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The Early Ordovician (late Tremadocian; Stairsian) trilobite Gonioteloides Kobayashi has long been known from a small number of pygidia assigned to a single formally named species, and its affinities have not been assessed. Silicified material from western Utah and southeastern Idaho includes six distinct species assigned to the genus, one of which is the type species. Two others (G. moffitti and G. pankowskii) are new and formally named. An additional three species that are clearly new but known from sparse material are described in open nomenclature. Gonioteloides has a stratigraphic distribution through five consecutive trilobite zones in the mid-Stairsian Stage (upper Tremadocian). Although exoskeletal morphology of three species is almost completely known, the phylogenetic affinity of the taxon remains difficult to determine. It is tentatively assigned to Dimeropygidae Hupé.UUID: http://zoobank.org/23257d6c-262b-4ef5-ae4e-cc431777e67e

New, distinctive, well-preserved and previously undescribed constituents of a Middle Ordovician (middle Darriwilian, Dw2) radiolarian assemblage from the Table Cove Formation in Newfoundland are described. Three-dimensional X-ray micro-computed tomography (μ-CT) facilitates detailed examination of key specimens revealing hitherto unknown details of the internal morphologies of key lower Paleozoic taxonomic groups, among which a lack of knowledge has previously impeded resolution of higher taxonomic rankings.Twenty-seven archaeospiculid and entactinarian taxa are described and illustrated including six new species: Westernbrookia polygonata n. sp., Neopalaeospiculum piccadilliensis n. sp., Ramuspiculum laxum n. sp. Spongentactinia nazarovi n. sp., Aspiculum irregulare n. sp., and Nyfrieslandia ramosissima n. sp. The investigation extends the known ranges of the species: Pararcheoentactinia reedae Won and Iams, 2002; Sphaeroentactinia robusta Won and Iams, 2015; Varispiculum ectospiculatum Won and Iams, 2015; and Svalbardospiculum multifurcatum (Won, Iams, and Reed, 2005), together with the genus Echidnina to the mid-Darriwilian.UUID: http://zoobank.org/74826b7b-bb86-45d5-ad23-e6e65e0706df.

Calcified cyanobacteria are of considerable research value for reconstructing the ecology of Paleozoic and Mesozoic benthic communities on carbonate platforms due to their ability to produce oxygen and fix nitrogen and CO2. The diversity and abundance of calcified cyanobacteria was initially suggested to have declined in the Middle and Late Ordovician, although more recent work suggests that complex and diverse assemblages persisted throughout the Ordovician. Here, calcified cyanobacteria and associated microfossil flora from the Middle and Late Ordovician of the Ordos Basin, North China Block, are systematically described for the first time based on 1330 thin sections from seven outcrop profiles and four drill cores. In total, there are 18 species belonging to 16 genera, including a new species,Proaulopora ordosian. sp.Girvanella,Subtifloria,Acuasiphonoria,Xianella, and Oscillatoriaceae gen. indet. are assigned to Osillatoriales of cyanobacteria;Ortonella,Hedstroemia,Cayeuxia,Zonotrichites,Proaulopora, andPhacelophytonare assigned to Nostocales of cyanobacteria; andGarwoodia,Renalcis,Izhella,Rothpletzella, andWetheredellaare assigned to calcified Microproblematica. A literature survey of Ordovician microfloral assemblages shows that cyanobacteria and associated microfossils occur in reef, open platform, lagoon, and tidal facies. Most genera occur on at least two independent blocks, and many have a cosmopolitan distribution in similar sedimentary facies. Our research suggests that calcified cyanobacteria and associated microfossils formed complex ecosystems and played greater ecological roles on carbonate platforms during the late Middle and Late Ordovician than was previously thought.UUID:http://zoobank.org/1812ccf8-136c-4cff-92ba-faeaf06523ef

The lower strata of the Umachiri Formation from the Altiplano of southeast Peru have yielded a brachiopod-dominated assemblage, containing representatives of the brachiopod superfamilies Polytoechioidea, Orthoidea, and Porambonitoidea, as well as subsidiary trilobite and echinoderm remains. Two new polytoechioid genera and species,Enriquetoechia umachiriensisnew genus new species andAltiplanotoechia hodginin. gen. n. sp. Colmenar in Colmenar and Hodgin, 2020, and one new species,Pomatotrema laubacherin. sp., are described. The presence ofPomatotremain the Peruvian Altiplano represents the occurrence at highest paleolatitude of this genus, normally restricted to low-latitude successions from Laurentia and South China. Other polytoechioids belonging toTritoechia(Tritoechia) andTritoechia(Parvitritoechia) also occur. Identified species of orthoids from the generaParalenorthis,Mollesella, andPanderina? occur in the Peruvian Cordillera Oriental and in the Argentinian Famatina Range. The only porambonitoid represented is closely related toRugostrophia latireticulataNeuman, 1976 from New World Island, interpreted as peri-Laurentian. These brachiopod occurrences indicate a strong biogeographic affinity of the Peruvian Altiplano with the Famatina and western Puna regions, suggesting that the brachiopod faunas of the Peruvian Altiplano, Famatina, and western Puna belonged to a well-differentiated biogeographical subprovince during the Early–Middle Ordovician on the margin of southwestern Gondwana. Links with peri-Laurentian and other low-latitude terranes could be explained by island hopping and/or continuous island arcs, which might facilitate brachiopod larvae dispersal from the Peruvian Altiplano to those terranes across the Iapetus Ocean. Brachiopods from the lower part of the Umachiri Formation indicate a Floian–?Dapingian age, becoming the oldest Ordovician fossils of the Peruvian Altiplano.UUID:http://zoobank.org/9670a000-260d-4d75-9261-110854c7afb8

