Species / Maussenetia Dimorphospira
Stromboidea
Original Description of Chenopus (Maussenetia) dimorphospira Cossmann & Pissarro, 1909
Locus typicus: India. “Jhirak: zone 3, zone 4. According to Mr. Vredenburg, this species, or one very closely related, occurs also abundantly, as casts, in the Laki limestone overlying the Ranikot group.” Stratum typicum: lower Eocene. “upper Ranikot.” “Comparision with other species. - The fragments originally sent to us (Pl. IV, figs. 26-28) recalled Sulcogladius on account of their ornamentation and keel, both of which closely resembles the same features in Rostellaria goniophora Bellardi, the type of the subgenus Sulcogladius. But this impression was dispelled by our examination of a much more complete specimen subsequently forwarded to us by Mr. Vredenburg, showing the columellar callus, and the remnants of a wing extending up to the apex of the spire (Pl. VIII, figs 4, 4a): the shell must evidently be classified with the subgenus Maussentia, Cossm. (Essays Pal. Comp., 1904, fasc. VI, p. 118), the type of which is M. staadti, Cossm., characterised by the same ornamentation, with the same keel and gibbosity on the body-whorl. Nevertheless, Chenopus dimorphospira is much more ventricose than the European species, and its threads are more regular. No comparison can be established in the case of the wing which has disappeared in the Indian specimens. It is very interesting to find in the Eocene of India, a representative of this paleocenic form from the Paris basin; perhaps it will ultimately be shown that the species of Sulcogladius from the nummulitics of the Mediterranean (none of which have yet been found with the wing preserved), will have to be united with Maussenetia, indicating stages in the migration of this form.” References |