Jurassic bivalves from the Spiti area of the Himalayas, northern India
Author
Fuersich, Franz T.
https://orcid.org/0000-0002-0844-9297
Universitaet Erlangen-Nuernberg, GeoZentrum Nordbayern, FG Palaeoumwelt, Lowenichstrasse 28, 91054 Erlangen, Germany
franz.fuersich@fau.de
Author
Alberti, Matthias
State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Centre for Research and Education on Biological Evolution and Environment and Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, China
Author
Pandey, Dhirendra K.
https://orcid.org/0000-0002-7721-9604
Department of Earth and Environmental Science, KSKV Kachchh University, Bhuj, India
Author
Ayoub-Hannaa, Wagih S.
Geology Department, Faculty of Science, Minufiya University, El-Minufiya, Shibin El Kom, Egypt
text
Zitteliana
2022
2022-08-11
96
153
178
http://dx.doi.org/10.3897/zitteliana.96.87253
journal article
http://dx.doi.org/10.3897/zitteliana.96.87253
2747-8106-96-153
191199E07F3E4E09A3774ADFBF93A248
AFA9059B36235BFF9BA3E9B7BE816DC1
Camptonectes (Camptochlamys) obscurus (J. Sowerby, 1818)
Plate 3, fig. 13
Pecten obscura
*1818
Pecten obscura
- J. Sowerby: 3, pl. 205, fig. 1.
Camptonectes indicus
1852
Camptonectes indicus
sp. nov. - Cox: 25, pl. 3, figs 1-4.
Camptonectes Germaniae
?1939
Camptonectes Germaniae
(
d'Orb
.) - Stefanini: 171, pl. 19, fig. 11.
1956 Camptonectes indicus
Cox - Agrawal: 77, pl. 9, fig. 5.
1968 Camptonectes indicus
Cox - Maithani: 505, pl. 33, fig. 6.
1979 Camptonectes (Indonectes) obscurus
(J. Sowerby) subgen. nov. - Kanjilal: 120, fig. 6.
1983 Camptonectes (Indonectes) obscurus
(J. Sowerby) - Singh and Jaitly: 47, pl. 1, fig. 5.
1995 Camptonectes (Camptochlamys) obscurus
(J. Sowerby, 1818) - Jaitly et al.: 196, pl. 19, figs 7-8.
Material.
A single left valve partly in shell preservation, seen from the interior, from the lower member near the pass to Tashigeng (SNSB-BSPG 2020 XCIX 13).
Description.
Shell suboval, higher than long (H: 22.2 mm, L: ~20 mm), moderately inflated, anteroventral, posteroventral and ventral margins rounded and regularly curved; antero- and posterodorsal margins of disc sub-straight. Anterior auricle large, distinctly set off from anterodorsal flank, which is more steeply sloping than posterodorsal flank. Tip of umbo and posterior auricle missing, anterior and posterior margin of disc also not fully preserved. Disc ornamented with thin, sharp, regularly spaced commarginal ribs and numerous thin divaricate radial grooves, separated by smooth, flat intervals about twice the width of the grooves. Umbonal area with thin radial riblets. Anterior auricle covered with spaced commarginal riblets intersected by thin radial riblets, creating a reticulate pattern.
Remarks.
The specimen closely corresponds to the diagnosis of
Camptonectes (Camptochlamys) obscurus
as given by
Johnson (1984)
. So far, the species has not been recorded from the Himalayan shelf of the southern Tethys, but it occurs in the Callovian of the Kachchh Basin further south (
Cox 1952
;
Jaitly et al. 1995
) and possibly also in other parts of the Ethiopian faunal province (e.g., as
Camptonectes germaniae
(
d'Orbigny
, 1850) in Somalia;
Stefanini 1939
p. 171, pl. 19, fig. 11).