of L1, subtly expanded forward, anterolateral corners gently rounded, posterolateral corners rounded but more pointed than the anterolateral corners, anterior margin transverse with distal part slightly bowed posteriorly, posterior border transverse in the median portion with distal part across L1 slightly bowed posteriorly, weakly dorsally inflated, in lateral view anteriorly to S2 slightly sloped downward from the horizontal (e.g., Pl. 1, fig. 9); glabella with densely distributed tiny tubercles on entire surface; S1–S3 well defined, narrow (tr.), extending about one quarter of the glabellar width; S1 longest, extending slightly further adaxially than S2/S3, running adaxially and curving posteriorly, deeply incised distally, continued posteriorly as a faint depression that connects with SO and separates L1 from the median glabellar lobe (e.g., Pl. 1, figs 1, 16); S2 and S3 parallel, narrower (tr.) than S1, with marked posterior deflection medially, less posteriorly directed than S1; SO similar in depth and length (sag., exsag.) to S1–S3, shallowing medially; LO subrectangular in outline, long sagittally, shorter exsagittally with anterolateral and posterolateral corners angular, anterior margin transverse medially, posterior margin gently bowed posteriorly with the medial part almost transverse; L1 subquadrate, similar in size to L2 and L3, posterior margin subtly bowed posteriorly; L2 and L3 equal sized, quadrate in outline, L3 with lateral margin with light lateral bow; frontal lobe semicircular in outline, longer (sag.) than the rest of glabellar lobes; axial furrow similar in depth and width to glabellar furrows; fixigenal field sub-triangular in outline, narrow (tr.) anteriorly, wider posteriorly, with dense sculpture of tiny pits and small granules; anterior fixigenal field triangular in outline, short (exsag.), narrow (tr.), broader posteriorly, tapering forward, with small area in front of the eye ridge (e.g., Pl. 1, fig. 2); posterior fixigena subrectangular in outline, with similar length (exsag.) but wider (tr.) than anterior fixigenal field; posterior border furrow short (exsag.), deeply incised, distally slightly curving anteriorly, at the genal angle strongly curved anteriorly; lateral border furrow deep, directed anteriorly and adaxially; posterior border short (exsag.) with posterior margin transverse and anterior margin slightly curved anteriorly, expanding distally with maximum length (exsag.) at the genal angle, extended at genal angle by a broad-based genal spine (see Whittington, 1965, pl. 60, fig. 4), directed posterolaterally; lateral border wider (tr.) next to genal angle, narrowing forward, directed anteriorly and adaxially; palpebral lobe relatively large, margin gently arched laterally (e.g., Pl. 1, fig. 1), posterior end set opposite to the posterior part of L2, anterior part is continuous with a broad eye ridge; eye ridge tapering forwards, running inward and forward from the palpebral lobe to the intersection with axial furrow slightly posterior to S3 (e.g., Pl. 1, fig. 2); palpebral furrow narrow, deeply incised, running from the posterior tip of the palpebral lobe forward along the eye ridge finishing in the intersection with the axial furrow. Librigenal measurements were made on specimens of Plate 2, figures 17, 19, 21, Plate 4, figure 14. Librigena subtrapezoidal in outline; eye relatively large, bulbous, elongate, differentiated from the field by a narrow and shallow furrow (e.g., Pl. 3, fig. 31), elevated from the field; eye tilted forward, with the anterior end of the furrow set more abaxially than the posterior end; field subquadrate in outline, width 69.6% (65–72.7%) of exsagittal length along lateral border furrow, slightly expanding from the inner margin to the outer margin next to the border furrow, in lateral view laterally convex, dense sculpture of tiny granules and less densely arranged small pits equally distributed across the surface of the field, more scarce in the area close to the border furrow; small slightly inflated area sub-triangular in shape anterior to the eye (e.g., Pl. 2, figs 19, 21, Pl. 3, fig. 31, Pl. 4, fig. 14), with smoother sculpture differentiated from the rest of the field; border furrow deep, narrow; border elongated, exsagittal length of the librigenal field along the lateral border furrow 37.1 % (35.8–38.1%) length of the border, slightly bowed outwards; border elongate, broad (similar in width to the field), broader in medial portion, tapering anteriorly and posteriorly, slightly vaulted dorsally, internal and external margin arched outwards, dense sculpture of tiny granules equally distributed across entire external surface; posterior projection of the border elongate, triangular in outline, narrowing posteriorly, longer than anterior projection; anterior projection short, triangular in outline, narrowing anteriorly; anterior facial suture short, concave, describing a slightly curved outward arch, subtle change in slope opposite to border furrow with the suture across the field slightly steeper than across the border (e.g., Pl. 2, fig. 17); posterior facial suture long, posteriorly convex through the border, changing in slope opposite to border furrow to almost transverse inwards; doublure smooth, beneath the border half the width of border, beneath anterior projection triangular in outline tapering anteriorly, beneath posterior projection prominent, visible in dorsal view (e.g., Pl. 2, fig. 17). Rostral plate unknown. Hypostomal measurements were made on specimens of Plate 2, figures 1 and 12. Hypostome subcircular in outline, with sagittal length 88.7% (87.6-88.7%) maximum width (tr.), maximum width across anterior wings, slightly vaulted medially; anterior border gently arched anteriorly, very short (sag.) in medial area, expanding slightly laterally, merging smoothly with anterior wings; anterior border furrow shallow, short (sag.), slightly lengthened (exsag.) distally, anteriorly bowed; anterior wings prominent, subtriangular in outline, slightly extended beyond lateral shoulder, ventral pits expressed dorsally as large strongly dorsally deflected wing process (e.g., Pl. 2, fig. 10); lateral notch well defined, prominent, broadly concave dorsoventrally (e.g., Pl. 2, figs 4, 7, 9, 10); posterior wings smaller than anterior wings, deflected dorsally and inwards; middle body long (sag.), ovoid in outline, with sagittal length 133.6% (131.8–135.3%) width, anterior lobe much larger than posterior lobe, slightly vaulted medially and anteriorly (e.g., Pl. 2, fig. 9); anterior lobe ovoid in outline, anterior margin highly arched anteriorly, posterior margin arched posteriorly, maximum width anteriorly, slightly tapering posteriorly; posterior lobe of middle body U-shaped, short (sag.) with maximum length medially, tapering laterally, less inflated than anterior lobe and almost flat; middle furrow separating anterior and posterior lobes of the middle body, very shallow, especially medially where it is almost effaced, arched posteriorly; maculae reduced, elongate, ovoid in shape; border furrow deeply incised, deeper anteriorly and slightly shallower posteriorly, narrow, slightly wider across the anterior part of the posterior lobe; lateral border highly expanded anteriorly across the shoulder, narrower posteriorly, arched outwards at shoulders (e.g., Pl. 2, fig. 1); posterior border short (sag.), gently arched posteriorly, smooth margin; small pair of spines at the posterolateral corner of the border (e.g., Pl. 2, figs 12, 14); densely sculptured with tiny granules equally distributed around entire ventral surface; doublure slightly directed inwards dorsally, smooth, expanded beneath lateral border, slightly tapering backwards, shorter beneath posterior border. Total number of thoracic segments unknown; articulating half-ring broad (tr.), slightly shorter (sag) than the axial ring, vaulted dorsally as the axis, semicircular in outline, anterior and posterior border anteriorly arched; articulating furrow shallow across most of its course, slightly shorter (sag.) than the articulating half-ring and arched anteriorly but with distal apodemal pits deeply incised, narrow (tr.), running forward; axial ring subrectangular in outline, dorsally vaulted, long (sag.), lengthened laterally, slightly widerthan articulating half-ring (tr.), anterior margin almost transverse, turning forward in distal position, posterior margin almost transverse, slightly bowed posteriorly, distal tips pointed; axial furrow short, deep; articulating flange present along anterior and posterior margin of the pleurae, running transversely from the intersection with the axial furrow to the fulcrum, short (exsag.), slightly expanding distally and longest next to the fulcrum, flange curving dorsoventrally in the distal tip forming anteriorly the fulcral process and posteriorly the fulcral socket (e.g., Pl. 3, figs 13, 24, 26); flange separated from pleural ridge by a short (exsag.), relatively shallow articulating furrow; furrow visible in dorsal view laterally; pleurae constricted across the fulcrum dividing the pleura into a proximal part (adaxial to the fulcrum) and a distal part (abaxial to the fulcrum); proximal part rectangular in outline, flat in anterior view, same length proximally as the distal part of the axial ring, anterior and posterior margin almost transverse along proximal three quarters, running slightly posteriorly and anteriorly respectively, in the most distal quarter; both margins curve posteriorly and anteriorly forming a sagittal constriction in the pleura; in anterior view the constricted area of the pleura forms a small dorsally concave depression (e.g., Pl. 3, figs 3, 19); distal part extending in a pleural spine, running ventrolaterally, curved posteriorly, proximal part long (exsag.), narrowing distally, ending in a pointed tip, flat in cross section; proximal part of the pleura bears a pleural furrow (e.g., Pl. 3, figs 1, 8, 21), narrow, deeply incised, proximally connected with the axial furrow, running straight from the anterior part of the pleura posteriorly obliquely, shallowing at the pleural constriction (almost effaced), change direction running anteriorly, slightly directed outwards connecting with the anterior articulating furrow; raised rim visible ventrally marking the termination of segment with the pleural spine extended beyond; densely sculpted by tiny granules more densely arranged distally and in the anterior and posterior margin of the pleural spine (e.g., Pl. 3, figs, 17, 24, 25). Pygidial measurements were made on the best preserved specimens of Plate 4, figures 1, 3, 8, 16. Pygidium broad (tr.) with sagittal length (excluding articulating half-ring and pygidial spines) 38.5% (36–40.5%) maximum width; fulcrum set close to the axis, with pleura directed posteriorly; articulating flange straight along the anterior margin of the first pleural segment (e.g., Pl. 4, fig. 3), anterolaterally ending at fulcrum with a fulcral process visible in dorsal