Trace fossils of the Upper Eocene–Lower Oligocene transition of the Manipur, Indo-Myanmar Ranges (northeast India)

A detailed ichnological analysis, for the first time, has been preformed on Upper Eocene-Lower Oligocene Transition of Manipur, Indo-Myanmar Ranges (Northeast India). Previous trace fossil analyses in India are scarce and usually poorly detailed, especially with respect to Cenozoic materials. Sediments from the Disang and Barail groups contain a relatively abundant and moderately diverse trace fossil assemblage that has been characterized at the ichnogenus and ichnospecies level. ?Arenicolites Salter 1857, Helminthopsis tenuis Ksiazkiewicz 1968, Ophiomorpha nodosa Lundgren 1891, Phycodes palmatus (Hall 1852), Planolites montanus Richter 1937, Rhizocorallium jenense Zenker 1836, Thalassinoides paradoxicus (Woodward 1830) and Skolithos linearis (Haldeman 1840) have been described therein in detail, most of them for the first time in the Manipur state. This ichno-assemblage represents the record of classical Skolithos and/or Cruziana ichnofacies, being characteristic of a shallow-marine environment, with occasional high-energy.