Search

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.

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."]}