Abstract
Forty-six Callovian macrofaunal species including 13 brachiopods, 19 bivalves, and 14 gastropods were collected from three surface sections - Shaib Al Hisyan, Khashm Al Giddiyah, and Dirab - in the Tuwaiq Mountain Formation around Riyadh City in central Saudi Arabia. The fauna is discussed systematically and with respect to biostratigraphic implications and its paleobiogeographic distribution. Four macrobiozones with two barren intervals are identified. These zones are from base upward: Pholadomya (Bucardiomya) lirata, Barren interval (1), Sphringanaria capax, Pholadomya inornata, and Coral Zone of Middle Callovian age and Barren interval (2) of Middle to Late Callovian age. The paleobiogeographic distribution of the fauna confirmed the endemism along the southern Tethyan margin of the Ethiopian Province. Copyright 2016 Saudi Society for Geosciences