view; articulating half-ring long (sag.) with sagittal length 33.3% total sagittal length of the pygidium, tapering distally, highly vaulted dorsally, anterior margin anteriorly bowed, posterior margin transverse, sculpted with tiny granules; articulating furrow deeply incised, short (sag.), slightly broader medially; axis triangular in outline (e.g., Pl. 4, figs 1, 3, 8), vaulted anteriorly and less vaulted, almost flat, posteriorly, narrow with maximum width (across the first segment) 37.9% (36–39.1%) maximum width of the pygidium; axis consists of three axial rings and a terminal piece; first axial ring trapezoidal in shape, slightly longer (sag.) and broader (tr.) than the second axial ring, with anterior margin slightly broader than posterior margin, anterior margin straight, posterior margin slightly bowed anteriorly, almost transverse, posterolateral corner slightly rounded; second axial ring trapezoidal in shape, with anterior margin broader (tr.) than posterior margin, both margins slightly bowed anteriorly, posterolateral corner merged with second pygidial pleural band; third axial ring slightly shorter (sag.) and narrower (tr.) than second axial ring, anterior margin slightly bowed anteriorly, posterior margin curved anteriorly, abaxial extent not defined by axial furrow, smoothly merged with pleural field; terminal piece small, anterior margin anteriorly bowed, posteriorly almost effaced, not distinguishable from the pygidial pleural field; first inter-ring furrow as long (sag.) as articular furrow and slightly narrower (tr.), slightly longer in medial part, deeply incised becoming shallower in medial part, almost running transverse subtly bowed anteriorly; second inter-ring furrow similar to the first interring furrow, slightly narrower; third inter-ring furrow narrower than the rest, equal length (sag.), shallower in medial part, arched anteriorly; axial furrows only present anteriorly (e.g., Pl. 4, fig. 8), running from the intersection with the articulating furrow to the intersection with the first interpleural furrow, slightly narrower and shallower than articulating furrow, curved laterally; two interpleural furrows, both similar in width to inter-ring furrows, running in posterolateral direction, deeply incised proximally, shallowing distally, almost effaced next to the pleural margin; first pleural segment longer (sag.) than the rest, extended by a long, thick, conical, pleural spine, spine directed dorsally, laterally and posteriorly (e.g., Pl. 4, fig. 1, 6, 10), slightly curving abaxially, circular in cross section, thick proximally, tapering distally; pleural furrow in the first pleural segment located in the adaxial part (e.g., Pl. 4, fig. 8), running laterally and posteriorly from the axial furrow ending slightly beyond the pygidial margin; second and third pleural segments smaller than first, without pleural furrow, extended in short pleural spines, triangular in outline, second pleural spine slightly longer than third; pygidial border expressed ventrally as a narrow rim (e.g., Pl. 4, fig. 4, 5, 19), describing a posteriorly directed arch, only the anterolateral tips visible dorsally where the rim merges with the anterior flange; dense sculpture of small tubercles equally distributed across entire surface; doublure short, slightly longer sagittally, smooth, dorsally directed (e.g., Pl. 4, fig. 7, 12). Discussion. Whittington (1965) revised the species and provided excellent photographs of some incomplete crackout specimens from Table Cove. Our silicified material is important in that it provides the first information on the morphology of the librigena, hypostome, and thoracic segments, additional cranidia and pygidia, as well as ventral/internal morphology. The species was compared with relevant taxa in the genus discussion above., Published as part of Adrain, Jonathan M. & Pérez-Peris, Francesc, 2021, Middle Ordovician (Darriwilian) cheirurid trilobites from the Table Cove Formation, western Newfoundland, Canada, pp. 1-73 in Zootaxa 5041 (1) on pages 8-11, DOI: 10.11646/zootaxa.5041.1.1, http://zenodo.org/record/5531880, {"references":["Billings, E. (1865 a) s. n. In: Palaeozoic fossils. Vol. I (4). Geological Survey of Canada, Montreal, pp. 168 - 345.","Raymond, P. E. (1910) Trilobites of the Chazy formation in Vermont. Report of the Vermont State Geologist, 7, 213 - 248.","Whittington, H. B. (1965) Trilobites of the Ordovician Table Head Formation, western Newfoundland. Bulletin of the Museum of Comparative Zoology, Harvard, 132, 275 - 442."]}

Youngia hangii T.Deng, D.G.Zhang, Qun Liu & Z.M.Li, sp. nov., a new species of Asteraceae, is described and illustrated. It was collected in Wufeng County, Hubei Province, Eastern Central China. Youngia hangii is morphologically most similar to Y. rubida, but can be easily distinguished from the latter by capitula with 8–10 florets and the hairy leaf surface. Phylogenetic analyses, based on the internal transcribed spacers (ITS) and one chloroplast marker (rps16), showed that Y. hangii and Y. rubida were sister species with good support. The results of both phylogenetic analysis and the morphological data support the specific rank of Y. hangii.

Middle Ordovician (Darriwilian) species representing early Laurentian occurrences of the Subfamily Calymeninae Milne Edwards, 1840 (=Flexicalymeninae Siveter, 1977) are assigned to Atlanticalymene n. gen. (type species: A. bardensis n. sp. from the Table Cove Formation, western Newfoundland, Canada). They have routinely been confused with the older (Dapingian) calymenoidean taxon Protocalymene Ross, 1967. Revision of the type species of Protocalymene, P. mcallisteri Ross, 1967, from the Antelope Valley Formation, Funeral Mountains, California, indicates that it is not a calymenine, and that while it is clearly a calymenoidean its close affinity is otherwise difficult to determine. A single genuine calymenine species is known from the Laurentian Dapingian, and revised here as “Calymeninae n. gen.? n. sp. A” from the Antelope Valley Formation, Nevada, USA. A species from the Dapingian of Tarim, known from a single partial cranidium, appears to represent an older, extra-Laurentian species of Atlanticalymene.

Calymeninae n. gen. n. sp. Fig. 4 1999 Protocalymene new species A; Fortey and Droser, p. 197, fig. 8.11–8.14. 2013 “unnamed species described as ‘ Protocalymene n. sp. A’ by Fortey & Droser (1999) ”; Adrain, p. 310. Material. Figured specimens USNM 495698, 495699, and 511808 from the Antelope Valley Formation (Dapingian), “olenid bed” at Little Rawhide Mountain, Nye County, central Nevada, USA. Note that USNM 511808 was listed by Fortey and Droser (1999, p. 197) as “ USNM 495700”. However they had earlier in their paper assigned the latter number to a librigena of a species of Dimeropygiella (Fortey and Droser, 1999, p. 192, explanation of fig. 5.5); the calymenid specimen reillustrated herein has subsequently been assigned the number USNM 511808. Discussion. Fortey and Droser (1999) illustrated specimens from a deep water olenid-dominated assemblage in the Dapingian part of the Antelope Valley Formation. They assigned the material to Protocalymene. In its cranidial dimensions the species appears to be a calymenine. Its most unusual feature is the presence of a very long preglabellar field (e.g., Fig. 4.4) with fine tuberculate sculpture similar to that on the rest of the cranidium. Some younger calymenines have a long area between the glabella and anterior border, but it is typically a deep well that resembles an expanded anterior border furrow (e.g., Calymene (s.l.) frontosa Lindström, 1885 —see Clarkson and Howells [1981, pl. 79, figs 6, 7, 11]; species of Arcticalymene Adrain and Edgecombe, 1997). None show what appears to be a standard, sculptured preglabellar field as most have the front of the glabella separated from the anterior border only by a relatively deep and short anterior border furrow. The morphology in Fortey and Droser’s species could represent a transitional form. The anterior parts of the fixigenae are inflated and typically calymenine. They are separated from the sculptured preglabellar area by abrupt changes in slope running forward from the axial furrows. The anterior border appears to be calymenine in aspect, though it is not well known. Alternatively, the inferred environment of deposition is deep water and dysaerobic. The cranidia are very broad and have much more prominent caecal sculpture (including, especially, the bicomposite eye ridge) underlying the fine tubercles than is typical for a calymenine. It is conceivable that the unusual preglabellar morphology is part of a suite of adaptations to an oxygenstressed environment. While this Dapingian species broadly resembles A. bardensis in cranidial dimensions, especially the wide interocular fixigenae, it lacks the glabellar morphology considered apomorphic for Atlanticalymene. It has well de- veloped L2 and L3 and a deep S2. The glabella is relatively short compared to that of A. bardensis, but it is nearly parallel-sided versus the bell shape typical of calymenines. We agree with Fortey and Droser (1999) that the species, while very distinctive, is not well enough known to formally name. It is important as the oldest known Laurentian calymenine and the only known Dapingian species. It appears to represent a genus distinct from Atlanticalymene, formal naming of which must await the recovery of more material or related species from elsewhere., Published as part of Adrain, Jonathan M., Karim, Talia S. & McAdams, Neo E. B., 2020, Atlanticalymene, a new genus of Middle Ordovician (Darriwilian) calymenine trilobites, and revision of the calymenoidean genus Protocalymene Ross, pp. 1-55 in Zootaxa 4859 (1) on pages 13-14, DOI: 10.11646/zootaxa.4859.1.1, http://zenodo.org/record/4537316, {"references":["Fortey, R. A. & Droser, M. L. (1999) Trilobites from the base of the type Whiterockian (Middle Ordovician) in Nevada. Journal of Paleontology, 73, 182 - 201. https: // doi. org / 10.1017 / S 0022336000027712","Lindstrom, G. (1885) Forteckning pa Gotlands Siluriska Crustaceer. Ofversigt af Kongl. Vetenskaps-Akademiens Forhandlingar. Stockholm, 6, 37 - 100.","Clarkson, E. N. K. & Howells, Y. (1981) Upper Llandovery trilobites from the Pentland Hills, Scotland. Palaeontology, 24, 507 - 536.","Adrain, J. M. & Edgecombe, G. D. (1997) Silurian (Wenlock) calymenid trilobites from the Cape Phillips Formation, central Canadian Arctic. Journal of Paleontology, 71, 657 - 682. https: // doi. org / 10.1017 / S 0022336000040130"]}

