First bryozoan fauna from a tropical Cretaceous carbonate: Simsima Formation, United Arab Emirates–Oman border region

Twenty species of bryozoans are described from the Simsima Formation (Late Campanian–Maastrichtian) at six sites in the United Arab Emirates–Oman border region, extending from Jebel Huwayyah in the south to Jebel Faiyah in the north. Most encrust rudists and algal rhodoliths. Although surface preservation is poor to moderate, sufficient material is available to warrant the description of four new species: Conopeum wilsoni sp. nov., Wilbertopora cheethami sp. nov., Tyloporella smithi sp. nov., and Monoceratopora whybrowi sp. nov. A survey of latest Cretaceous bryozoan faunas shows the Simsima bryozoan fauna to be unusual in coming from a tropical palaeolatitude. Indeed, the only other described Campanian–Maastrichtian bryozoan fauna from the Cretaceous tropics comes from the underlying Qahlah Formation. Compared with contemporaneous bryozoan faunas at higher latitudes in the northern and southern hemispheres, the Simsima fauna contains few erect taxa but the genera present are all found in these higher latitudes; there is no indication of tropical endemic genera, or of early appearances of genera that later spread beyond the tropics.

► Twenty bryozoan species are described from the Maastrichtian Simsima Formation. ► Four new species of cheilostome bryozoans are introduced. ► The first tropical carbonate bryozoan fauna of Cretaceous age to be described. ► Dominated by cheilostomes as is typical for faunas of latest Cretaceous age. ► Composition of the Simsima fauna resembles coeval faunas from higher latitudes.