The Brechin Lagerstätte of southern Ontario contains an exceptionally diverse and well-preserved Late Ordovician (Katian) crinoid fauna. We describe four genera and eight species of camerate crinoids from the Brechin Lagerstätte, including six new species. Consequently, the total diversity of the fauna now stands at 27 genera and 39 nominal species, thereby making it the most taxonomically diverse Ordovician crinoid fauna known. Taxa described include the diplobathrid Pararchaeocrinus kiddi new species and the monobathrids Glyptocrinus ramulosus Billings, 1856, Periglyptocrinus priscus (Billings, 1857a), Periglyptocrinus astricus new species, Periglyptocrinus kevinbretti new species, Periglyptocrinus mcdonaldi new species, Periglyptocrinus silvosus new species, and Abludoglyptocrinus steinheimerae new species. We summarize the taxonomic composition, diversity, and abundance distribution of all known crinoids from the Brechin Lagerstätte to better characterize the paleoecological structure and complexity of the community. We establish that the fauna is dominated by the subclass Pentacrinoidea, both in terms of abundance and species richness. In addition, we analyze species-level abundance data using Relative Abundance Distribution (RAD) models to evaluate the ecological complexity of the paleocommunity. We found that community structure of the Brechin Lagerstätte is best explained by an ecologically ‘complex’ RAD model, which suggests that species partitioned niches along multiple resource axes and/or the presence of multiple ecological ways of life. These results indicate that the Brechin Lagerstätte is significant not only for being the most taxonomically diverse Katian crinoid assemblage, but also for being an early ecologically complex fauna that developed in the wake of the Great Ordovician Biodiversification Event.UUID: http://zoobank.org/f86582ed-5db6-469E-befe-34b801f9a113

Three new Llandovery (early Silurian) crinoids from Estonia provide an improved understanding of the paleogeographic aspects of the crinoid diversification following the end-Ordovician extinctions. The new taxa areEuspirocrinus hintsaenew species (Rhuddanian eucladid),Oepikicrinus perensaenew genus new species (Aeronian camerate), andRozhnovicrinus isakaraenew genus new species (Aeronian eucladid). This brings the total of described Llandovery crinoids in Estonia to eight nominal species and a further three taxa in open nomenclature. The Rhuddanian radiation in Baltica mirrored that on Laurentia and Avalonia and was dominated by Ordovician clades that continued to diversify during the Silurian. Known Aeronian crinoids from Estonia continue these clades, whereas new clades diversified on Laurentia and Avalonia. However, by the Wenlock, a largely cosmopolitan fauna existed on Laurentia, Avalonia, and Baltica.UUID:http://zoobank.org/b5e613f1-c211-4676-8967-5a38a7d8d40e

The order Intejocerida is an enigmatic, short-lived cephalopod taxon known previously only from Early–Middle Ordovician beds of Siberia and the United States. Here we report a new genus,Cabaneroceras, and a new species,C. aznari, from Middle Ordovician strata of central Spain. This finding widens the paleogeographic range of the order toward high-paleolatitudinal areas of peri-Gondwana. A curved conch, characteristic for the new genus, was previously unknown from members of the Intejocerida.UUID:http://zoobank.org/21f0a09c-5265-4d29-824b-6b105d36b791

End-Ordovician extinctions had a profound effect on shallow-water benthic communities, including the Crinoidea. Further, recovery after the extinctions resulted in a macroevolutionary turnover in crinoid faunas. Anticosti Island is the most complete Ordovician-Silurian boundary section recording shallow-water habitats. Both new taxa and changes in Anticosti Island stratigraphic nomenclature are addressed herein. New taxa includeBecsciecrinus groulxin. sp.,Bucucrinus isotaloin. sp.,Jovacrinus clarkin. sp.,Plicodendrocrinus petrykin. sp.,Plicodendrocrinus martinin. sp.,Thalamocrinus daoustaen. sp., andLateranicrinus saintlaurentin. gen. n. sp. The status ofXenocrinus rubusas a boundary-crossing taxon is confirmed, range extensions of several taxa are documented, and the distribution of crinoids with the revised stratigraphic nomenclature is documented.UUID:http://zoobank.org/19613a44-ec69-47d7-88ab-fcf88ba771f0.

The Upper Ordovician Sandbian to Katian strata from the East Qilianshan (northeastern Tibet Plateau) bear a graptolite fauna of moderately high diversity. Graptolites from theAmplexograptus maxwellibeds to theAppendispinograptus longispinusBiozone (Sa2–Ka4 intervals) proposed herein include 27 species of 13 genera. This important graptolite fauna is first described herein although it was initially reported in 1963. Most of them occur in theA. longispinusBiozone corresponding to theDicellograptus complexustoParaorthograptus pacificusbiozones of the Wufeng Formation in the Yangtze region.Alulagraptusnew genus is established based on the materials from the East Qiqiaogou section. The endemic species, e.g.,Alulagraptus ensiformis(Mu and Zhang in Mu et al., 1963),Dicellograptus sinicusMu and Zhang in Mu et al., 1963, andClimacograptus?papilioMu and Zhang in Mu et al., 1963, could indicate that East Qilianshan block was separated from South China.UUID:http://zoobank.org/84ab69a2-0b56-4ec3-912e-730da08ab10a

Actinocerid nautiloids from the Lhasai Formation in the Xainza region are studied systematically for the first time. The nautiloids are identified as Middle Ordovician in age based on stratigraphic correlations with those from North China, Sibumasu, North Australia (northern Gondwana), and North America (Laurentia). A cluster analysis shows strong affinities between the actinocerid nautiloids of the Lhasa Terrane and those of the Himalaya, North China, and Sibumasu terranes. Our results support Middle Ordovician paleogeographic reconstructions that place North China rather than South China much closer to Australia. Nine species assigned to six genera of Meitanoceratidae, Wutinoceratidae, Armenoceratidae, Ormoceratidae, and Discoactinoceratidae are described in detail:Pomphoceras nyalamense(Chen, 1975),Pomphoceras yaliense(Chen, 1975),Wutinocerascf.W.foerstei(Endo, 1930),Mesowutinoceras giganteumChen in Chen and Zou, 1984,Armenoceras tani(Grabau, 1922),Armenoceras teichertiEndo, 1932,Armenoceras xizangensenew species,Deiroceras globosomZou and Shen in Chen and Zou, 1984, andDiscoactinocerascf.D.multiplexumKobayashi, 1927.UUID:http://zoobank.org/ba851fea-e107-4754-a0f4-a70744e325ab

