Eoastropecten sechuanensis, Gale, 2020

Gale, Andrew S., 2020, A new comb-star (Asteroidea, Astropectinidae) from the Upper Triassic (Carnian) of China, Zootaxa 4861 (1), pp. 139-144 : 142-143

Eoastropecten sechuanensis sp. nov.

Figure 2 A–H

Diagnosis. As for genus.

Type material. The superomarginal figured ( Fig. 2A, E ) is the holotype (Muschelkalkmuseum, Ingelfingen, Germany, MHI 2183/1), the other figured ossicles are paratypes (MHI 2183/2-6) .

Additional material. 25 marginal ossicles (MHI).

Type locality. Jiancougou , Sechuan Province, China .

Type stratum. Maantang Formation (sample C30 of Forel et al. 2019), Carnian (Upper Triassic) .

Etymology. Named after the Sechuan Province.

Description. External surfaces of marginals with well-defined, depressed rim of even width. Sculpture of raised central region consisting of fine, evenly sized rugosities, partly conjoined by narrow, radiating strips of stereom ( Fig. 2G ). Rugosities non-aligned and evenly spaced on superomarginals, but arranged into irregular, oblique rows on the inferomarginals ( Fig. 2C ). Interradial superomarginals short, median ossicles wedging slightly towards lateral border ( Fig. 2G ); distal superomarginals broad, rectangular ( Fig. 2A, F, H ). In proximal/distal view, external face evenly curved. Inferomarginals ( Fig. 2C, D ) broad, short, with low profile, strongly convex at abactinolateral margin. Proximal actinal surface embayed for articulation of actinal ossicles. The rectangular abactinal outline of the marginals can be taken as evidence that the interradial arcs were evenly concave.

Figures

FIGURE 2. A–H, Eoastropecten sechuanensis gen. et sp. nov., marginal ossicles. A, E, holotype superomarginal in abactinal (A) and proximal (E) view (MHI2183/1). B, paratype superomarginal in proximal/distal view (MHI2183/6). C, D, paratype inferomarginal in actinal (C) and distal (D) views (MHI2183/3). B, paratype superomarginal in proximal/distal views (MHI2183/2). F–H, paratype superomarginals in abactinal view (MHI2183/4, /5). I, unidentified astropectind superomarginal in abactinal view (NHMUK EE 17700). J, astropectinid superomarginal in abactinal view (NHMUK PI EE 17701). K, L, marginals of living astropectinid Craspidaster hesperus (Müller & Troschel, 1840), J, superomarginal in abactinal view. K, L, supero-inferomarginal pair.A–H, Maantang Formation (Carnian, Triassic), sample C30, Jiancougou, Sechuan Province, China. I, Lower Oxfordian, Andelot-Morval, Départment du Jura, France. J–L, Recent, Hong Kong.