Late Ordovician scolecodonts and chitinozoans from the Pin Valley in Spiti, Himachal Pradesh, northern India

Abstract

The end of the Ordovician witnessed major perturbations in the ecosystem, seriously affecting global marine biodiversity. Nevertheless, some marine organism groups and their crisis-bound palaeogeographic distribution are still understudied. Among the outliers are eunicid polychaetes, even though they flourished and diversified extensively during the Ordovician. A collection of seven genera of jaw-bearing polychaetes, including the new ramphoprionid genus Spitiprion Tonarová, Suttner, & Hints, with type new species of Spitiprion khannai Tonarová, Suttner, & Hints, is described here from Katian (Upper Ordovician) deposits of Spiti, northern India. The new species is preserved as isolated maxillae and a jaw cluster, and 3D models of the maxillary apparatus are reconstructed based on submicron-CT. Along with the scolecodonts, a low-diversity assemblage of chitinozoans was recovered, comprising five genera. The most common chitinozoan species are Acanthochitina cf. cancellata and Spinachitina suecica.

Keywords

• polychaeta
• eunicida
• ramphoprionidae
• chitinozoa
• organic-walled microfossils
• early palaeozoic
• gondwana
• submicron-ct