Protocalymene mcallisteri Ross, 1967 Plates 8–15 1967 Protocalymene mcallisteri Ross, p. D27, pl. 9, figs 1–28. 1970 Protocalymene mcallisteri Ross; Ross, p. 92. 1977 Protocalymene macallisteri [sic] Ross; Kobayashi and Hamada, p. 125. non 1983 Protocalymene mcallisteri Ross; Andrawis et al. p. 66, fig. 1. 1990 Protocalymene mcallisteri Ross; Geyer, p. 111. 1999 Protocalymene mcallisteri Ross; Fortey and Droser, p. 197. 2002 Protocalymene mcallisteri Ross; Turvey, p. 56. 2003 Protocalymene mcallisteri Ross; Jell and Adrain, p. 431. 2005 Protocalymene mcallisteri Ross; Turvey, text-fig. 1. non 2012 Protocalymene mcallisteri Ross; Basse, p. 35. Material. Holotype, cranidium, USNM 145848 (Ross, 1967, pl. 9, figs 5–7), and assigned specimens SUI 137444–137520, Antelope Valley Formation (Dapingian), north of Pyramid Peak, west flank of Funeral Mountains, Death Valley National Park, California, USA. Diagnosis. See genus diagnosis. Description. Cranidial measurements were made on specimens from Pl. 8, figs 1–3, 10, 15, 21, Pl. 9, figs 1- 3, 11, 13, 19, 21, Pl. 10, figs 1–3, 10–12, 19, 20. Cranidium with strong dorsoventral relief, anterior and posterior fixigena strongly flexed downward from occipital lobe in lateral view, and anterior fixigena flexed upward toward glabella in anterior view; sagittal length 50.9% (46.5–55.2) width across posterior border; sagittal length 84.1% (79.2–89.1) width across δ; sagittal length 125.4% (115.2–140.9) width across anterior border furrow; sagittal length 106.1% (97.5–113.8) width (tr.) across γ; width across posterior border 247% (229.2–270.7) width across anterior border furrow; glabella subtrapezoidal in outline, sagittal length 83.4% (71.8–96.4) maximum width (tr.) across L1, moderately strong dorsal inflation, with apex sitting just below that of palpebral lobes in anterior view (e.g., Pl. 8, fig. 7), sculpture of prominent larger tubercles present, especially on median portion of glabella, with background sculpture of coarse granules; L1 clearly developed, bulbous, displaced laterally giving glabella overall bell shape, inner margin not isolated from glabella, deep “C”-shaped furrow composed of S1, axial furrow, and distal portion of LO define external margin of L1; S1 deep, short, directed posteromedially; L2 less well developed than L1, but still prominent, set off anteriorly by extremely short, deep S2; axial furrow narrow and shallow from intersection with posterior cranidial margin to base of L1, deep and laterally deflected around L1, shallower and broad opposite L2 (on most specimens), faint continuation of axial furrow from fossulae anteriorly to intersection with anterior border furrow clearly separates preglabellar field from anterior fixigena, furrows are anteriorly divergent; distance between intersection of axial furrows with posterior cranidial margin 96.9% (91.3–104.0) maximum glabellar width; fossulae deep and pit-like on dorsal surface, ventrally expressed as small raised region; eye ridge poorly developed, oriented obliquely with proximal termination creating an indentation in lateral margin of glabella, defined anteriorly by shallow furrow running from fossulae to γ; preglabellar fur- row incised along entire course, medial portion slightly deeper on some specimens (e.g., Pl. 8, fig. 3), anteriorly arched; preglabellar field relatively long, with sagittal length 12.7% (8.2–16.7) cranidial length, lengthens (exsag.) slightly abaxially, sculpture of densely spaced granules; anterior border furrow moderately short, shallow, lateral portions opposite anterior fixigenae deeper than medial portion opposite anterior glabellar margin, gently anteriorly arched; anterior border in dorsal view longest medially, with sagittal length 14.1% (10.7–17.6) cranidial length (sag.), shorter abaxially with distal portion tapered to a point at intersection with anterior facial suture, anterior margin more strongly anteriorly arched than posterior margin; dorsal inflation weak; anterior border in anterior view strongly dorsally arched (e.g., Pl. 8, fig. 7), thickens nearly equal along entire course, covered with densely spaced granules of medium and small size; lateral profile of preglabellar area forms moderate ventrally sloping surface, slight break in slope at anterior border furrow, with anterior border slightly independently inflated; articulating furrow for rostral plate present ventrally beneath anterior border, broad, forming distinct groove, with posterior and anterior margins defined by distinct inflated rims, anteriorly arched as anterior border; fixigena covered by small to medium densely spaced granules, with few isolated small tubercles (especially on interocular fixigena); interocular fixigena relatively broad; palpebral lobe with length between γ and ε 51.8% (45.0–58.5) glabellar length (sag.), gentle independent inflation, δ situated opposite L2, γ situated opposite point between S2 and fossulae, and ε opposite anterior portion of L1; lobe set off from fixigena by narrow shallow furrow; posterior projection extends far beyond lateral extent of palpebral lobe in dorsal view, strongly downturned from horizontal plane (e.g., Pl. 8, figs 14, 17); narrow inflated ridge continuing from posterior portion of palpebral lobe around anterior margin of posterior fixigena, progressively narrower and weaker toward intersection with posterior border furrow, deep narrow furrow bounds inner margin of ridge opposite point just behind ε; posterior fixigena tapering (exsag.) to a point abaxially, portion distal to fulcrum directed posterolaterally; posterior border furrow distinct, shallow adjacent to axial furrow, lengthening (exsag.) toward fulcrum, deepest at fulcrum, abruptly shallow just before intersection with posterior facial suture so that furrow terminates before reaching intersection; posterior border short (exsag.) adjacent to LO, directed subparallel to transverse axis, gently lengthening abaxially to fulcrum, then significantly longer (exsag.) from fulcrum abaxially, portion distal to fulcrum directed posterolaterally, confluent with genal spine; doublure beneath posterior border subtriangular in outline; genal spine long and stout, directed subparallel to sagittal axis; SO relatively short (sag., exsag.), clearly incised, slightly shallower medially, deepest opposite posterior margin of L1, gently anteriorly arched, merging smoothly around L1 into axial furrow; LO generally lenticular in outline, sagittal length 18.6% (16.7–22.0) cranidial length (sag.), anterior margin anteriorly arched, posterior margin posteriorly arched, with median portion nearly subparallel to transverse axis in some specimens (e.g., Pl. 8, figs 2, 15), median tubercle prominent and elongated, in lateral view tubercle merges smoothly with anterior margin of LO so that an uninterrupted slope is formed, tubercle angled upwards and back in lateral view, in some specimens tubercle appears to be hooked backwards (e.g., Pl. 8, fig. 22); a few small isolated tubercles present along posterior margin of median portion of LO, some specimens exhibit two distinct tubercles flanking larger median tubercle (e.g., Pl. 8, figs 15, 21, Pl. 9, fig. 2), others possess three or four small tubercles situated in an arc along posterior margin (e.g., Pl. 8, fig. 2); LO and median tubercle visible in anterior view sitting just above glabellar apex; doublure present beneath LO broad, terminates before reaching ventral expression of SO, surface largely smooth, with a few scattered very fine granules mostly situated near posterior margin. Librigena (Pl. 12, figs 10, 11, 13, 14, 16–18, 20–28) with maximum width 57.1% (52.6–63.3) exsagittal length (excluding anterior projection); length of anterior portion of facial suture 36.5% (30.6–42.3) exsagittal length of main body, length of posterior facial suture 44.8% (42.3–50.6) exsagittal length of main body; visual surface of eye large; eye socle clearly developed, short, with width less than half that of visual surface, clearly set off from visual surface by narrow distinct furrow;furrow separating eye socle from field broader with width almost equal to that of eye socle, marks distinct change in slope between eye socle and field; field large, subtrapezoidal in outline, moderately inflated sitting above border in lateral view, with sculpture of densely spaced small granules, overlain by small less densely spaced tubercles, sculpture subdued in band adjacent to border furrow; lateral border furrow shallow and nearly effaced at intersection with posterior facial suture, becoming deeper anteriorly, abruptly shallow at intersection with anterior facial suture; lateral border broad in external view, narrowest anteriorly, progressively broader posteriorly from about midlength to posterior facial suture, in lateral view border tall, (e.g., Pl. 13, fig. 26) and gently flexed upward medially, sculpture similar to that on field, with fewer prominent isolated small tubercles, sculpture present on entire external surface; anterior projection short, hook-like; anterior facial suture nearly straight to very gently arcuate across field, strong change in course at intersection with lateral border; posterior projection longer than anterior; posterior facial suture nearly straight to very gently convex across proximal portion of field, becoming concave across distal portion of field and posterior projection, with maximum point of curvature across from field just adjacent to lateral border furrow; broad doublure present beneath lateral border and anterior and posterior projections, portion beneath posterior projection forming small flange that is visible in external view as small subtriangular point (e.g., Pl. 12, fig. 14); doublure with sculpture of very fine granules present along external margin, becoming progressively effaced toward inner margin, narrow inflated ridge-like rim developed along external margin (e.g., Pl. 12, fig. 17, Pl. 13, fig. 24). Hypostome elongate with maximum width achieved across anterior wings; width (tr.) across shoulder 82.7% (80.5–83.9) that across anterior wings; anterior margin forming gently anteriorly bowed curve, cut strongly posterolaterally at anterolateral corner forming obtuse angle; anterior border flattened, broad, strongly flexed ventrally (e.g. Pl. 13, figs 6, 7, 12, 13), with narrow rim developed along anterior margin; anterior border furrow forming, broad depression medially, lateral portions shallower; anterior wing large, posterolateral corner forming nearly right angle in ventral view, flexed dorsally (e.g., Pl. 13, fig. 9); pit of wing process deep ventrally, clearly visible dorsally (Pl. 13, figs 4, 14); hypostome strongly constricted (tr.) just below anterior wing and opposite anterior portion of middle body before shoulder, with lateral margin strongly expanded (tr.) outward around shoul- der, then turning sharply posteromedially toward posterior margin; middle body elongate, with length 138.5% (135.4–142.3) maximum width, anterior margin sloping gently toward anterior border furrow, with only moderate dorsoventral convexity; anterior lobe of middle body with length (sag.) approximately just over twice that of posterior lobe; middle furrow moderately incised, directed posteromedially, deepest abaxially, shallowing medially eventually becoming effaced so that anterior portion of middle body is very faintly isolated; lateral border clearly set off from middle body by distinct