Triassic ostracods from the southeastern Tethys: the Timor-Leste record

Marine ostracods are reported for the first time from Triassic lithostratigraphic units exposed in Timor-Leste that accumulated in northeastern Gondwana basins along the proto-Australian plate sector. Seventy-two species distributed across 22 genera and 10 families are recognized, including four new species. Though of limited biostratigraphical significance, the implications of the recovered taxa are discussed to further improve the previously proposed integrated microfossil database. As a whole, ostracod communities spanning the studied Triassic deposits are indicative of outer neritic settings, likely associated with peculiar palaeoenvironmental conditions. Whilst the Babulu Formation (mid-Anisian to lower Norian) community comprises some taxa typical of bathyal settings, an outer neritic setting is favoured. Carnian Aitutu Formation (lower Carnian to lower Rhaetian) strata accumulated within a neritic setting, likely shallower than that of the Babulu Formation. The Wai Luli Formation (mid-Rhaetian to Lower Jurassic) assemblage also suggests an outer neritic setting, yet likely shallower than the Babulu Formation. The palaeobiogeographical affinities of the studied communities are analysed for the Carnian and Rhaetian, indicating that ostracods from southeastern peri-Tethys were integrally part of the wider peri-Tethyan realm. Our study considerably increases knowledge of southeastern peri-Tethyan marine ostracod diversity in the Outer Banda Arc, but new data are needed to resolve faunal links with the northwestern margin of the Australian shelf. <i>Marie-Béatrice Forel* [[e-mail]], Muséum national d’Histoire naturelle, CR2P, MNHN-CNRS-Sorbonne Université, 8 rue Buffon (CP38), 75005 Paris, France; Eujay McCartain [[e-mail]], School of Earth Sciences, The University of Western Australia, 35 Stirling Highway, Perth, Western Australia 6009, Australia; David W. Haig [[e-mail]], Oceans Institute, The University of Western Australia, 35 Stirling Highway, Perth, Western Australia 6009, Australia</i>