The Upper Ordovician (lower Katian) Bobcaygeon and Verulam formations from the Lake Simcoe region of Ontario contain a highly diverse echinoderm assemblage that is herein recognized as a Konservat-Lagerstätte. Although fossil crinoids have long been recognized from these formations, the fauna has not received a comprehensive taxonomic evaluation since Springer’s classic 1911 monograph. Recent extensive collection and preparation of new material from the Bobcaygeon and Verulam formations near Brechin, Ontario recovered numerous exceptionally preserved crinoid specimens with arms, stems, and attachment structures intact. The Brechin Lagerstätte is the most taxonomically diverse Katian crinoid fauna, with more than 20 crinoid genera represented in this collection.Here, all dicyclic crinoids belonging to subclass Camerata from the Brechin Lagerstätte are evaluated. The following four genera and seven species are described from the fauna, including one new genus and four new species:Reteocrinus stellaris,Reteocrinus alveolatus,Archaeocrinus sundayaen. sp.,Archaeocrinus maraensisn. sp.,Priscillacrinus elegansn. gen. n. sp.,Cleiocrinus regius, andCleiocrinus lepidotusn. sp. The exceptional preservation of this collection provides an opportunity to describe more fully the morphologic and ontogenetic details of known Ordovician crinoid taxa, to conduct a taxonomic re-evaluation of many species, to describe new taxa, and to provide a framework for subsequent studies of crinoid community paleoecology.UUID:http://zoobank.org/e3e268a7-88e5-43cd-84ea-b40df45e8281

The Brechin Lagerstätte (Katian, Ordovician) from the Lake Simcoe region of Ontario, Canada contains a diverse array of echinoderms. Here, we describe seven disparid and two hybocrinid crinoids (subclass Pentacrinoidea, infraclass Inadunata), including a new disparid species belonging to the Anomalocrinidae (order Homocrinida). In total, the disparids include Anomalocrinus astrictus n. sp.; Cremacrinus guttenbergensis Kolata, 1975; C. inaequalis Billings, 1859; Daedalocrinus bellevillensis Billings, 1883; Eustenocrinus springeri Ulrich, 1925; Iocrinus trentonensis Walcott, 1883; and Isotomocrinus tenuis Billings, 1857b. The hybocrinids include Hybocrinus tumidus Billings, 1857a and Hybocystites problematicus Wetherby, 1880. Previously known from only the holotype, three additional specimens of E. springeri expand our understanding of this unusual crinoid. Nomenclatural acts include: (1) the recommended designation of D. kirki Ulrich, 1925 as a junior synonym of D. bellevillensis is followed; (2) Hybocrinus pristinus Billings, 1858 is designated as a junior synonym of H. tumidus, and previous decisions are followed to retain Hybocystites eldonensis (Parks, 1908) as a junior synonym of H. problematicus; (3) although probably assignable to Anomalocrinus Meek and Worthen, 1865, the aberrant crinoid Glaucocrinus falconeri Parks and Alcock, 1912, and its genus Glaucocrinus Parks and Alcock, 1912, are designated as nomena dubia; (4) Iocrinus similis (Billings, 1857) is also designated as a nomen dubium; and (5) Iocrinus subcrassus torontoensis Fritz, 1925 is designated a junior synonym of I. subcrassus Meek and Worthen, 1865.UUID: http://zoobank.org/90f8580b-ed7e-4405-97b2-73c9069de7f5

A bryozoan-dominated fauna that inhabited small caves underneath a carbonate hardground is here described from the Corryville Formation (Upper Ordovician, Katian) exposed near Washington, Mason County, Kentucky, USA. The dominant bryozoan,Stigmatella personata(a trepostome), is found both growing downwards from the cave ceilings and upwards on the exposed hardground surface above. Another trepostome,Monticulipora, is a minor component of the cave fauna. There are few discernible anatomical differences between the bryozoan colonies that grew upwards in presumably well-lit waters and those that grew downwards in the gloomy caves. The pendant, cave-dwellingS.personatain some cases appears to have longer zooecial tubes than its exposed equivalent. The colonies ofS.personataare rounded mounds with multiple layers formed by self-overgrowth. The overgrowths in both downward and upward growing forms are marked by thin layers of sediment infilling the upper zooecial chambers in the older portion of the colony. We suggest that biofilms developed on patches of the colony where the zooids had died. Sediment adhered to these surfaces and the colony then overgrew the patches, trapping sediment within the skeleton. The bryozoan zoaria and the carbonate hardground are extensively bored by the cylindrical ichnogenusTrypanitesthat occasionally contain cylindrical calcite-filled tubes similar to “ghosts” of organic materials. Bioclaustrations are present in some of the bryozoan skeletons. This cave fauna is one of few submarine examples known from the Paleozoic. It supports the hypothesis that early cave-dwelling organisms were little differentiated from their exposed counterparts.