lateral border furrow; lateral border furrow with portion anterior to middle furrow deepest, slit-like, directed almost parallel to sagittal axis; lateral border furrow shallower just posterior to intersection with middle furrow, slightly deeper again opposite shoulder; posterolateral corners developed into two distinct posteriorly directed pointed projections (Pl. 13, fig. 3); posterior margin strongly arched medially, forming deep “V” with apex directed anteriorly; posterior border furrow shallow, clearly setting off posterior margin of middle body from posterior border; broad doublure present beneath lateral and posterior borders (Pl. 13, fig. 4), narrow inflated rim developed along inner margin, which forms a broadly rounded “U”. Rostral plate wide (tr.) (Pl. 13, figs 15, 16, 18, 19), relatively short in lateral profile (Pl. 13, fig. 17); border sector wider (tr.) than doublural sector, anterior and posterior margins moderately arched so that border sector forms curved band (Pl. 13, fig. 19), of similar length (sag., exsag.) along majority of band with distal portions opposite connective sutures pinched out; distinct and abrupt change in slope between border and doublural sectors; doublural sector forms curved band similar to border sector, but shorter (sag., exsag.) and slightly concave, similarly shorter opposite connective sutures, but with distal tips more rounded; connective sutures cut strongly obliquely across border and doublural sectors, forming deep “V” with apex pointing medially; scattered coarse granules cover external surface of border sector, especially on distal portion opposite connective suture; external surface of doublural sector more smooth. Thoracic segment (Pl. 13, figs 21–23, 25, 28) with overall strong dorsal convexity (Pl. 13, figs 25, 28), axis strongly convex, pleural region between axis and fulcrum nearly parallel to horizontal plane, and portion distal to fulcrum strongly downturned from horizontal; fulcrum set relatively close to axis; distinct articulating halfring, with sagittal length 72.2% that of axial ring, anterior margin gently anterior arched, posterior margin almost exactly transverse, distal tips forming distinct points; ring furrow incised along entire course with medial portion shallow, distal portion deep and slit-like, medial portion transverse with distal tips directed more anterolaterally; axial ring of similar length (sag. and exsag.) along entire course, with lateral portions directed more anterolaterally and medial portion very gently anteriorly arched; axial furrow shallow; width (tr.) of pleurae in dorsal view 71.5% (68.8–75.0) that of axis (tr.); pleural furrow deeply incised from axial furrow abaxially, abruptly terminated before reaching margin (Pl. 13, fig. 23); anterior and posterior pleural bands of similar length (exsag.), both shortest adjacent to axis, lengthening slightly abaxially; posterior pleural band extended distally into short articulating facet, with distal tip forming distinct, small posterolaterally directed spike, anterior corner of facet developed into short articulating process; semilunate strip of doublure present beneath articulating half-ring (Pl. 13, fig. 22); doublure also present below pleural facet (Pl. 13, fig. 28), continuing along anterior margin of pleurae and terminating at fulcrum (Pl. 13, fig. 22); sculpture of closely spaced granules covers external surface of segment, with additional larger granules present along posterior portion of posterior pleural band. Pygidial measurements made on the most complete specimens of Plates 14 and 15. Pygidium with strong dorso-ventral convexity, sagittal length (excluding articulating half-ring) 55.3% (49.0–63.3) maximum width (tr.); axis with strong independent inflation, composed of articulating half-ring, four clearly defined axial rings, terminated by broadly rounded and inflated terminal piece; maximum axial width (tr.) 37.0% (33.5–40.8) maximum pygidial width; axis gently tapered (tr) posteriorly; posterior margin of axis faintly discernible in dorsal view, more clearly defined in lateral and posterior view by change in slope between terminal piece and pleural region; dorsal surface of axis gently sloping downward toward posterior margin in lateral profile, with articulating half-ring and first axial ring situated highest, axial rings distinct with clear independent inflation; articulating half-ring with sagittal length similar to that of first axial ring, anterior margin gently anteriorly arched, posterior margin nearly transverse (e.g., Pl. 14, fig. 13) to gently anteriorly arched (e.g., Pl. 14, fig. 28), lateral margins pinch out to form distinct points before reaching lateral extent of first axial ring, sculpture of fine granules, prominent paired tubercles absent; first axial ring with sagittal length 14.4% (9.8–17.4) that of pygidium (excluding articulating half-ring), length generally similar across ring, except for slightly shorter distal tips, which appear to merge abaxially into pleural band across a shallow axial furrow on some specimens (e.g., Pl. 14, fig. 13), sculpture of densely spaced granules, overlain by scattered distinct small tubercles (on some specimens, e.g., Pl. 14, fig. 1), with distinct pair of prominent tubercles adjacent to sagittal line (e.g., Pl. 14, fig. 11); second axial ring similar to first, but shorter (sag., exsag.), width (tr.) nearly equal to that of first axial ring, sculpture also similar; third and fourth rings generally similar to first two, progressively smaller; articulating furrow distinct along entire course, nearly transverse to gently anteriorly arched, clearly setting off articulating half-ring from first axial ring; second and third ring furrows deepest and longest (exsag.) abaxially, shallower and shorter (sag.) medially, directed almost exactly transverse medially; subsequent ring furrows similar to previous, but progressively shallower and more effaced; anterior pygidial margin gently sloping posterolaterally from axial furrow to fulcrum, with slight change in course at fulcrum so remainder of margin directed slightly more posteriorly; first pleural furrow clearly incised, portion between axis and fulcrum deep, straight, directed posterolaterally, portion abaxial to fulcrum progressively shallower towards pygidial margin, generally directed posterolaterally with gentle anterolateral arch, terminated before reaching pygidial margin; first interpleural furrow weakly incised (e.g. Pl. 15, fig. 1), difficult to discern on many specimens; subsequent pleural and interpleural furrows progressively effaced; prominent isolated tubercle present on posterior pleural bands at fulcrum (e.g., Pl. 14, figs 11, 12, 15); fulcrum set very close to axis, becoming progressively closer to axis posteriorly; pleural region distal to fulcrum strongly downturned from horizontal plane; sculpture of densely spaced granules covers pleural region, overlain by larger isolated tubercles around and adjacent to pygidial margin; lateral and posterior pygidial margin broadly rounded in dorsal view, in posterior view margin moderately arched upward medially; border not clearly differentiated, in posterior view appears to possess very slight independent inflation, sculpture more dense and finer compared to that of pleural region; doublure short (e.g., Pl. 15, fig. 13), strongly turned upward to ventral surface, covered with sculpture of densely spaced granules, in ventral view inner margin describes broadly rounded and slightly “V” shaped curve. Ontogeny. The glabella on the smallest recovered specimens is elongate and rectangular (e.g., Pl. 12, figs 2, 3) and strongly dorsally inflated. It becomes shorter, broader, and more trapezoidal in outline throughout ontogeny and also less strongly inflated. The genal spine becomes longer relative to the length (sag.) of the cranidium. In the smallest specimens it is about 25–30% as long as the cra, Published as part of Adrain, Jonathan M., Karim, Talia S. & McAdams, Neo E. B., 2020, Atlanticalymene, a new genus of Middle Ordovician (Darriwilian) calymenine trilobites, and revision of the calymenoidean genus Protocalymene Ross, pp. 1-55 in Zootaxa 4859 (1) on pages 17-21, DOI: 10.11646/zootaxa.4859.1.1, http://zenodo.org/record/4537316, {"references":["Ross, R. J., Jr. (1967) Some Middle Ordovician brachiopods and trilobites from the Basin Ranges, western United States. United States Geological Survey Professional Paper, 523 - D, 1 - 43. https: // doi. org / 10.3133 / pp 523 D","Andrawis, S. F., El Afify, F. & El Hameed, A. T. A. (1983) Lower Paleozoic trilobites from subsurface rocks of the Western Desert, Egypt. Neues Jahrbuch fuer Geologie und Palaeontologie, Monatshefte, 1983, 65 - 68.","Geyer, G. (1990) Die marokkanischen Ellipsocephalidae (Trilobita: Redlichiida). Beringeria, 3, 3 - 363.","Hupe, P. (1953 b) Contribution a l'etude du Cambrien inferieur et du Precambrien III de l'Anti-Atlas marocain. Service geologique du Maroc (Rabat), Notes et Memoires, 103, 1 - 402. (for 1952)","Ross, R. J., Jr. (1970) Ordovician brachiopods, trilobites, and stratigraphy in eastern and central Nevada. United States Geological Survey Professional Paper, 639, 1 - 103. https: // doi. org / 10.3133 / pp 639","Loch, J. D. & Ethington, R. L. (2017) An integrated trilobite and conodont biostratigraphy across the base of the Laurentian Whiterockian Series (lower Middle Ordovician) at its stratotype, Whiterock Canyon Narrows, Nevada. Journal of Paleontology, 91, 294 - 317. https: // doi. org / 10.1017 / jpa. 2016.127"]}

