Talexirhynchia, a new rhynchonellid genus from the Jurassic Ethiopian Province of Jordan

Abstract

A new genus and species of a rhynchonellide brachiopod from the Jurassic of Jordan, Talexirhynchia kadishi gen. et sp. nov., is described. The specimens were collected from the Mughanniyya Formation (Callovian) of Wadi Zarqa from alternating claystones, siltstones, and marly limestones with minor dolomite, dolomitic limestone, and coquinas that represent the upper part of the Jurassic sequence in Jordan. The environment of deposition was neritic; food supply and light were unlikely to have been limiting factors. The specimens are related to Ethiopian-Somali taxa and are consistent with the endemism that characterizes the rhynchonellide brachiopod faunas of the Jurassic Ethiopian Province. Specimens of Talexirhynchia lived with the umbo in an upright position directed toward the seafloor or with the dorsal valve slightly above the ventral valve. Juveniles were attached to the seafloor by the pedicle; carbonate shell material as well as other debris scattered on a limy substrate, such as shells and rocks, could have served as an attachment site for juveniles. With increasing growth, the loss of the pedicle and a semi-infaunal position resulted in an increasingly incurved ventral umbo that concealed the foramen.