NEW FOSSIL RATITE (AVES: PALAEOGNATHAE) EGGSHELL DISCOVERIES FROM THE LATE MIOCENE BAYNUNAH FORMATION OF THE UNITED ARAB EMIRATES, ARABIAN PENINSULA

Abstract

Fossil ratite eggshell fragments recovered from the Late Miocene Baynunah Formation, United Arab Emirates, are described as Diamantornis laini and as an aepyornithid-type eggshell fragment. D. laini has been previously reported from the Late Miocene of Namibia and Kenya, whereas aepyornithid-type eggshell is known from many Neogene deposits in Eurasia and Africa. The new fossils are the first eggshells of this age to be described from the Arabian Peninsula, and they constitute an informative addition to the faunal assemblage recovered from the Baynunah Formation. The discovery of D. laini from the Arabian late Late Miocene supports the concept of an Afro-Arabian eggshell biostratigraphy. The probable occurrence of this ootaxon at Lothagam, Kenya, suggests the age of the Baynunah fauna may be no younger than 6.5 Ma. Both the Baynunah and Lothagam records suggest a younger age range than that defined for D. laini on the basis of the biostratigraphy of the Tsondab sequence of Namibia (10–8 Ma). The addition of D. laini to the Arabian Late Miocene faunal list strengthens this region’s paleobiogeographic affinity to Africa, specifically sub-Saharan Africa, to the exclusion of Europe and Asia. The aepyornithid-type is a less well-known eggshell type that in morphology resembles Aepyornis, the recently extinct Malagasy elephant bird. Aepyornithid-type eggshell has been reported throughout Miocene and Pliocene sequences in Africa and Asia, and its first occurrence may be as old as the Eocene of China. The systematics of fossil ratite eggshell taxa is reviewed and considered.