Punkaster ruegenensis, Gale & Jagt, 2021

Gale, Andy S. & Jagt, John W. M., 2021, The fossil record of the family Benthopectinidae (Echinodermata, Asteroidea), a reappraisal, European Journal of Taxonomy 755, pp. 149-190 : 172-174

Punkaster ruegenensis gen. et sp. nov.

urn:lsid:zoobank.org:act:9762A572-434A-4D16-86F8-644D05201BC4

Fig. 12A–I, L–M

Diagnosis

Punkaster gen. nov. in which the proximal supero- and inferomarginals form fused pairs; distally, they are separate. Large marginal spine bases absent.

Etymology

Named after the island of Rügen (northeast Germany) in the Baltic Sea.

Material studied

The interradial marginal pair ( Fig. 12A ) is the holotype ( SNSB-BGSP 2020 XLV 31 ); the other eight ossicles illustrated here are paratypes ( SNSB-BGSP 2020 XLV 32–39 ), all from the upper lower Maastrichtian Chalk of Rügen, northeast Germany. Additional material includes over 30 marginal ossicles and other ossicles from the same locality (lot SNSB-BGSP 2020 XLV 32 ).

Description

Proximal marginals fused, bilobed; actinal part formed by a low, elongated, concave inferomarginal, abactinal part a subrectangular flange, formed by superomarginal ( Fig. 12A–E, H–I ). Infero- and superomarginals separated by a notch of variable size. Proximal/distal profile L-shaped, articulation facets for adjacent marginal plates oval ( Fig. 12D ). External sculpture of coarse reticulate stereom network, with rugosities, and small cylindrical projections which carried spines. Distal inferomarginals ( Fig. 12F–G ) rectangular, elongated, with similar sculpture to proximal plates. Presumed adambulacral ( Fig. 12L–M ) boot-shaped, with deep podial notch and narrow distal portion. Large fs bases present, central actinal face slightly inset, coarsely reticulate, rugose.

Remarks

The marginal ossicles are most unusual in that supero- and inferomarginal pairs are fused, perhaps uniquely amongst asteroids. The overall shape and sculpture of the ossicles suggest affinity with the type species, Punkaster spinifera gen. et sp. nov. (see above), but the present form differs in the fused proximal marginals and in the absence of large spine bases.

Figures

Fig. 7 (next page). A–J. Jurapecten infrajurensis sp. nov., various ossicle types (paratypes). A, H. Ambulacrals, in lateral and actinal aspects, respectively (SNSB-BGSP2020XLV 21,SNSB- BGSP2020XLV 28). B, E–F. Adambulacrals, in actinal and abactinal views (SNSB-BGSP2020XLV 22, SNSB-BGSP2020XLV 25–26). C, G, J. Superomarginals, in lateral views (SNSB-BGSP2020XLV 23, SNSB-BGSP2020XLV 27, SNSB-BGSP2020XLV 30). D, I. Inferomarginals, in lateral views (SNSB-BGSP2020XLV 24, SNSB-BGSP2020XLV 29). — K–Y. Jurapecten hessi Gale, 2011. K, P, U. Adambulacral ossicles. K. Abactinal view (NHMUK PI EE 17996). P. NHMUK EE 13598 (the original of Gale 2011a: pl. 19 fig. 11). U. NHMUK EE 13599, the original of Gale (2011a: pl. 20 fig. 12). L. Circumoral ossicle (NHMUK EE 13605, the original of Gale 2011a: pl. 20 fig. 13). M–N. Ambulacral ossicles, in actinal and abactinal views, respectively (NHMUK EE 13595–13596, the originals of Gale 2011a: pl. 19 figs 8–9). O. Ambulacral, in proximal/distal view (NHMUK 13597). Q–S. Superomarginal ossicles (NHMUK EE 13601–13602; the originals of Gale 2011a: pl. 20 figs 6–7). T, V–W. Inferomarginals (NHMUK EE 13600, EE 13603–13604, EE 13608, the originals of Gale 2011a: pl. 20 figs 5, 8, 16). X–Y. Oral ossicles (NHMUK EE 13606– 13607, the originals of Gale 2011a: pl. 20 figs 10, 14). Provenance: A–J. Upper Toarcian–lower Aalenian (possibly aalensis ammonite Zone), Quedlinburg (Landkreis Harz, northern Germany; see Hess 2014). K–Y. Upper Oxfordian (Couches d’Effingen, bifurcatus ammonite Zone, stenocycloides ammonite Subzone), Savigna, near Orgelet, Département du Jura, France (Gale 2011b). Abbreviations: d = distal; p = proximal. See Fig. 3 for detailed morphological terminology. Scale bars: A–J = 0.2 mm; K–Y = 0.5 mm.