Nucula sp.

Hryniewicz, Krzysztof, Amano, Kazutaka, Bitner, Maria Aleksandra, Hagström, Jonas, Kiel, Steffen, Klompmaker, Adiël A., Mörs, Thomas, Robins, Cristina M. & Kaim, Andrzej, 2019, A late Paleocene fauna from shallow-water chemosynthesis-based ecosystems, Spitsbergen, Svalbard, Acta Palaeontologica Polonica 64 (1), pp. 101-141 : 109-110

? Nucula sp.

Fig. 7A .

Material.— One specimen ( ZPAL V.48/10), poorly preserved internal mold from the upper Paleocene of Fossildalen , Spitsbergen, Svalbard .

Measurements.— ZPAL V.48/10: L, 4.0 mm; H, 2.9 mm; W, 2.2 mm.

Description.—Shell small, well-inflated, ovate, equivalve, inequilateral. Antero-dorsal margin long and straight, passing into rather acute anterior end; postero-dorsal margin also nearly straight, sloping steeply into bluntly pointed posterior end; ventral margin broadly arcuate. Inner side of ventral margin finely crenulate. Posterior adductor muscle scar ovate, but anterior one not visible. Hinge and pallial sinus unknown.

Remarks. —The present species is similar to Nucula nucleus Linnaeus, 1758 ) in its shell outline and ventral crenulation. However, attribution to any particular species is not possible because the hinge could not be observed.

Figures

Fig. 7. Non-chemosymbiotic protobranch bivalves from the upper Paleocene, Basilika Formation, Fossildalen (A–E, G, I–K) and Zachariassendalen (F, H), Spitsbergen,Svalbard.A.?Nucula sp., ZPAL V.48/10,internal mold of right valve.B.?Malletia sp., ZPAL V.48/11, right valve.C, D.Neilonella sp.C. ZPAL V.48/12, left valve sculptured by fine commarginal ribs. D. ZPAL V.48/13, partial shell, right valve (D1), dorsal view of both valves (D2). E–K. Yoldiella spitsbergensis Amano sp. nov. E. Holotype, ZPAL V.48/17, internal mold, right valve (E1), hinge part (E2). F. Paratype, NRM-PZ Mo 186241, silicified shell, hinge part (F1), outer surface (F2). G. Paratype, ZPAL V.48/18, internal mold, right valve (G1), hinge part (G2). H. Paratype, NRM-PZ Mo 186242, silicified shell, right valve. I. ZPAL V.48/19, internal mold, left valve. J. ZPAL V.48/20, partial shell, left valve. K. ZPAL V.48/21, partial shell, partly preserved outer surface, left valve.