Atlanticalymene n. gen. Type species. Atlanticalymene bardensis n. sp., from the Darriwilian Table Cove Formation of western Newfoundland, Canada. Other species. Atlanticalymene n. sp. A (“? Ischyrophyma sp. ind.” of Whittington [1963, p. 50, pl. 6, figs. 13-15]), Shallow Bay Formation (lower Darriwilian), Lower Head, western Newfoundland; Sthenarocalymene sp. indet. of Zhou et al. (2014, p. 114, fig. 56), Yijianfang Formation (Dapingian), Yijianfang, Bachu, northwestern Tarim, Xinjiang, China. Etymology. From the Atlantic Ocean, on the western edge of which the type locality is situated, and the genus name Calymene; gender is feminine. Diagnosis. Glabella long and parallel-sided anterior to L1; L1 well developed and nearly completely isolated; L2 and L3 scarcely developed, S2 faint and barely discernible, S3 not impressed; cranidial anterior border strongly bowed in anterior view; preglabellar area elongate (sag.; exsag.); eye ridge expressed dorsally; palpebral lobe small; sculpture of small to coarse fairly densely scattered tubercles over all skeletal parts except hypostome. Discussion. As noted above, a consensus emerged in the recent literature (Fortey, 1990; Fortey and Droser, 1999; Turvey, 2002) that Middle Ordovician Laurentian calymenoidean species should all be assigned to Protocalymene and that they are unambiguous calymenids. Revision on the basis of new photographs herein demonstrates that a calymenid affinity is true of only a handful of the occurrences (those assigned by Adrain and Fortey [1997] to Sthenarocalymene), and not necessarily true of Protocalymene mcallisteri. The various reports break down into two morphological groups: taxa related to Darriwilian material described in open nomenclature by Whittington (1965) and taxa related to P. mcallisteri. The former collectively represent Atlanticalymene n.gen., whereas the latter, while certainly calymenoidean, are considered below to be of unclear family relationships. The genus diagnosis is complicated by the fact that there is only one well known species, yet the genus is not monotypic. We have included morphological features of the cranidium that are shared between the known occurrences. Features that are known only from A. bardensis are listed in the species diagnosis of that taxon, with the understanding that both diagnoses should potentially be refined if other exoskeletal parts of other species are described. Zhou et al. (2014) assigned a single partial cranidium to the genus Sthenarocalymene, following assignment of Whittington’s (1965) Table Cove Formation specimens by Adrain and Fortey (1997, p. 105). With description of A. bardensis on the basis of abundant silicified material, it no longer appears that assignment to Sthenarocalymene is justified. The type species of Sthenarocalymene, S. lirella Siveter, 1977, is from the Vollen Formation (Sandbian), Oslo-Asker, Norway. The only other reliably assigned species is S. aldonensis (Reed, 1935), from the Superstes Formation (Sandbian) of the Laurentian-affinity Midland Valley Terrane, Scotland (see Tripp, 1976, p. 408, pl. 7, figs 8–12). Some workers (following Holloway [1980] and including, e.g., Edgecombe and Wright [2004], and Lin [2008]) have assigned a large number of Silurian and Devonian species, ranging from the Telychian to Emsian, considering Apocalymene Chatterton and Campbell, 1980, a junior subjective synonym. The basis for this is little more than that these species, some 27 formally named, are taxa which occur in Silurian and Devonian rocks yet lack glabellar buttresses and share a broadly conserved glabellar outline. Others (e.g., Siveter and Chatterton [1996, p. 57]; Edgecombe [2007, p. 60]) have regarded the question as open. Given the large stratigraphic gap between the earliest “ Apocalymene ” (Telychian species such as the Australian Gravicalymene ? vaccina Holloway, 1994) and the species regarded here as Sthenarocalymene (Sandbian), together with the absence of any detailed phylogenetic work on the Siluro-Devonian group, it seems premature at best to assume they together represent a clade and Sthenarocalymene is restricted herein to the two species listed above. Sthenarocalymene lirella is known from an internal mold of an articulated specimen lacking librigenae, an external mold of a cranidium, one well preserved cuticular cranidium, and two internal molds of cranidia. Its similarity to A. bardensis is scant. The younger Baltic species has much larger L1, strongly inflated L2 and L3, strongly incised S2 and clearly visible S3, a bell-shaped versus subparallel sided glabella, and narrower interocular fixigenae. While the pygidium is known only from the internal mold example on the articulated specimen (Siveter, 1977, fig. 12C), it is clearly narrower relative to its length, has axial furrows that are more strongly posteriorly convergent, and lacks the slightly bulbous paired swellings at the posterior of the axis characteristic of A. bardensis. Apart from both clearly being calymenines, there is little morphologically in common between the taxa and nothing that suggests A. bardensis should be assigned to Sthenarocalymene. Sthenarocalymene aldonensis is known only from poorly preserved molds. While difficult to interpret, the morphology of the available specimens seems to match closely that of the coeval S. lirella. One partial external mold of a librigena is known (Tripp, 1976, pl. 7, fig 10), but it is too incomplete to meaningfully compare. Zhou et al.’s (2014, p. 114, fig. 56) “ Sthenarocalymene sp.,” from the Dapingian of Tarim, consists only of a single incomplete cranidium. Its morphology clearly indicates relationship with A. bardensis, as Zhou et al.’s discussion (2014, p. 115) indicates. In particular, it shares the development of L1 as the only prominent, inflated, glabellar lobe, together with an elongate, parallel-sided glabella. The anterior border is broken off so cannot be compared. The interocular fixigenae of the Tarim specimen are much narrower than those of A. bardensis. The specimen is relatively small, and retains expressed juvenile paired fixigenal spines. Zhou et al. (2016, p. 322, fig. 20J, K) described a single partial cranidium from the lower Darriwilian Zhuozishan Formation of Wuhai, Inner Mongolia, as “ Sthenarocalymene sp. indet.” The affinity of this specimen, which consists of an external mold of a glabella, part of an occipital ring, and a small portion of posterior fixigena and posterior border, is difficult to determine. It has strongly inflated L1 and L2, but L1 seems smaller than L2 and laterally contiguous with the glabella, which is unusual for a calymenine. The glabella is also strongly vaulted with the anterior part steeply forwardly sloping. This species does not resemble A. bardensis. Because there is so little morphological information there are many possibilities for its affinity. It could conceivably represent a species similar to “ Calymeninae n. gen. n. sp. ” (below), but alternatively it might not represent a calymenine at all. Atlanticalymene is compared with the Dapingian “ Calymeninae n. gen. n. sp. ” below. Atlanticalymene bardensis has little in common with the three Gondwanan Armorican Floian species from the Montagne Noire assigned by Courtessole et al. (1983) to Platycalymene (P. (P.) pradesensis from the La Maurerie Formation and P. (P.) minervensis and P. (P.) villerembertensis from the St.-Chinian Formation). All are known only from cranidia, which feature non-isolated L1 and strongly impressed S2 and S3. The interocular fixigenae of P. (P.) pradesensis and P. (P.) villerembertensis are very narrow and the eye is in a more anterior position than in A. bardensis., Published as part of Adrain, Jonathan M., Karim, Talia S. & McAdams, Neo E. B., 2020, Atlanticalymene, a new genus of Middle Ordovician (Darriwilian) calymenine trilobites, and revision of the calymenoidean genus Protocalymene Ross, pp. 1-55 in Zootaxa 4859 (1) on pages 7-8, DOI: 10.11646/zootaxa.4859.1.1, http://zenodo.org/record/4537316, {"references":["Zhou, Z. - Y., Yin, G. - Z. & Zhou, Z. - Q. (2014) Ordovician (Darriwilian-early Katian) trilobite faunas of northwestern Tarim, Xinjiang, China. Memoirs of the Association of Australasian Palaeontologists, 46, 1 - 142.","Fortey, R. A. (1990) Ontogeny, hypostome attachment and trilobite classification. Palaeontology, 33, 529 - 576.","Fortey, R. A. & Droser, M. L. (1999) Trilobites from the base of the type Whiterockian (Middle Ordovician) in Nevada. Journal of Paleontology, 73, 182 - 201. https: // doi. org / 10.1017 / S 0022336000027712","Turvey, S. T. (2002) Phylogeny of the Reedocalymeninae (Trilobita): implications for Early Ordovician biogeography of Gondwana. In: Crame, J. A. & Owen, A. W. (Eds.), Palaeobiogeography and Biodiversity Change: the Ordovician and Mesozoic-Cenozoic Radiations. Geological Society Special Publications 194. Geological Society, London, 53 - 68. https: // doi. org / 10.1144 / GSL. SP. 2002.194.01.05","Adrain, J. M. & Fortey, R. A. (1997) Ordovician trilobites from the Tourmakeady Limestone, western Ireland. Bulletin of the Natural History Museum, London, Geology Series, 53, 79 - 115.","Whittington, H. B. (1965) Trilobites of the Ordovician Table Head Formation, western Newfoundland. Bulletin of the Museum of Comparative Zoology, Harvard, 132, 275 - 442.","Siveter, D. J. (1977) The Middle Ordovician of the Oslo Region, Norway, 27. Trilobites of the family Calymenidae. Norsk Geologisk Tidsskrift, 56, 335 - 396. [for 1976]","Reed, F. R. C. (1935) The Lower Palaeozoic trilobites of Girvan. Supplement No. 3. Monographs of the Palaeontographical Society, 88 (400), 1 - 64. https: // doi. org / 10.1080 / 02693445.1935.12035635","Tripp, R. P. (1976) Ordovician trilobites from the basal superstes Mudstones (Ordovician) at Aldons Quarry, near Girvan, Ayrshire. Transactions of the Royal Society of Edinburgh, 69, 369 - 423. https: // doi. org / 10.1017 / S 0080456800015386","Holloway, D. J. (1980) Middle Silurian trilobites from Arkansas and Oklahoma, U. S. A. Part 1. Palaeontographica, Abteilung A, 170, 1 - 85.","Edgecombe, G. D. & Wright, A. J. (2004) Silicified Early Devonian trilobites from Brogans Creek, New South Wales. Proceedings of the Linnean Society of New South Wales, 124, 177 - 188.","Lin, T. - R. (2008) Silurian. In: Z. - Y., Z. & Zhen, Y. - Y. (Eds.), Trilobite Record of China. Science Press, Beijing, pp. 275 - 284.","Chatterton, B. D. E. & Campbell, K. S. W. (1980) Silurian trilobites from near Canberra and some related forms from the Yass Basin. Palaeontographica, Abteilung A, 167, 77 - 119.","Siveter, D. J. & Chatterton, B. D. E. (1996) Silicified calymenid trilobites from the Mackenzie Mountains, northwest Canada. Palaeontographica Abteilung A, 239, 43 - 60.","Edgecombe, G. D. (2007) Acaste (Trilobita: Phacopina) from the Early Devonian of Tasmania. Alcheringa, 31, 59 - 66. https: // doi. org / 10.1080 / 03115510601123627","Holloway, D. J. (1994) Early Silurian trilobites from the Broken River area, north Queensland. Memoirs of the Museum of Victoria, 54, 243 - 269. https: // doi. org / 10.24199 / j. mmv. 1994.54.12","Zhou, Z. - Y., Zhou, Z. - Q. & Yin, G. - Z. (2016) Ordovician trilobites from the uppermost Zhuozishan Formation (early Darriwilian) at Zhuozishan, Wuhai, Inner Mongolia. Memoirs of the Association of Australasian Palaeontologists, 49, 289 - 328.","Courtessole, R., Marek, L., Pillet, J., Ubaghs, G. & Vizcaino, D. (1983) Calymenina, Echinodermata et Hyolitha de l'Ordovicien inferieur de la Montagne Noire (France meridionale). Memoires de la Societe des Etudes Scientifiques de l'Aude, 1983, 1 - 62."]}

