A finfoot from the Late Miocene of Toros Menalla (Chad, Africa):: Palaeobiogeographical and palaeoecological implications

A fossil humerus from the hominid fossiliferous area of Toros Menalla (ca 7 Ma, Chad, Africa) belongs to the Heliomithidae (Aves, Gruiformes). It is the second documented fossil record for the family, and the first in the Old World. It is compared with all the living species: the Sungrebe (Heliornis fulica), the Masked Finfoot (Heliopais personata) and the African Finfoot (Podica senegalensis). It belongs to the genus Heliopais, and is very similar to the only species H. personata. The Masked Finfoot appears to have evolved little morphologically since the Miocene. This poorly known and threatened genus and species is today confined to tropical South-East Asia. Its presence in the Late Miocene of Chad is a further Asian element in the late Neogene African avifaunas. Today the distribution of Heliopais is highly relictual, and some Heliomithidae will certainly be encountered in the Paleogene and the Miocene deposits of the Palearctic region. The African Finfoot is today the Heliomithidae geographically the closest to the site area, and occurs in forested regions south of the Sahelian area. Apparently, this genus was already absent further north, where the Asian genus was present, in the Late Neogene. Palaeoecologically, the presence of this Heliomithidae is indicative for Toros Menalla of a freshwater body with thick overhanging vegetation, and partly forested edges. This kind of precise indication about a component of the palaeoenvironment is critical for the study of hominid sites and early hominid evolution. A growing number of fossil birds from African hominid localities is yielding important clues regarding biogeography and environment. (c) 2005 Elsevier B.V. All rights reserved.