BRACHIOPOD ENDEMISM IN THE JURASSIC ETHIOPIAN FAUNAL PROVINCE

Endemic brachiopods are those that can be differentiated from their ancestral populations by unique morphologies (apomorphies) and are restricted to a specific environment or region. Workers (Weir, 1929; Muir-Wood, 1935) recognized endemic brachiopods in the Ethiopian Faunal Province (EFP): Somalirhynchia africana, Daghanirhynchia daghaniensis, Somalithyris bihendulensis, Striithyris somaliensis, Bihenithyris barringtoni, and B. weiri. In the Jurassic many of Cooper’s (1987) Saudi Arabian brachiopods fall into this category as do taxa from northern Sinai, Jordan and Israel that have been determined during the past several decades. These endemics are typified by: Echyrosia, Eurysites, Toxonelasma, Goliathyris, Jordanithyris, and Polyplectella. Endemic brachiopods also helped define the EFP which was tropical to subtropical and very different from the Boreal Faunal Province to the north. The faunas of northern Sinai, Saudi Arabia, Jordan and Israel lie at the northernmost part of the Indo-African Faunal Realm and enable workers to more clearly recognize faunal realm boundaries. Liu et al. (1998) determined that the northern boundary of the Ethiopian Bivalve Province is quite distinct when based on species. Further analysis of the paleobiogeographic brachiopod data in the EFP will enable us to more accurately define its northern boundary and support the postulated sequence of rifting within the southern Tethyan Platform. This rifting resulted in the isolation of the EFP from its northern boreal counterpart by the completion of the Tethyan-North Atlantic Ocean divide.