Atlanticalymene bardensis n. sp. Plates 1–7 1965 Ischyrophyma? sp. ind.; Whittington, p. 340, pl. 19, figs 16, 19, 20. 1965 Komaspidid? pygidium; Whittington, p. 374, pl. 39, figs 8, 9. 1965 aff. Calymenidius sp. ind.; Whittington, p. 419, pl. 59, figs 10, 12–15. 1967 Protocalymene sp.; Ross, p. D27. 1970 Protocalymene sp.; Ross, p. 92. 1977 Protocalymene sp.; Siveter, p. 388. 1990 Protocalymene sp.; Fortey, p. 568. 1997 Sthenarocalymene sp.; Adrain and Fortey, p. 105. 1999 “aff. Calymenidius sp. ind.” of Whittington; Fortey and Droser, p. 199. 2002 Protocalymene sp.; Turvey, p. 56. 2011 Calymenia sp.; Shaw and Bolton, p. 417. 2014 Sthenarocalymene sp.; Zhou et al., p. 115. 2016 Sthenarocalymene sp.; Zhou et al., p. 322. Material. Holotype, cranidium, GSC 135298 (Pl. 2, figs 10, 13–15), and assigned specimens GSC 135289–135297, 135299–135358, from horizons TCM 13, TCM 14, and TCM 18, Table Cove Formation (Darriwilian), coast opposite Marechal Island, near Main Brook, Hare Bay, Great Northern Peninsula, western Newfoundland. Assigned specimens GSC 18345, 18346, 18369, 18569, Table Cove Formation (Darriwilian), Table Cove, west coast of Great Northern Peninsula, western Newfoundland, Canada. Etymology. From Bard Island Tickle, a local name for the type locality. Diagnosis. Interocular fixigena very broad; librigena subtriangular in outline, posterior facial suture hardly bowed compared with other calymenine taxa; eye small; rostal plate with gently ventrally curved ventral sector, longer exsagittally than sagittally in plan view, smooth and posteriorly concave doublural sector; hypostome with large anterior wings, lacking rhynchos, and with posteromedian spine in addition to the conventional paired posterolateral spines, posterior border long (sag.; exsag.); thoracic segments with anterior and posterior pleural bands subequal in length (exsag.), tuberculate sculpture on both but more prominent on posterior band; pygidium with four distinct axial rings, fourth not fully defined by ring furrow posteriorly in some specimens; pleural furrow of only the first segment well impressed distal to fulcrum; posterior of axis slightly inflated with a pair of subdued lateral swellings in large specimens; pleural region with faint interpleural furrows and dense fine tuberculate sculpture. Description. Cranidial measurements are based on the large, intact specimens of Pl. 1, fig. 10, Pl. 2, figs 1, 2, 10, 12, 16, 18, and Pl. 3, figs 1–3, 12. Where part of the cranidial morphology was preserved on only one side, the distance to the sagittal line from this side was doubled. Cranidium strongly vaulted, covered with densely spaced tubercles that are sometimes flattened; maximum cranidial sagittal length 50.6% (47.5–55.3) maximum width across posterior border; width across anterior border furrow 42.1% (39.1–45.4) maximum width across posterior border; distance across γ 66.5% (61.8–70.9) maximum cranidial width; anterior border with length (sag.) 75.9% (62.7–95.5) LO sagittal length, slightly shorter (exsag.) abaxially, forming strongly bowed arch in anterior profile; anterior border flexed upward and back toward anterior tip of glabella, so that it partially obscures border furrow in anterior view, but it does not abut anterior margin of glabella in transverse profile; anterior border with sculpture of small and medium sized, densely spaced somewhat flattened tubercles, tubercles become smaller toward rostral suture; anterior border furrow confluent with preglabellar furrow, long (sag.), with length (sag.) nearly equal to that of anterior border in dorsal view on some specimens, dorsally concave, much deeper and shorter (exsag.) opposite frontal area; anterior sections of facial sutures gently laterally convex opposite anterior border, laterally concave opposite anterior border furrow, and strongly, but unevenly, laterally bowed opposite frontal areas with bow strongest opposite anterolateral corners of glabella; frontal areas strongly inflated, sloped strongly downward and mostly facing anteromedially with exsagittal portion facing slightly obliquely, anteriormost portion nearly vertical to slightly recurved under cranidium; palpebral lobe small, lobe strongly laterally bowed, comma shaped, with portion posterior to δ slightly longer than portion anterior to δ; distance across γ 131.5% (124.3–142.7) cranidial sagittal length; distinct furrow clearly differentiating palpebral lobe from fixigena, furrow is shallow anteriorly, but deep along posterolateral corner of lobe; eye ridge faint, but discernible on dorsal surface of most specimens, clearly visible ventrally (Pl. 2, fig. 8), running obliquely from anterior portion of palpebral lobe to point just behind fossula; interocular fixigena very broad, with moderately strong dorsal inflation, sloping toward glabella; posterior fixigena with inflation similar to frontal area, strongly sloping downward from horizontal plane; fixigena covered with sculpture of medium and small sized scattered tubercles, tubercles become smaller and less dense toward genal angle; posterior section of facial suture nearly straight, slightly posterolaterally directed to nearly transverse; posterior border furrow relatively long (exsag.) and deep, nearly transverse, deeper and forming a sharp contact posteriorly with posterior border, shallower and forming a more gradational contact anteriorly with posterior fixigena, distal and proximal tips shallower; posterior border dorsally inflated, shortest (exsag.) proximally, lengthened distally from fulcrum, then slightly shortened distally from point opposite distal margin of posterior facial suture; border with fine background tubercles and a few larger tubercles arranged linearly along portion of border between fulcrum and axis; posterior margin of posterior border transversely straight to fulcrum, directed more posterolaterally from fulcrum to point opposite distal margin of posterior facial suture, directed anterolaterally from this point distally; ventral margin of posterior border between fulcrum and axis with narrow transverse articulating groove, additional thin subtriangular strip of doublure present beneath posterior border from fulcrum distally; genal angle developed into very short posterolaterally directed projection; glabella subtrapezoidal in dorsal view, with maximum width across L1 98.8% (87.9–104.1) sagittal length excluding LO, sagittal length (excluding LO) 64.8% (61.9–71.7) that of cranidium, strongly convex and dorsally inflated, with apex sitting above fixigena and situated opposite posterior fixigena in lateral view, anterior portion of glabella faces anteriorly and is nearly recurved under margin; axial furrows clearly impressed along majority of course, shallow and nearly effaced opposite LO, deeper and laterally bowed around L1, furrow broad in front of L1 forming a subtriangular depression along the lateral glabellar margin, tapers anteriorly, but broadens again at intersection with anterior border and preglabellar furrows, width across posterior contact of furrows with posterior margin 58.8% (53.6–63.7) cranidial sagittal length, laterally confluent with posterior bor- der furrow; S1 deep, completely isolating L1 on some specimens (e.g., Pl. 2, fig. 2), but not quite on others (e.g., Pl. 2, fig. 10); S2 poorly developed, barely visible on some specimens; L1 bulbous, subtriangular, with strong dorsal inflation; L2 and L3 not prominent and without independent inflation; sculpture of mostly small densely spaced tubercles covers glabella, with a scattering of larger tubercles superimposed; LO long, sagittal length 36.9% (35.0–40.7) that of cranidium, longer sagittally than exsagittally, anterior and posterior margins nearly transverse medially, with distal tips directed anterolaterally, sculpture of small scattered tubercles, slightly less densely spaced than on glabella, prominent median node, situated slightly anterior to midline; SO deep and short (sag.) medially, with distal tips deeper and deflected around base of L1, nearly transverse medially, anterior and posterior edges with sharp contact with rear of main glabella and LO respectively, joining axial furrow in smooth curve without obvious disruption in course; doublure of broad, semicircular articulating surface underlying LO, anterior margin terminating just before ventral expression of SO, mostly smooth with very faint transverse lines; fossulae expressed dorsally on most specimens. Librigenal measurements were made on the larger specimens of Pl. 4, figs 28–30, 34, 36, Pl. 5, figs 41, 44. Librigena subtriangular, with main body (excluding anterior projection) with maximum width 74.0% (66.7–76.9) exsagittal length; anterior section of facial suture with length 62.0% (55.1–68.3) exsagittal length of main body and posterior section of facial suture with length 53.5% (48.6–59.2) exsagittal length of main body; anterior section gently convex to nearly straight opposite field, with curve slightly more strong opposite abaxial half of field, curve strongly bent across lateral border; posterior section with gentle concave bow, curve continues smoothly across lateral border in some specimens, but in others curve is more strongly bent at lateral border; visual surface small, short, bulbous; eye separated from field by shallow furrow, deeper posteriorly, furrow covered by sculpture of small tubercles; field with background sculpture of very fine granules overlain by more prominent sculpture of densely spaced small and medium sized tubercles; lateral border furrow broad and relatively deep, distal tips slightly shallower on most specimens, background sculpture of fine granules covers furrow, but larger tubercles are mostly absent; lateral border with margin strongly but not evenly arcuate, curve strongest just anterior to midlength; border broad, strongly inflated with margin flattened forming a nearly vertical wall in ventrolateral profile (Pl. 5, figs 42, 43), with sculpture of very densely spaced small flattened tubercles, some slightly larger tubercles are present along the internal margin adjacent to lateral border furrow, ventrolateral margin with prominent raised line bounding margin; anterior projection moderately short, downturned from horizontal plane (Pl. 5, fig. 42), sculpture from border continues without obvious disruption onto anterior projection; doublure broad and slightly narrower than lateral border and anterior projection, narrower posteriorly, strongly upturned toward ventral surface, largely smooth, lacking coarsely tuberculate sculpture present on dorsal surface; inner margin of doublure describes continuous arc, with sharp angular change posteriorly. Rostral plate measurements were made on the four specimens of Plate 5. Rostral plate with width (tr.) at juncture of connective suture and inner arc 52.1% (44.5–60.8) width at rostral suture; length (sag.) of border sector 19.0% (16.7–22.6) maximum width at juncture of connective and rostral sutures, border sector lengthened (exsag.) abaxially; border sector strongly bowed, inner arc tighter than arc along rostral suture, with sculpture of densely spaced, flattened, medium and small sized tubercles; intersection of border and doublural sectors describing smooth arc; doublural sector smooth, lacking obvious tuberculate sculpture, posteriorly concave. Hypostomal measurements were made on the six specimens of Plate 5. Hypostome with anterior border strongly ventrally flexed, forming a short wall along the anterior margin; anterior border furrow deep and incised medially along anterior margin of middle body, otherwise shallow; anterior margin of hypostome describing smooth arc, with medial portion more strongly arched than portion opposite anterior wing; lateral margin somewhat sinuous to nearly straight, but overall directed