Malletia 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 : 110

? Malletia sp.

Fig. 7B .

Material.— One specimen ( ZPAL V.48/11), poorly preserved shell from the upper Paleocene of Fossildalen , Spitsbergen, Svalbard .

Measurements.— ZPAL V.48/11: L, 4.7 mm; H, 3.2 mm; H/L, 0.68.

Description.—Shell small, weakly inflated, elongate-ovate, inequilateral. Surface smooth without fine growth lines. Antero-dorsal margin short, sloping steeply into semicircular anterior margin; postero-dorsal margin long, nearly straight, forming bluntly pointed posterior end with broadly arcuate ventral margin. Beak not very prominent, located at anterior third of shell length.

Remarks.—The investigated specimen is doubtfully classified in Malletia based on its weakly inflated shell and outline. Its outline is very similar to Malletia sp. from the Selandian (middle Paleocene) Katsuhira Formation in eastern Hokkaido, Japan ( Amano and Jenkins 2017: fig. 19). However, the present species is smaller and taller than the Katsuhira species (L, 10.4–10.9 mm; H, 5.5–6.4 mm; H/L, 0.53–0.58).

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.