The subfamily Hindellinae is an early group of athyride brachiopods, characterized by a simple jugum that connects the laterally directed spiralia, which are disjunct from the crura. Four genera (Hindella, Cryptothyrella, Koigia, and Hyattidina) are reexamined on the basis of their internal structures, such as the crura and their connection to the hinge, the jugum, and spiralia. The internal brachidium and shell of the Aeronian genus Cryptothyrella differ substantially from those of Hindella. Elkanathyris pallula n. gen. n. sp. is recognized as a posteriorly ribbed hindellide of Aeronian age. These genera are transferred from the Meristellinae to the subfamily Hindellinae (family Hindellidae). On Anticosti Island, Hindella is confined to the Hirnantian (latest Ordovician): it became extinct at the end Ordovician during the last of several mass extinction events that also extinguished the Laframboise reefs at the top of the Ellis Bay Formation. Post-extinction recovery of athyrides was pioneered by small-shelled Koigia, which are abundant in the basal Silurian Becscie Formation. Hyattidina, with a simple brachidium, is abundant in the Aeronian and Telychian of Anticosti, but absent earlier. True meristellines, as envisioned here, first appeared in the Aeronian Gun River Formation. The revised taxonomy and stratigraphic ranges of these earliest athyrides shed light on the nature of the Ordovician–Silurian mass extinction and recovery, and help refine the biostratigraphy of the O-S boundary interval.

Since 1986, samples with a total mass of more than 14,000 kg, mainly from three key sections in western Hunan, South China, have been processed for conodonts. Previous work mainly focused on biostratigraphy, but the taxonomy has been performed only on the faunas of the middle Cambrian. Described herein are conodonts of the upper Cambrian (Furongian Series) through lowermost Ordovician from Hunan, South China. Conodonts of the middle Cambrian are redescribed, based on material that has been recovered for more than three decades. The fauna consists of 82 species belonging to 36 genera. Newly established genera areLugnathusn. gen.,Miaognathusn. gen.,Millerodontusn. gen.,Tujiagnathusn. gen.,Wangcunellan. gen. andWangcunognathusn. gen. New species areCoelocerodontus hunanensisn. sp.,Furnishina wangcunensisn. sp.,Laiwugnathus hunanensisn. sp.,Laiwugnathus transitansn. sp.,Lugnathus hunanensisn. gen. n. sp.,Miaognathus multicostatusn. gen. n. sp.,Millerodontus intermediusn. gen. n. sp.,Prosagittodontus compressusn. sp.,Tujiagnathus gracilisn. gen. n. sp.,Wangcunella conicusn. gen. n. sp.,Wangcunognathus elegansn. gen. n. sp.,Westergaardodina dimorphan. sp.,Westergaardodina gigantean. sp., andWestergaardodina solan. sp. The taxonomy of some conodont genera is revised. In the light of histological investigation, genera are assigned to euconodonts, paraconodonts, or protoconodonts. The 13 conodont zones previously proposed in the middle Cambrian through lowermost Ordovician remain the same, but taxa within these conodont zones are documented more clearly because of the revised taxonomy proposed herein.

Conularina triangulata(Raymond, 1905), the genotype ofConularinaSinclair, 1942, is a rare, early Late Ordovician conulariid (Cnidaria, Scyphozoa; Van Iten et al., 2006) having three sides or faces instead of four (Sinclair, 1942, fig. 9; Van Iten, 1992, text-fig. 3E). Originally described from the Valcour Formation (early Sandbian; Dix et al., 2013) on Valcour Island, New York (Sinclair, 1942),C.triangulatahas since been found in laterally equivalent strata of the upper Laval Formation (‘Upper Chazy’; Sinclair, 1942) in Laval, Québec, Canada (Sinclair, 1942). From this same unit and area, Sinclair (1942) erected three new, four-sided species ofConularina(C.irrasa,C.raymondi, andC.undosa), and he erected a single four-sided species (C.narrawayi) from the Ottawa Formation (now the Sandbian–Katian Ottawa Group; Dix et al., 2013) at Tétreauville (now Gatineau), Québec. Subsequently, Jerre (1994) reported the occurrence of two species ofConularinain the Upper Ordovician of Sweden. Jerre (1994) also proposed thatEoconularia?forensisSinclair, 1946 from the Upper Ordovician Citadelle Formation (‘Quebec City’ Formation; Sinclair, 1946) in Québec City, Québec (Promontoire de Québec thrust sheet, Appalachian Humber Zone, Allochtonous Domain; Castonguay et al., 2002) is a species ofConularina.

Two new kirkocystid mitrate stylophorans (Echinodermata, Homalozoa) and a new possible solute (Echinodermata, Homalozoa) are described from the Early Ordovician of the western United States. The mitrates are among the earliest members of their clade to appear near the beginning of the Ordovician Radiation.Anatifopsis ninemilensisnew species comes from the Ninemile Shale in central Nevada and the McKelligon Canyon Formation in west Texas.Anatifopsis fillmorensisnew species comes from the middle Fillmore Formation in western Utah and a Ninemile Shale equivalent limestone bed in southern Nevada. The possible soluteDrepanocystis dubiusnew genus new species from the lower Wah Wah Limestone in western Utah, shows unusual morphology with an elongate theca and a long arm shaped like a sickle.

The genusNeseuretusHicks, 1873 is the most abundant trilobite of the Ordovician siltite succession of the Andouillé and Traveusot Formations in the French Armorican massif. The systematics of some species ofNeseuretusis still unclear. Armorican and Iberian domains formed part of a distinctive paleobiogeographical province in the Ordovician and, while fiveNeseuretusspecies were defined in Iberia that follow each other through time, from the Middle to the Upper Ordovician, only oneNeseuretusspecies,N. tristani, has been identified in the Armorican massif so far. The discovery of new fossil deposits in the Ménez-Belair syncline has led to the identification and re-description of threeNeseuretustaxa:Neseuretus avusHamman, 1977 from the early-middle Darriwilian,Neseuretus tristani(Brongniart in Desmarest, 1817) from the late–middle Darriwilian to late Darriwilian andNeseuretus tardus(Hammann, 1983) from the Darriwilian–Sandbian boundary and early Sandbian. Morphological characters of the cephalon and pygidium were determined that can definitively distinguish the three identified taxa. These results stem from both traditional and geometric (outline and landmark-based) morphometric analyses. The three taxa follow each other through time and constitute a morphological sequence that contributes to improving the stratigraphy of the Middle and Upper Ordovician.

