Callovian–Oxfordian bivalves from central Saudi Arabia: Systematic paleontology and paleobiogeography (original) (raw)

Two hundred and seventy eight specimens of fossil bivalves were collected from the Tuwaiq Mountain Limestone (Callovian) and the Hanifa Formation (Oxfordian), Central South Arabia. Of all the outcrops studied, the Khashm al Qaddiyah contains the richest assemblage of the bivalves (49 %), as regards variety and frequency; followed by Dirab (27 %), Jabal al Abakkayn (13 %) and Maáshabah (11 %). Twenty bivalve species have been identified and systematically described. They belong to fourteen genera, twelve families and nine orders. Among these species, six Callovian species; Grammatodon (Cosmetodon) elongatum (J.