New records of nautiloid and ammonoid cephalopod fossils in peninsular Thailand

Abstract

Thirty species of nautiloids and ammonoids were identified based on the material collected from peninsular Thailand. Ordovician nautiloids: a sactorthoceratid nautiloid (Sactorthoceras banestanensis) from Changwat Satun, from the western part of the peninsula and a ruedemannoceratid nautiloid (Mediganella magna), from Changwat Nakhon Si Thammarat from the eastern part of the peninsula. Devonian-Carboniferous ammonoid: Neoglyphioceras subcirculare from Changwat Satun. Triassic nautiloids: two orthoceratid nautiloids (Michelinoceras sp. A and Tienoceras sp. A), and two syringonautilid nautiloids (Syringoceras barrandei and Javavionautilus heterophyllus) from Changwat Phatthalung, in the eastern part of the Peninsular. Twenty-four species of ammonoids were collected from the same locality: one ophiceratid (Ophiceras connectens), one flemingitid (Xenodiscoides perplicatus), one meekoceratid (Juvenites canadensis), two paranannitids (Arianites musacchi and Epiceltites genfii), two ussurids (Ussuria sp. A and Ussaria sp. indet.), one noritid (Bosnites clathratus), one acrochordiceratid (Paracrochordiceras sp. indet.), nine ceratitids (Kellnerites bosnensis, Halilucites sp. A, Halilucites sp. B, Eutomoceras aff. laubei, E. dunni, Eutomoceras sp. A, E. sp. B, E. sp. C, E. sp. D), one hungaritid (Hungarites sp. A), one aplococeratid (Aplococeras parrus), one celtitid (Indoceltites trigonalis), one nannolytoceratid (Audaxlytoceras audax) and one protetragonitid (Protetragonites sp. A). All these cephalopods are recorded for the first time in Thailand.