The dramatic late Early Ordovician radiation of cephalopods on tropical paleocontinents is illustrated by the diverse fauna (21 genera, 30 species) of the Fort Cassin Formation (Floian and lower Blackhillsian Stage) in northeast Laurentia. Cephalopods occur through the thin (ca. 30–65 m) depositional sequence of the Fort Cassin but are most common and diverse in mollusk-rich, trilobite-poor parts of the formation that characterize the thrombolite-bearing intervals in the shoaling part of the highstand systems tract. This lithofacies-biofacies linkage persists from the Tribes Hill and Rochdale Formations (lower and lower upper Tremadocian, and upper Skullrockian and Stairsian Stages, respectively), and suggests that the Early Ordovician radiations of cephalopods took place in shallow-marine, thrombolite reef facies of tropical carbonate platforms. These habitats differed strongly from the near-shore, peritidal habitats of the older Cambrian evolutionary radiation. Genus-level diversity and absolute abundance changed little through the Skullrockian-Blackhillsian, but morphologic diversity and body size increased dramatically by the late Early Ordovician. The morphological diversification suggests cephalopods diversified into a wider variety of macropredators and more complex late Early Ordovician ecosystems.Anrangeroceras whitehallensen. gen. and n. sp. is proposed. The following are emended: the Protocycloceratidae,CentrotarphycerasandC. seelyi, ProtocyclocerasandP. lamarcki,andRudolfoceras cornuoryx.The following are indeterminate and abandoned:Baltoceras? pusillumRuedemann, 1906;Comeroceras annuliferumFlower, 1941;Cyptendoceras whitfieldiUlrich et al., 1944;Endoceras? champlainenseRuedemann, 1906;Wolungoceras valcourenseFlower, 1964.BeekmanocerasUlrich and Foerste, 1936 is a gastropod.

A large and abundant columnar stromatoporoid, Quasiaulacera n. gen., from the Ellis Bay Formation, up to 3 m long and 40 cm in diameter, marks the Hirnantian (latest Ordovician) of Anticosti Island. Two species are present: Quasiaulacera stellata n. sp. from the basal Ellis Bay Formation (basal Prinsta Member, lower Hirnantian) along the northeastern coast of the island, and the type species Q. occidua n. sp. from the upper Ellis Bay Formation (Lousy Cove Member, upper Hirnantian) in the western carbonate facies of the island. Quasiaulacera is rare or absent in the reefal Laframboise Member (uppermost Hirnantian) of the formation. The new genus differs from Aulacera in the underlying Vaureal Formation (upper Katian) in having a large central axial zone marked by a single stack of large, convex-up cyst-plates, that is surrounded by a middle layer of small, concentric microcyst-plates, in places denticulate, and an outer layer composed of concentric laminae with dense pillars, in which microcyst-plates are either absent or rare. The outer two layers are defined by longitudinal fluting; there are no branching forms. Both species demonstrate a ball-like holdfast system, some with diameters of 30 to 70 cm, microbially cemented into the substrate. Quasiaulacera “gigantism” in the paleotropical Anticosti Basin evolved at a time of global cooling associated with the Hirnantian glaciation in south polar Gondwana, but terminated in mass extinction of the aulaceratids at the O/S boundary in Laurentia. This supports other evidence that the Hirnantian featured not only generic loss, but also innovation and migration in tropical latitudes.

10 páginas., A comprehensive treatment of Ordovician crinoids from southwestern Europe is presented, including taxa based on articulated crowns and stems. This summary incorporates new material, new localities, and a revision of some southwestern Europe occurrences. The first record of an Ordovician crinoid from Portugal, Delgadocrinus oportovinum n. gen. and sp., is reported, and this is the oldest known crinoid from the Iberian Peninsula (Arenigian/Oretanian boundary, early Darriwilian). Geographic and temporal ranges of several crinoids are revised from peri-Gondwanan areas in southwestern Europe and northern Africa or modified with new Iberian material. The Spanish range of Heviacrinus melendezi Gil Cid et al., 1996 is extended down into the lower upper Oretanian, and Merocrinus millanae Ausich et al., 2002 is restricted to the upper lower Dobrotivian. The stratigraphic position of Ortsaecrinus cocae Gil Cid et al., 1999b is restricted to the early middle Berounian, and the range of Visocrinus castelli Ausich et al., 2002 is restricted to the late middle Berounian (see Fig. 2). New topotype material of Morenacrinus silvani Ausich et al., 2002 is reported that furthers understanding of the occurrence this taxon, which was previously only positively known from the holotype.

Black shales of the Coroico Formation are part of a thick succession of Lower and Middle Ordovician strata that were deposited in the Cordillera Oriental foreland basin along the margin of West Gondwana. The basin was inhabited primarily by a cool-water, Atlantic-type graptolite fauna. Newly discovered material from rocks that crop out near the town of Consata in NW Bolivia include unexpected warm-water or Pacific-type elements such as Parisograptus caduceus and Pseudotrigonograptus within an assemblage dominated by abundant pendent Didymograptus specimens, Cryptograptus schaeferi, and diplograptaceans such as Oelandograptus oelandicus and Hustedograptus bulmani n. sp. Parisograptus caduceus has generally been considered to be restricted to oceanic depths below those of the epipalagic realm that occupied continental shelves, whereas the remainder of the assemblage is more characteristic of relatively shallow water, epicratonic sites. We interpret this mixed assemblage to be the Atlantic Province, West Gondwanan equivalent of the off-shore isograptid biofacies that is much more widely known from low latitude sites around the globe. These results suggest that in this region of West Gondwana, the properties of local water masses (productivity and physical features such as temperature, salinity, or oxygenation) strongly influenced graptolite species distribution and led to biofacies differentiation among coeval assemblages. It also suggests that some isograptids inhabited the epipelagic biotope in mid to high latitude regions. The new species Hustedograptus bulmani is described herein.

