Ostracoda (Crustacea) from the Lower Jurassic of northeastern Thailand: stratigraphic and paleoenvironmental implications

Abstract

Freshwater ostracods were recovered from limestone strata belonging to the Nam Phong Formation exposed at Ban Non Tum section in Chaiyaphum Province, northeastern Thailand. The examined rocks were collected above the oldest known dinosaur footprints site in Thailand. All recovered ostracods belong to the Superfamily Darwinuloidea and were attributed to three species: Suchonellina sarytirmensis (Sharapova) in Mandelstam, 1947, Suchonellina. sp. A and Suchonellina sp. B. The ostracods represent the first known record of Jurassic darwinuloideans in Southeast Asia. The ostracod assemblage and microfacies are indicative of deposition in a shallow and low energy fluvio-lacustrine regime.