Biostratigraphic indices for Lower Jurassic carbonate-platform deposits (Perdido Group), Overthrust Terrane Association, Timor-Leste

•This is the oldest unit within allochthonous Overthrust Terrane Association (OTA).•Bahamian-type facies are represented with few macrofossils but distinct Foraminifera.•Age is from foraminiferal species known from Europe and North Africa.•Five localities are within Sinemurian–Pliensbachian are described.•Coeval Bahamian-type limestones are not known elsewhere in region. Lower Jurassic carbonate-platform deposits in Timor-Leste have been subject to much controversy. The Perdido Group contains the Bahamian-type facies shallow-water limestone of the Lower Jurassic that had been mixed with an upper Oligocene–lowest Miocene carbonate unit in Audley-Charles's Cablac Limestone. Foraminiferal assemblages from five sites in the Perdido Group are used to confirm a Sinemurian–Pliensbachian age. Species recorded for the first time from Timor and from the broader region, are Biokovina sp., Bosniella oenensis Gušić, Endotriadella ifranensis Bassoullet, Boutakiout, Vachard, Lituosepta recoarensis Cati, Palaeocyclammina complanata Bassoullet, Boutakiout and Echarfaoui, Planisepta compressa (Hottinger), and Radoicicina ciarapicae Gale, Barattolo and Rettori. Previously Siphovalvulina spp. and Meandrovoluta asiagoensis Fugagnoli and Rettori were described from the group. These species allow distinction between the Perdido Group (part of the Overthrust Terrane Association in Timor-Leste) and the carbonate-platform Upper Triassic Bandeira Group (part of the East Gondwana Interior Rift Association). No equivalent facies coeval with the Perdido Group and with similar foraminiferal assemblages have been recognized in the Indonesian, Malayasian, Timor-Leste, or north-west Australian regions. The closest known Sinemurian–Pliensbachian occurrence containing some of the species found in the Perdido Group, is in Western Thailand, with a fauna including Lituosepta cf. recoarensis.