nearly parallel to sagittal axis; minimum hypostomal width (tr.) across middle body 57.5% (53.8–60.0) maximum hypostomal width across anterior wing; width across shoulder 69.6% (63.8–71.3) width across anterior wing; anterior wing large, extended far beyond lateral extent of shoulder, with subrectangular outline and small pit at posterolateral corner; lateral margin of shoulder directed gently posteromedially toward posterior margin; posterior wing developed into short dorsally directed process; lateral border furrow deep and incised, deeper opposite anterior portion of middle body; lateral border relatively wide (tr.), strongly inflated; posterior bor- der furrow shallow, slightly deeper medially on some specimens, but clearly outlining posterior margin of middle body; posterior border long (sag., exsag.), flattened, extended into three relatively short posteriorly directed spines, held nearly parallel to horizontal plane; portion of posterior margin between spines strongly arched; middle body with moderate inflation, anterior lobe more strongly inflated than posterior lobe, lacking rhynchos; middle furrow generally shallow, but deeper anteriorly and nearly effaced medially, directed strongly posteromedially, forming a “V” or a “U” shape overall, separating middle body into ovate anterior lobe and roughly U-shaped posterior lobe; posterior lobe unevenly arcuate; posterior furrow variably impressed, describing more shallow U-shape than middle furrow (Pl. 5, figs 1, 5, 6, 12, 16); broad doublure present beneath posterior border, continues along hypostomal margin beneath posterior and lateral portion of shoulder; sculpture of fine granules covers entire ventral surface of hypostome; maculae indistinct. Thorax known from three segments with the following morphology: axial ring with maximum width (tr.) 35.8% (34.4–38.3) maximum width of segment; axial ring with a band of medium and small sized tubercles, band located posteriorly on larger segments; narrow and deep ring furrow, with distal tips longer (exsag.); articulating half ring moderately large, lenticular to crescentic in outline, covered by small densely spaced granules; axial furrows very shallow to effaced; pleural furrow deep and long (exsag.) between axis and fulcrum, slightly shorter from fulcrum abaxially to facet, furrow continues a short distance onto facet, but does not reach margin; anterior and posterior pleural bands of nearly similar length (exsag.), with posterior band slightly longer (exsag.) on larger segment (Pl. 5, fig. 25); band of prominent tubercles present on axial ring continues across posterior pleural band as a single row of tubercles, tubercles continue around lateral margin of pleurae (Pl. 5, figs 27–29); anterior band with less prominent row of small tubercles along posterior margin; anterior and posterior bands with background sculpture of fine densely spaced granules; very narrow, transverse furrow set anterior to anterior band between axis and fulcrum, with the anterior edge of the articulating flange forming a very narrow transverse tongue which articulates with a narrow ventral transverse groove beneath the posterior edge of the pleurae of the next segment anteriorly (or the posterior border of the cranidium); anterolateral tip of posterior pleural band developed into broad facet, subtriangular in plan view with anterolateral corner developed into short point, rounded and lobate in lateral profile; very small axial process, that appears to be a continuation of the abaxial tip of the axial ring, set at the anterior end of the axial furrow articulates with a small pit in the posterior end of the next segment anteriorly (or the posterior of the cranidium); ventrally, doublure forms a broad articulating surface beneath the axial ring, small portion of doublure is also present along posterior margin of the posterior pleural band from the fulcrum distally; fulcrum set far distally, with portion of pleurae distal to fulcrum in transverse profile just slightly longer than portion between fulcrum and axis; portion of pleura distal to fulcrum turned down from horizontal plane between 55-65 degrees, portion of pleurae between fulcrum and axis nearly parallel to horizontal plane to just slightly inclined toward axis. Pygidial measurements were made on the largest and most complete specimens of Pl. 6, figs 1–3, 13, 15, 16, 26. Distance to sagittal line was doubled where one side of the pygidium was broken. Pygidium with maximum width across anterior margin of fourth segment 178.5% (163.4–194.2) sagittal length; axis of four segments and terminal piece, with width across first segment 32.9% (28.1–36.4) maximum pygidial width, width across fourth segment 77.9% (70.0–93.9) width across first segment, length of axis excluding articulating half ring 78.7% (74.3–82.0) total sagittal length of pygidium; articulating half ring semilunate, slightly smaller than first axial segment, sagittal length 11.5% (10.7–12.4) total pygidial length, anterior margin subsemicircular, ring held almost horizontal to sagittal profile of axis, weakly dorsally convex in sagittal profile, strongly bowed in transverse profile (along with rest of axis), with sculpture of very small tubercles; articulating furrow deep, short, and moderately strongly anteriorly bowed; first ring furrow as deep as first, very slightly more transverse; second ring furrow very shallow medially but with distal tips deep, nearly transverse to describing gently anteriorly concave arc; third ring furrow shallow, mostly effaced medially, describing more strongly anteriorly concave arc; first axial ring longer sagittally than exsagittally, with sculpture of about five to six tubercles oriented linearly (tr.) just anterior to mid-length of segment, background sculpture of fine closely spaced granules; posterior rings progressively smaller, but with essentially the same morphology; axis terminated by broad, lightly inflated terminal piece, poorly developed into two lateral swellings in larger specimens (Pl. 6, figs 1–3), densely tuberculate; axis distinctly terminated by change in slope and shallow furrow; axial furrow shallow opposite first axial segment, deepest opposite second and third segments, remaining deep opposite anterior portion of fourth segment, but shallower opposite posterior portion of fourth segment and terminal piece; first segment with maximum exsagittal pleural length 23.6% (21.6–24.7) sagittal axial length, anterior margin almost exactly transversely straight to fulcrum, which is set extremely close to axis, margin directed sharply posterolaterally distal to fulcrum; anterior pleural band set off from margin by very faint transverse accessory furrow (Pl. 6, fig. 10), well inflated, with sculpture of small tubercles arranged linearly along posterior margin of band, background sculpture of fine granules, band of similar length (exsag.) along entire course; posterior pleural band of similar length (exsag.) as anterior band, but slightly longer distally, with mixture of medium and smaller sized tubercles scattered across entire band, slightly more densely spaced distally, finer background tubercles less prominent; pleural furrow deep from axis, past fulcrum, to point just before lateral margin, short (exsag.), terminated before pygidial margin; interpleural furrow much shallower than pleural furrow, deepest between axis and fulcrum, shallower from fulcrum abaxially, extending to pygidial margin; subsequent pleural and interpleural furrows progressively shallower, but remaining deep and discernible a, Published as part of Adrain, Jonathan M., Karim, Talia S. & McAdams, Neo E. B., 2020, Atlanticalymene, a new genus of Middle Ordovician (Darriwilian) calymenine trilobites, and revision of the calymenoidean genus Protocalymene Ross, pp. 1-55 in Zootaxa 4859 (1) on pages 9-13, DOI: 10.11646/zootaxa.4859.1.1, http://zenodo.org/record/4537316, {"references":["Chatterton, B. D. E., Siveter, D. J., Edgecombe, G. D. & Hunt, A. S. (1990) Larvae and relationships of the Calymenina (Trilobita). Journal of Paleontology, 64, 255 - 277. https: // doi. org / 10.1017 / S 0022336000018424","Whittington, H. B. (1965) Trilobites of the Ordovician Table Head Formation, western Newfoundland. Bulletin of the Museum of Comparative Zoology, Harvard, 132, 275 - 442."]}

Protocalymene Ross, 1967 Type species. Protocalymene mcallisteri Ross, 1967, from the Antelope Valley Formation (Dapingian) of California, USA. Other species. Protocalymene sp. of Ross (1970, p. 92, pl. 18, figs 2–5), Antelope Valley Formation, Ike’s Canyon, Monitor Range, Nye County, Nevada; Protocalymene sp. of Loch and Ethington (2017, p. 310, fig. 13.6), uppermost Ninemile Formation, Whiterock Canyon Narrows, Monitor Range, Nye County, Nevada. Diagnosis. Frontal and preglabellar area long and uninflated; anterior border furrow shallow; anterior bor- der not strongly dorsally inflated; L1 prominent, displaced laterally so glabella bell-shaped in outline; L2 well inflated; glabella with lateral indentation in front of L2 where faint oblique eye ridge runs into axial furrow from anterior part of palpebral lobe; median occipital node prominent; cranidial sculpture of medium sized tubercles; posterior projections prominent, bearing robust and long, posteriorly-directed genal spines; hypostome with ventrally smooth middle body and large, triangular posterior spines; librigena with nearly straight anterior and posterior sections of the facial suture, visual surface set atop independently inflated band of socle; pygidium with four axial rings discernible in most specimens, often with larger pair of tubercles on each ring; pygidium relatively narrow, each posterior pleural band with prominent tubercle at fulcrum. Discussion. Whittington (1971, p. 456) excluded Protocalymene from his discussion of calymenid taxonomy “because of the difficulty in determining the systematic position of the small specimens on which it is based.” Similarly, Fortey and Droser (1999, p. 197) noted that Ross’s (1967) illustrated material was all “rather small”. This is true, but in light of our new collections it appears that this is because the species reached a diminutive maximum size. Our new silicified collections contain thousands of trilobite sclerites and P. mcallisteri is one of the most common species. The largest cranidia we have recovered are only about 3.3 mm in sagittal length (e.g., Pl. 8, figs 1, 3). There is no reason to suspect the silicified sample is inherently biased toward lack of preservation of larger specimens. Specimens belonging to a species of the pliomerid Ectenonotus Raymond, 1920, for example, are common. Many cranidia of this species have been recovered that are as large or larger than the single calcareous cranidium assigned by Fortey and Droser (1996, fig. 16.3, 16.6, 16.7) to their new E. progenitor. These specimens are more than double the size of the largest P. mcallisteri cranidia. Given that the species are of broadly similar general morphology, it