The polyplacophoran Matthevia Walcott, 1885 has been reported previously only from Cambrian rocks. Recovery of specimens of two different species of Matthevia from the top of the cherty lower Gasconade Dolomite in Missouri extends the known range of the genus into the Ordovician. The presence of the Lower Ordovician trilobite Praepatokephalus Lochman, 1964 in one collection provides the biostratigraphic evidence that the new specimens of Matthevia are Ordovician in age. Matthevia erecta n. sp. is described. An emended diagnosis for the trilobite Praepatokephalus is provided; two species of the genus are briefly described but are left in open nomenclature as P . sp. A and P . sp. B. Collections were made from 10 localities. The 10 specimens of Matthevia described here are from localities 4 and 6 in the upper part of the cherty lower Gasconade Dolomite of eastern Missouri, south of St. Louis (Figs. 1, 2). Locality 4 is at Spring Branch in Meramec State Park. Locality 6, which is just west of the settlement of Old Mines, Missouri, is owned by Guy and Doris Darrough. The species of Matthevia described here are the first undoubted representatives of the genus reported from rocks of Ordovician age. Figure 1 —Stylized stratigraphic section of the Cambrian–Ordovician boundary beds in eastern Missouri. The disconformity between the Eminence and Gasconade marks the traditional Cambrian–Ordovician boundary. The work herein and the definition of the boundary by Cooper et al. (2001) indicate that the boundary in eastern Missouri is at the top of the Gunter Sandstone Figure 2 —Generalized locality map of study area Stinchcomb and Darrough (1995, p. 54) noted the occurrence of Matthevia in the Gasconade Dolomite; however, they did not describe or illustrate any specimens from this formation. The single specimen they figured is from some unspecified level …

Well-preserved earliest Ordovician (early to middle Tremadocian) radiolarian faunas were recovered from carbonate rocks of the Cow Head Group of the Great Northern Peninsula of the island of Newfoundland, Canada. The earliest Ordovician faunal assemblages are from Green Point, Martin Point, Broom Point North and South, and St. Paul's Inlet in Gros Morne National Park. Latest Cambrian faunas were also recovered from Green Point and St. Paul's Inlet, but are extremely low in both abundance and diversity. The radiolarian faunas include five families, 10 genera, and 24 species. Of these, one family Aspiculumidae, one genus, and 19 species are new. The new family and new genus are Aspiculumidae and Aspiculum, respectively. The new species are Pararcheoentactinia? cowheadensis, Aspiculum eccentricum, Aspiculum? angulatum, Parechidnina delicata, P. variospina, Curvechidnina multiramosa, Echidnina conexa, E. laxa, E. semiconexa, E. severedeformis, Echidnina? immanis, Palaeospiculum curvum, P. multifurcat...

Previous reports of Cambrian bryozoans have proved not to be bryozoans. No pre-Ordovician bryozoans have been recognized. The oldest unequivocal bryozoans known from North America, Britain, and Russia are evidently of early Arenigian age. New bryozoans recently collected from the Fenxiang Formation in the Daping and Guanzhuangping sections, situated in the area east of the Yangtze Gorges, are described here, including one new genus,Orbiramus, and six new species,Nekhorosheviella nodulifera, N. semisphaerica, Orbiramus normalis, O. ovalis, O. minus, andProphyllodictya prisca.These are assigned to the Trepostomida, apart from the last species which belongs to the Cryptostomida. The new bryozoans are from the conodontPaltodus deltifer deltiferZone of the late Tremadocian age, the first three species possibly being present in theP. deltifer pristinusSubzone at the base. Therefore, they are the oldest bryozoans known from anywhere in the world. Extensive reefs resulting from a major regression in the late Tremadocian were dominated by bryozoans in the upper Fenxiang Formation. The bryozoans lived in a shoal environment and accumulated essentially in situ, showing no signs of significant transportation.

Seven genera and eight species of lingulate brachiopods are described from the Cambrian-Ordovician boundary beds (Cambrooistodus minutus Conodont Subzone to Rossodus manitouensis Conodont Zone) at the Lawson Cove and Lava Dam North sections, Ibex area, Utah, USA. The fauna includes one new linguloid genus, Wahwahlingula, and four new species, Lingulella? incurvata, Zhanatella utahensis, Conotreta millardensis, and Quadrisonia? lavadamensis. Lingulate brachiopods from this interval are very poorly known from Laurentia, but the recorded fauna is very similar to that described from coeval beds at Malyi Karatau, Kazakhstan, and both areas contain Eurytreta cf. bisecta (Matthew, 1901); E. sublata Popov, 1988; Zhanatella Koneva, 1986; Schizambon Walcott, 1889; and Wahwahlingula. Eurytreta cf. bisecta is also known from the Lower Ordovician of Avalonian Canada, Britain, and Scandinavia.

Linguliform brachiopods were recovered from the Upper Cambrian Downes Point Member (lower Sunwaptan) and from the Middle Ordovician Factory Cove Member (Arenig) of the Shallow Bay Formation, Cow Head Group, of western Newfoundland. These rocks are a series of Middle Cambrian to Middle Ordovician conglomerates, lime mudstones, and shales that formed a sediment apron at the base of the lower Paleozoic continental slope of Laurentia. The linguliform brachiopod fauna consists of sixteen species assigned to twelve genera. Three new species are described: Picnotreta lophocracenta, Neotreta humberensis, and Siphonotretella parvaducta.

Gnamptorhynchos, a rhynchonellid-like orthid brachiopod, evolved from Platystrophia in Maysvillian (early Ashgill) time, and survived both the end-Richmondian and end-Hirnantian episodes of the latest Ordovician mass extinction. The name of the type species of Gnamptorhynchos, G. inversum Jin, 1989, is rejected and replaced by Gnamptorhynchos globatum (Twenhofel, 1928), which is a senior synonym. Gnamptorhynchos manitobensis new species is described here from the Selkirk Member (Maysvillian) of the Red River Formation, southern Manitoba. The new species is characterized by a transversely extended, strongly biconvex to globular shell with prominent umbones, relatively numerous costae and a notothyrial cavity supported dorsally by a short median ridge. It constituted part of a Late Ordovician epicontinental fauna that once spread widely in shallow, equatorial seas of North America. The new species is a morphological intermediate between Platystrophia and Gnamptorhynchos, with Platystrophia-like int...

