Malayomaorica? sp.

Fuersich, Franz T., Alberti, Matthias, Pandey, Dhirendra K. & Ayoub-Hannaa, Wagih S., 2022, Jurassic bivalves from the Spiti area of the Himalayas, northern India, Zitteliana 96, pp. 153-178 : 153

Malayomaorica? sp.

Plate 3, figs 6-10

Material.

Numerous right and left valves preserved as composite moulds or with remains of shell, generally strongly compacted and often fragmented, from the upper member close to Demul Pass (SNSB-BSPG 2020 XCIX 51-52).

Description and remarks.

The poorly preserved specimens are characterized by a feebly inflated right valve and a strongly inflated left valve. The height distinctly exceeds the length of the shell, which is slightly oblique, the ventralmost part being posterior of the mid-line. The anterior margin is well-rounded, the posterior margin sub-straight, the ventral margin strongly curved. The right valve anterior auricle is directed towards the left valve; the byssal notch is well-developed. The surface of the shell is covered with faint radial riblets in addition to faint commarginal growth rugae.

The different outline and the radial riblets distinguish the material from Buchia . Due to the poor preservation and lack of detailed hinge information the specimens are only tentatively placed in Malayomaorica . This is the first documentation of the genus from the Indian Himalayas.

Figures

Plate 3. (1, 2) Bositra buchii (Roemer, 1836). Composite moulds from the lower member at Langza. 1. a, articulated specimen in butterfly position, dorsal view (SNSB-BSPG 2020 XCIX 18 a); b, c, single valves, lateral view (SNSB-BSPG 2020 XCIX 18 b). 2. External mould of right valve (SNSB-BSPG 2020 XCIX 19). (3) Australobuchia spitiensis (Holdhaus, 1913). Composite mould of articulated specimen from the middle member, roadside close to Komic; right valve view (SNSB-BSPG 2020 XCIX 43). (4 - 5) Australobuchia blanfordiana (Stoliczka, 1866). upper member close to Demul Pass. 4. Right valve (SNSB-BSPG 2020 XCIX 46). 5. Right valve (SNSB-BSPG 2020 XCIX 45). (6 - 10)? Malayomaorica sp. upper member close to Demul Pass. 6. Left valve (SNSB-BSPG 2020 XCIX 51 a). 7. Right valve interior (SNSB-BSPG 2020 XCIX 52). 8. Fragment of right valve (SNSB-BSPG 2020 XCIX 51 b). 9. Left valve (SNSB-BSPG 2020 XCIX 51 c). 10. Fragment of right valve (SNSB-BSPG 2020 XCIX 51 d). (11) Entolium (Entolium) corneolum (Young & Bird, 1822). Internal mould of a left valve from the lower member at Langza (SNSB-BSPG 2020 XCIX 15). (12) Propeamussium (Propeamussium) sp. Internal mould of a small fragment from the lower member at Langza (SNSB-BSPG 2020 XCIX 12). a, natural size; b, enlarged. (13) Camptonectes (Camptochlamys) obscurus (J. Sowerby, 1818). Left valve interior from the lower member near the pass to Tashigeng (SNSB-BSPG 2020 XCIX 13).