is likely also that hydrodynamic sorting can be ruled out as an explanation for the small maximum size of P. mcallisteri material. Very large illaenid specimens are also common in the collections. Protocalymene mcallisteri appears simply to have been a small trilobite. In addition to the species noted above, Ross (1972, p. 14) listed “ Protocalymene sp.” from the Antelope Valley Formation above the massive bioherm at Meiklejohn Peak, Nye County, Nevada. This occurrence has not been illustrated. Almost all previous commentators have treated Protocalymene as Calymenidae, and often as Calymeninae (=Flexicalymeninae; see above) (Fortey, 1975, p. 346; Hammann, 1983, p. 46; Fortey, 1990, p. 568; Fortey and Droser, 1999, p. 197; Jell and Adrain, 2003, pp. 431, 468; Loch and Ethington, 2017, p. 310), and as detailed above there has been repeated confusion of Ross’s taxon with the material described by Whittington (1965) in various open nomenclature assignments and formalized here as Atlanticalymene bardensis. The latter, as argued above, is an unambiguous calymenine calymenid. The affinity of Protocalymene is much less clear.A few authors have regarded Protocalymene as of less certain affinity. Kobayashi and Hamada (1977, pp. 124–125), for example, questionably assigned it to a calymenid Subfamily Ptychometopinae Balašova in Černyševa, 1960, along with Ptychometopus Schmidt, 1894, and Endocrania Kobayashi, 1956. Ptychometopus is variably considered either a pharostomatid (e.g., Jell and Adrain, 2003, pp. 436, 476) or a calymenid (e.g., Fortey and Cocks, 2003, p. 267). Endocrania is a junior subjective synonym of the leiostegiid Leiostegium Raymond, 1913 (Zhou and Fortey, 1986, p. 172). Although it has been regarded as a calymenine, few aspects of the morphology of P. mcallisteri resemble members of this subfamily. In particular, the species has a “normal” preglabellar area and anterior border. In most calymenids, the frontal regions are inflated and the preglabellar field is lost, with a more or less inflated anterior border abutting the front of the glabella. This morphology is reminiscent of that of some species of pharostomatids, such as Pharostoma narinosum Siveter, 1977 (fig. 3A–H). Protocalymene mcallisteri does not appear to be a pharostomatid, however, as species of that group have a posterior facial suture which cuts the anterior border adaxial to the genal spine, with the genal spine positioned on the librigena. In all other calymenoideans the genal spine is on the cranidium, and the posterior facial suture cuts the lateral border, not the posterior border. This is emphatically the case in P. mcallisteri, which has huge genal spines developed on the cranidium. These spines themselves are unusual features in a calymenoidean. Some bathycheilids have large and long genal spines (e.g., Bathycheilus gallicus Dean, 1965) but, again, these are librigenal, not cranidial features. Protocalymene mcallisteri does not resemble species of Reedocalymeninae or Colpocoryphinae, all of which have prominent adaptations for coaptation which P. mcallisteri entirely lacks. Despite its unusual morphology, P. mcallisteri has unmistakably calymenoidean features. The rostral plate (Pl. 13, figs 15, 16, 18, 19) is typically calymenoidean, with a border sector and a doublural sector. The hypostome (Pl. 13, figs 1–3) is of typical calymenoidean aspect, with a pair of large posterior spines. The librigena is slightly odd looking due to its nearly straight facial sutures, but it is once again of standard calymenoidean form. In the absence of any obvious close comparisons, but equally obvious calymenoidean affinity, for the time being we elect not to make a family assignment of the genus., Published as part of Adrain, Jonathan M., Karim, Talia S. & McAdams, Neo E. B., 2020, Atlanticalymene, a new genus of Middle Ordovician (Darriwilian) calymenine trilobites, and revision of the calymenoidean genus Protocalymene Ross, pp. 1-55 in Zootaxa 4859 (1) on pages 16-17, DOI: 10.11646/zootaxa.4859.1.1, http://zenodo.org/record/4537316, {"references":["Ross, R. J., Jr. (1967) Some Middle Ordovician brachiopods and trilobites from the Basin Ranges, western United States. United States Geological Survey Professional Paper, 523 - D, 1 - 43. https: // doi. org / 10.3133 / pp 523 D","Ross, R. J., Jr. (1970) Ordovician brachiopods, trilobites, and stratigraphy in eastern and central Nevada. United States Geological Survey Professional Paper, 639, 1 - 103. https: // doi. org / 10.3133 / pp 639","Loch, J. D. & Ethington, R. L. (2017) An integrated trilobite and conodont biostratigraphy across the base of the Laurentian Whiterockian Series (lower Middle Ordovician) at its stratotype, Whiterock Canyon Narrows, Nevada. Journal of Paleontology, 91, 294 - 317. https: // doi. org / 10.1017 / jpa. 2016.127","Whittington, H. B. (1971) Silurian calymenid trilobites from the United States, Norway and Sweden. Palaeontology, 14, 455 - 477.","Fortey, R. A. & Droser, M. L. (1999) Trilobites from the base of the type Whiterockian (Middle Ordovician) in Nevada. Journal of Paleontology, 73, 182 - 201. https: // doi. org / 10.1017 / S 0022336000027712","Raymond, P. E. (1920) Some new Ordovician trilobites. Bulletin of the Museum of Comparative Zoology, Harvard, 64, 273 - 296.","Fortey, R. A. & Droser, M. L. (1996) Trilobites at the base of the Middle Ordovician, western United States. Journal of Paleontology, 70, 73 - 99. https: // doi. org / 10.1017 / S 002233600002312 X","Ross, R. J., Jr. (1972) Fossils from the Ordovician bioherm at Meiklejohn Peak, Nevada. United States Geological Survey Professional Paper, 685, 1 - 47. https: // doi. org / 10.3133 / pp 685","Fortey, R. A. (1975) Early Ordovician trilobite communities. Fossils and Strata, 4, 331 - 352.","Hammann, W. (1983) Calymenacea (Trilobita) aus dem Ordovizium von Spanien; ihre Biostratigraphie, Okologie und Systematik. Abhandlungen der Senckenbergischen Naturforschenden Gesellschaft, 542, 1 - 177.","Fortey, R. A. (1990) Ontogeny, hypostome attachment and trilobite classification. Palaeontology, 33, 529 - 576.","Jell, P. A. & Adrain, J. M. (2003) Available generic names for trilobites. Memoirs of the Queensland Museum, 48, 331 - 553.","Whittington, H. B. (1965) Trilobites of the Ordovician Table Head Formation, western Newfoundland. Bulletin of the Museum of Comparative Zoology, Harvard, 132, 275 - 442.","Kobayashi, T. & Hamada, T. (1977) Devonian trilobites of Japan in comparison with Asian, Pacific and other faunas. Special Papers of the Palaeontological Society of Japan, 20, 1 - 202.","Cernyseva, N. E. (1960) [Trilobita]. In: Orlov, U. A. (Ed.), Osnovy paleontologii; spravocnik dla paleontologov i geologov SSSR. 8. Clenistonogie, trilobitoobraznye i rakoobraznye. Akademia Nauk SSSR, Moscow, pp. 17 - 194. [in Russian]","Schmidt, F. (1894) Revision der ostbaltischen silurischen Trilobiten. Abteilung IV: Calymmeniden, Proetiden, Bronteiden, Harpeiden, Trinucleiden, Remopleuriden und Agnostiden. Memoires de l'Academie Imperiale des Sciences de St. - Petersbourg, VII'e Serie, 42 (5), 1 - 93.","Kobayashi, T. (1956) On the Kaolishaniinae. Japanese Journal of Geology and Geography, 27, 9 - 20.","Fortey, R. A. & Cocks, L. R. M. (2003) Palaeontological evidence bearing on global Ordovician-Silurian continental reconstructions. Earth-Science Reviews, 61, 245 - 307. https: // doi. org / 10.1016 / S 0012 - 8252 (02) 00115 - 0","Raymond, P. E. (1913) A revision of the species which have been referred to the genus Bathyurus. Bulletin of the Victoria Memorial Museum, 1, 51 - 69. https: // doi. org / 10.4095 / 104944","Zhou, Z. - Y. & Fortey, R. A. (1986) Ordovician trilobites from north and northeastern China. Palaeontographica, Abteilung A, 192, 157 - 210.","Siveter, D. J. (1977) The Middle Ordovician of the Oslo Region, Norway, 27. Trilobites of the family Calymenidae. Norsk Geologisk Tidsskrift, 56, 335 - 396. [for 1976]","Dean, W. T. (1965) A revision of the Ordovician trilobite genus Bathycheilus Holub. Sbornik Narodniho Muzea v Praze. Rada B. Prirodni Vedy, 21, 1 - 10."]}

Subfamily Calymeninae Milne Edwards, 1840 =Flexicalymeninae Siveter, 1977 Discussion. Siveter (1977) restricted Calymeninae to those taxa with fixigenal buttresses to the glabellar lobes and assigned the remainder of taxa to his new Flexicalymeninae. While it appears likely that Calymeninae as thus restricted is monophyletic (though the concept has never been explored analytically), it is equally apparent that Flexicalymeninae is expressly paraphyletic, a grade left over by removal of Calymeninae. Hence we elect not to formally recognize it and follow Adrain (2013, pp. 309–310) in regarding all of the taxa in question as Calymeninae. The early history of putative members of the subfamily Calymeninae Milne Edwards, 1840, is sparsely known. Three formally named species are known from the Floian, all from Gondwanan Armorica and assigned to Platycalymene Shirley, 1936, by Courtessole et al. (1983). No named calymenine species are known from the Dapingian, and nine occur globally in the Darriwilian. The subfamily became increasingly more common thereafter and at least 58 Katian species have been named. No potential Floian calymenines have been reported from Laurentia, but several Dapingian and lower Darriwilian occurrences have been described, though not always recognized as such. These are assigned herein to an unnamed, monotypic, new Dapingian genus and to the Darriwilian Atlanticalymene n. gen. (to which a Dapingian species from Tarim is also tentatively assigned)., Published as part of Adrain, Jonathan M., Karim, Talia S. & McAdams, Neo E. B., 2020, Atlanticalymene, a new genus of Middle Ordovician (Darriwilian) calymenine trilobites, and revision of the calymenoidean genus Protocalymene Ross, pp. 1-55 in Zootaxa 4859 (1) on page 7, DOI: 10.11646/zootaxa.4859.1.1, http://zenodo.org/record/4537316, {"references":["Milne Edwards, H. (1840) Histoire naturelle des Crustaces, comprenant l'anatomie, la physiologie et la classification de ces animaux. Vol. 3. Roret, Paris, 638 pp.","Siveter, D. J. (1977) The Middle Ordovician of the Oslo Region, Norway, 27. Trilobites of the family Calymenidae. Norsk Geologisk Tidsskrift, 56, 335 - 396. [for 1976]","Adrain, J. M. (2013) A synopsis of Ordovician trilobite distribution and diversity. In: Harper, D. A. T. & Servais, T. (Eds.), Early Palaeozoic Biogeography and Palaeogeography. Geological Society, London, Memoirs, 38, pp. 297 - 336. https: // doi. org / 10.1144 / M 38.20","Shirley, J. (1936) Some British trilobites of the family Calymenidae. Quarterly Journal of the Geological Society of London, 92, 384 - 422. https: // doi. org / 10.1144 / GSL. JGS. 1936.092.01 - 04.19","Courtessole, R., Marek, L., Pillet, J., Ubaghs, G. & Vizcaino, D. (1983) Calymenina, Echinodermata et Hyolitha de l'Ordovicien inferieur de la Montagne Noire (France meridionale). Memoires de la Societe des Etudes Scientifiques de l'Aude, 1983, 1 - 62."]}