Abundant and morphologically fairly diverse siliceous sponge spicules of Darriwilian (Middle Ordovician) age were collected from the Table Cove Formation of Port au Port Peninsula, western Newfoundland. Without co-occurrence of appropriate sponge body fossils, it is difficult to refer these disarticulated sponge spicules to existing or to new taxa. However, representatives of demosponges and hexactinellids are recognized. While marked differences are noted between older and younger lithistid dendroclones, for example, spicule form in these Middle Ordovician specimens is similar overall to previously known assemblages of various ages, demonstrating the morphologically conservative nature of the spicular skeleton.

Seven new monoplacophoran genera and species are described and figured from Cambrian and Lower Ordovician strata of the Ozark Uplift of Missouri; Biloboconus frizelli, Ulrichoconus bonneterrense, Potosiplina delorensis, Gayneoconus echolsi, Irondalia irondalensis, Titanoplina meramecensis, and Wildernessia inexpectans. A new species of Kirengella, K. oregonensis, is described, and Hypseloconus compressus (Ulrich and Bridge, 1930, and H. expansus Stinchcomb, 1986, are assigned to the genus Kirengella. The morphology of Kirengella is compared to highly arched forms of the plated mollusk genus Preacanthochiton and is found to converge with them. Association with stromatolite reefs of both Kirengella and plated mollusks is noted.

The Little East Lake Formation represents a spectrum of Late Ordovician (Ashgill) nearshore environments. These physical environments are characterized by a variety of quartz- and feldspar-rich sandstone and slate. Depositional environments include neritic nearshore, beach, tidal flat, and alluvial(?). The beach and neritic nearshore environments contain a variety of fossil invertebrates. The majority of the brachiopod fauna is confined to two taxa:Eodinobolus rotundusHarper, 1984, andDalmanella testudinaria ripaeMitchell, 1978(inCocks, 1978). Some of the specimens have been broken and abraded suggesting transport within the beach swash zone. Gastropods includeLophospiracf.L. milleri(Hall),Lophospira(?),Trochonemellacf.T. notabilis(Ulrich and Scofield), andDaidia cerithioides(Salter). Tidal-flat environment contains the trace fossilsPalaeophycusandPlanolites.The Late Ordovician (Caradoc and Ashgill) sedimentary basins developed subsequent to the collisional Taconian orogeny, wherein an arc accreted to the eastern Laurentian margin. Prior paleomagnetic reconstructions place the southeastern continental margin of Laurentia at approximately 25° south latitude during the Late Ordovician. Using these reconstructions, the siliciclastic Ashgill rocks discussed here would have been deposited in an elongated, northeast-trending basin on the southeastern Laurentian margin. The fauna developed along this margin, but in contrast to possibly adjacent Irish and Scottish assemblages, was located in much shallower water.

Brachiopods assigned to eight genera and 15 species have been recovered from Upper Cambrian (Franconian and Trempealeauan Stages) and lowest Ordovician strata in the Arbuckle and Wichita Mountains of Oklahoma. Species ofOcnerorthisandEoorthisoccur in the Reagan Sandstone and Honey Creek Limestone of the Timbered Hills Group. Species ofBillingsellaappear in the Honey Creek and range upward into the overlying Fort Sill and Signal Mountain Limestones of the Arbuckle Group. Species ofCymbithyris, Finkelnburgia, Nanorthis, andApheoorthissucceed each other upsection in the Signal Mountain Limestone. Five brachiopod zones and one subzone have been established that can be used to correlate the measured sections in the Arbuckle and Wichita Mountains, and to correlate with varying degrees of confidence from Oklahoma to similar brachiopod occurrences in other areas in the United States.

In 1892 the Swedish paleontologist Johan Christian Moberg described and illustrated what he interpreted as a fossil insect (Hemiptera) from beds of early Ordovician age in the southernmost limestone quarry at Killeröd, Smedstorp Parish in Skåne [Scania], southern Sweden. In a later paper in the same year (Moberg, 1892b), he also made a further passing reference to the presence of the same fossil when describing the accompanying graptolite fauna from Killeröd. One of his main reasons for recording this find was his conclusion (Moberg, 1892a, p. 122) that “it is evidently of great interest with full certainty to be able to prove the presence of airbreathing (terrestrial) animals as far back in time as that during which the oldest strata of the lower Silurian [i.e., Ordovician] were formed” [translation from Swedish].

New collections, as well as original type material, of Lower and Middle Ordovician sponges from the Mingan Island Archipelago are described and figured from the Mingan and Romaine Formations. Archaeoscyphia minganensis (Billings, 1859), Hudsonospongia minganensis Raymond and Okulitch, 1940, H. irregularis Raymond and Okulitch, 1940, H. duplicata Raymond and Okulitch, 1940, Zittelella varians (Billings, 1861a), and Eospongia roemeri Billings, 1861, are redescribed from original type specimens and new collections. The species Archaeoscyphia pulchra (Bassler, 1927), Rhopalocoelia clarkii Raymond and Okulitch, 1940, Psarodictyum magnificum Raymond and Okulitch, 1940, and Lissocoelia ramosa Bassler, 1927 are reported and described from the Mingan Islands for the first time. To these sponges are added the new species Anthaspidella amplia, Archaeoscyphia undulata, Hudsonospongia nodosa, and Zittelella grossa, which are described from type specimens from the Mingan Formation.The assemblage from 12 localities from the Mingan Formation, and one from the Romaine Formation, represents one of the most diverse demosponge faunas from eastern North America. Sponges in most of the localities accumulated as transported debris or lag gravels, but locally, some grew in small reefoidal mounds and also accumulated as adjacent debris.

