Paleogene nummulitid foraminifera from the Indonesian Archipelago: a review

Previous records of nummulitid foraminifera without chamberlets from Indonesia and contiguous areas are reviewed, with the emphasis on species previously assigned to the genera Nummulites Lamarck, 1801, Assilina d’Orbigny, 1826 and Ranikothalia Caudri, 1934. Of the 70+ species referred to these genera, sixteen are here considered valid. Assilina orientalis Douvillé, 1912b, A. leymeriei d’Archiac & Haime, 1853, A. granulosa d’Archiac, 1846, A. spira de Roissy, 1805,, A. exponens Sowerby in Stykes, 1840, and Nummulites (A.) umbilicata Rutten in Waterschoot van der Gracht, 1915 are assigned to Planocamerinoides Cole, 1957, while Camerina taballarensis Caudri, 1934, Nummulites pengaronensis Verbeek, 1871, N. beaumonti d’Archiac & Haime, 1853, C. crasseornata Henrici, 1934, C.cf. globula Leymerie, 1846 sensu Henrici, 1934], and Lenticulites variolaria Lamarck, 1804 are transferred to Palaeonummulites Schubert, 1908. Six species of Nummulites (N. boninensis Hanzawa, 1947, N. djokdjokartae (Martin, 1881), N. fichteli Michelotti, 1841, N. javanus Verbeek, 1891,, N. martini n. sp. and N. subbrongniarti Verbeek, 1871), seven of Palaeonummulites (P. beaumonti, P. crasseornatus, P. pengaronensis, P. songoensis n. sp., P. taballarensis. P. variolarius and P. sp.), and three of Pl. umbilicata; Planocamerinoides (Pl. orientalis, and PL sp.) from Eocene-Oligocene strata of the Indonesian Archipelago are described and illustrated. A revision of museum collections as well as a study of newly collected Paleogene larger nummulitids from Indonesia, coupled with new biostratigraphic data based mainly on calcareous nannoplankton, planktonic foraminifera and dinoflagellates, plus preliminary strontium isotope dates, have now resulted in a more refined picture of the stratigraphic/palaeobiogeographic distribution of Paleogene nummulitids in the region. Deposits of Early and early Middle Eocene age are rare in Indonesia; younger Paleogene sediments are commoner. Subsequent to the inundation of the Sunda Shelf at c. 45 Ma, shallow-marine carbonates became more widely distributed. In the best documented part of Indonesia, i.e. Java, strata of late Bartonian to early Rupelian age are missing. Upper Bartonian to lower Rupelian strata are represented in sections in Borneo and Sulawesi, although there Priabonian and lower Rupelian deposits often are poorly fossiliferous.