Original paper

Occurrences, age and paleobiogeography of rare genera Phlycticeras and Pachyerymnoceras from South Tethys

Jain, Sreepat


New data on two rare genera (Phlycticeras and Pachyerymnoceras) from the Callovian (Middle Jurassic) sediments of Kachchh, western India are presented with an update on their South Tethyan occurrences. This paper documents the earliest occurrence of the genus Phlycticerasfrom the entire south of Tethys (P. polygonium var. polygonium[M]) from latest Early Callovian sediments (= Proximum Subzone, Gracilis Zone). Further, in light of the new taxonomic data, the previously recorded early Middle Callovian P. gr. pustulatum [M] is reevaluated as also all other Phlycticeras occurrences from the Indian subcontinent. Data suggests that in Kachchh, Phlycticeras has a long range from the latest Early to Late Callovian interval. Additionally, two new macroconch species of Pachyerymnoceras are also described and illustrated from Late Callovian sediments. A critical review of previous records suggests that in Kachchh, Pachyerymnoceras is restricted to the Submediterranean interval of the Collotiformis-Poculum subzones of the Athleta Zone. A note on the paleobiogeography and probable migratory routes of these two genera to India and elsewhere is also suggested.


kachchhlate callovianphlycticerasmiddle jurassicpachyerymnoceras