Sinocrinus websteri, Ausich & Križnar & Paszcza & Hoşgör & Płachno & Salamon, 2024

Ausich, William I., Križnar, Matija, Paszcza, Karolina, Hoşgör, İzzet, Płachno, Bartosz J. & Salamon, Mariusz A., 2024, Early Permian crinoids from Laurasia and their paleogeographic implications, Acta Palaeontologica Polonica 69 (3), pp. 447-466 : 460-461

Sinocrinus websteri sp. nov.

Fig. 4F .

ZooBank LSID: urn:lsid:zoobank.org:act:44E00651-5794-41FF-9452-899180B7D977 .

Etymology: In honour of Gary D. Webster (1934–2021), whose work greatly advanced our understanding of Permian crinoids around the world.

Holotype: PMSLJ Ba 373; moderately preserved aboral cup.

Type locality: Near Dovje, Slovenia.

Type horizon: Trogkofel Group, Permian, Cisuralian, middle to upper Artinskian.

Diagnosis. —Low bowl-shaped aboral cup, aboral cup plate sculpturing unknown, aboral cup circular in basal view, basal concavity present, proximal column cicatrix>60% of infrabasal circlet diameter, infrabasal circlet not confined to basal concavity, height of all infrabasal plates equal, basal plates gently convex, basal plates wider than high, arms unknown, moderately developed crenulae in the proximal column cicatrix, proximal columnal circular.

Measurements. —ACH, 19.2; ACW~34.0.

Description. —Aboral cup low bowl shape, height width ratio ~0.5, circular in basal view, basal concavity present; plates convex, sculpturing not certain due to weathering, impressed sutures. Infrabasal circlet not visible in lateral view, not confined to basal concavity column cicatrix ~77% of the width of the infrabasal circlet; infrabasal plates presumably partially fused into one plate with very faint sutures, height of all infrabasal plates equal. Basal plates five, pentagonal, gently convex, smaller than radial plates, ~1.7 times wider than high. Radial plates presumably five, pentagonal, ~1.6 times wider than high. Radial facets plenary, horizontally oriented, articular ridge probably across full width of facet, but other details of radial facet not known. No posterior interray plates in CD interray. Oral surface, anal sac, and arms unknown. Moderately developed crenulae in proximal columnal cicatrix, proximal column circular, other aspects of column unknown.

Remarks. —Other Permian species of Sinocrinus include S. granulatus , S. lichengensis , S. obliquus , and S. sheareri (see Sheffield 2015; Mao et al. 2018). These species are differentiated on the shape of the aboral cup, aboral cup plate sculpturing, aboral cup outline in basal view, width of the basal concavity on the infrabasal circlet, relative sizes of infrabasal plates, nodose projection on first primibrachials, column impression on infrabasal circlet, and shape of the proximal columnal. Sinocrinus granulatus has a low cone-shaped aboral cup, fine granulose aboral cup plate sculpturing, circular calyx outline in basal view, basal concavity occupies <60% of infrabasal circlet diameter, all infrabasal plates are of equal height, nodose projections on distal side of first primibrachials, pronounced impression of proximal column crenulae on infrabasal circlet, and proximal column circular; S. lichengensis has a low cone-shaped aboral cup, faintly granulose aboral cup plate sculpturing, slightly pentalobate calyx outline in basal view, basal concavity occupies <60% of infrabasal circlet diameter, individual infrabasal plates of varying heights, first primibrachials unknown, pronounced impression of proximal column crenulae on infrabasal circlet, and proximal column pentalobate; S. obliquus has a low conical aboral cup shape, coarse irregular granulose aboral cup plate sculpturing, circular calyx outline in basal view, basal concavity occupies <60% of infrabasal circlet diameter, individual infrabasal plates of varying heights, first primibrachials unknown, pronounced impression of proximal column crenulae on infrabasal circlet, and proximal column circular; and S. sheareri has a very low bowl aboral cup shape, smooth aboral cup plate sculpturing, circular calyx outline in basal view, basal concavity occupies 100% of infrabasal circlet diameter, all infrabasal plates are of equal height, first primibrachials unknown, moderately developed impression of proximal column crenulae on infrabasal circlet, and proximal column circular. In contrast, S. websteri sp. nov. has a low bowl-shaped aboral cup, unknown aboral cup plate sculpturing, circular calyx outline in basal view, basal concavity occupies>60% of infrabasal circlet diameter, all infrabasal plates are of equal height, nodose projections on distal side of first primibrachials, moderately developed impression of proximal column crenulae on infrabasal circlet, and proximal column circular.

Pennsylvanian Sinocrinus were cosmopolitan with a distribution including China, Spain, and USA. However, Permian occurrences of Sinocrinus include now Sinocrinus granulatus and S. obliquus in the Artinskian of Timor, S. lichengensis in the Sakmarian of Crete, Greece, S. shearieri from the Asselian of the North China Block, and S. websteri sp. nov. in the middle to upper Artinskian of Slovenia.

Stratigraphic and geographic range. —Trogkofel Group, Permian, Cisuralian, middle to upper Artinskian, near Dovje, Slovenia.

Figures

Fig. 4. Crinoids from Dovje, Slovenia, lower Permian, Cisuralian, Artinskian. A. Crinoidea indet. GMJ:PAL-0000373a, infrabasal circlet in basal view. B. Parastachyocrinus sloveniaensis sp. nov., GMJ:PAL-0000014c, aboral cup in basal view. C. Protencrinid Protencrinus baliensis Webster, 2012b, GMJ:PAL-0000002, aboral cup in basal view. D. Crinoidea indet. GMJ:PAL-0000373b, infrabasal circlet in basal view. E. Euryocrinid Dieuryocrinus? sp. GMJ:PAL-0000368, an incomplete calyx in basal view. F. Erisocrinid Sinocrinus websteri sp. nov., holotype, PMSLJ Ba373, aboral cup in basal (F1) and lateral (F2) views. G. Eucladid indet.A, GMJ:PAL-0000014b, aboral cup in basal (G1) and lateral (G2) views. Scale bars 10 mm.