Review of collections in Prague and at Harvard University, supplemented by additional field observations, has allowed taxonomic updating and revision of Barrandian trinucleid trilobites. Genera identified areBergamia, Declivolithus, Nankinolithus, Tretaspis, Marrolithus, Deanaspis, andOnnia. One earlier described species is assigned to the new genusMarekolithus.Although partly isolated from the rest of north Gondwana during the Ordovician, the Prague Basin shares faunas with Sardinia and Morocco, as all show the transition fromDeanaspistoOnnia. Spain, Britain, and the Baltic also share some species with Bohemia, particularly in the high Caradoc and Ashgill (Bohdalec and Králův Dvůr Formations).

Trilobites from the Missisquoia Zone and the Symphysurina brevispicata Subzone of the Symphysurina Zone (Ibexian Series, lowest Ordovician) were collected from measured sections in the uppermost Deadwood Formation in the Black Hills of South Dakota and Bear Lodge Mountains in northeasternmost Wyoming. These collections were made by Christina Lochman-Balk and her students, and turned over to the author to complete the project. They are compared with previous reported occurrences of this fauna from this area. No trilobites from the underlying Sunwaptan Stage (Upper Cambrian) occur with the lowest Ordovician trilobites, suggesting that the sharp faunal extinction at the base of the Ordovician (North American sense = Eurekia apopsis Zone, Ibexian Series) occurred in the Deadwood Formation as it did over all of the North American continent. The Black Hills is a domal uplift cored by Precambrian granites and quartzitic and schistose metamorphic rocks that was formed during the Laramide orogeny (Stitt, 1998). The Deadwood crops out as an oval belt of siltstones, sandstones, shales, and limestones unconformably overlying the Precambrian rocks. Specimens used in this study were collected from a series of measured sections located in the northernmost outcrop belt of the Deadwood. Hu (1973) identified lowest Ordovician trilobites from one section (Bridal Veil Falls) in the northern Black Hills and from three sections (Reuter Canyon, Bearlodge Ranch, and Sheep Mountain) in the nearby Bear Lodge Mountains. He also described one new genus and four new species. His composite faunal list, and subsequent taxonomic reassignments in brackets, include the following trilobites: Euloma cordilleri [= Highgatella cordilleri Winston and Nicholls, 1967], Euptychaspis trematocus, Highgatella facila [= Apoplanias rejectus Ludvigsen, 1982], Hystricurus sp., Missisquoia graphica [= Missisquoia typicalis Westrop, 1986], Missisquoia cyclochila [= Missisquoia typicalis Ludvigsen, 1982], cf. Missisquoia typicalis, Olenaspella elongata, Symphysurina brevispicata, and the brachiopod …

Cocks and Rong (1989) subdivided the species of the Ordovician brachiopod genusBimuriainto two groups, those with a simple, or not undercut, cardinal process and those with an undercut cardinal process. They placed the second group in a new genus,Cooperea, and groupedCoopereawithCraspedeliain the new subfamily Craspedeliinae of the family Sowerbyellidae. However, the cardinal process ofBimuriaranges from not undercut to undercut within at least two species.Coopereais therefore placed in synonymy withBimuria, andCraspedeliais returned to the Bimuriidae.Cocks and Rong (1989) inferred that, with rare exceptions, the cardinal process of the Plectambonitacea evolved from simple to trifid to undercut. The evidence fromBimuriaindicates, however, that the undercut process developed more than once and, inBimuria, directly from the simple type.As an adjunct to the above discussion three new species are described:Bimuria gilbertella, Craspedelia intonsa, andCraspedeliasp. 1.Craspedeliais a rarely reported genus documented here for the first time in western North America (northern California). Additional evidence is introduced that the ratio Lmusbv/Lebv decreased from middle to late Ordovician species ofBimuria.

New species of Aphelognathus, Belodina, Taoqupognathus, and Yaoxianognathus have been identified in the Late Ordovician Cliefden Caves Limestone Group in central-western New South Wales, Australia. Of the Aphelognathus species, Aphelognathus percivali n. sp. and A. webbyi n. sp. occur in the basal Gleesons Limestone Member and A. packhami n. sp. and A. stevensi n. sp. occur 30 m higher in the Wyoming Limestone Member. It seems likely from the similarity of several of the elements that A. packhami is closely related to A. percivali, and A. stevensi to A. webbyi. Yaoxianognathus wrighti n. sp. occurs in the Gleesons Limestone Member but not in the Wyoming Limestone Member. Belodina confluens, Belodina hillae n. sp., Belodina n. sp., Panderodus gracilis, Taoqupognathus philipi n. sp., and Phragmodus? tunguskaensis occur at both horizons. The conodonts suggest a middle to late Caradocian (mid-Shermanian to mid-Edenian) age for the lowest part of the Cliefden Caves Limestone. The occurrence in southeastern Australia of the forms Taoqupognathus, Yaoxianognathus, and Phragmodus? tunguskaensis suggest affinities to coeval faunas in China and eastern Siberia. The four new species of Aphelognathus are distinct from known species in the Late Ordovician of North America and Europe but they may help characterize a paleobiogeographic region that includes eastern Australia and southeast Asia.

Description of two new specimens of Macroscenella superba (Billings) provides additional data on this rare, poorly known Paleozoic genus. Macroscenella was considered first to be a gastropod, then a monoplacophoran, and finally a coelenterate. Chondrophorine affinities for this form cannot be totally ruled out, but the new specimens increase the probability that it is a mollusk. If so, Macroscenella is more likely a patellacean gastropod than a member of any other group of the Mollusca, though evidence for placement within the Mollusca is equivocal; the interior of the specimens is not exposed and musculature is unknown. If the integument was a shell, it was thin.