Melanopsis from the Pleistocene site of ’Ubeidiya, Jordan Valley: direct evidence of early hybridization (Gastropoda: Cerithioidea)

摘要: ’Ubeidiya is a 1.4 Myr-old Lower-Pleistocene site in the Jordan Valley. Its rich Melanopsis fauna was found to include five species: buccinoidea, costata, turriformis, phanesiana obediensis and multiformis. These species their conchiometrics are described. M. buccinoidea costata occur Levant also today whereas p. multiformis extinct. findings suggest considerable faunal connections between Jordan, Orontes perhaps Rodhos during lower Pleistocene. During late Miocene, when Mediterranean Sea level dropped, coastal-plain freshwater habitats could have expanded then invaded Rift Valley via coastal rivers. In addition they reached later, Species frequencies of throughout ‘Ubeidiya three’ landscapes’: an early period dominated by later one upper obediensis. It reasonable speculate that landscape represents spring or deep lake with nearby stream; shallow, nonturbulent, well-aerated slow current; turbulent, lake. Intermediates were costata. Their low frequency chrono-distribution hybrids, rather than evolutionary transitions species. The Myr old fossils may be earliest direct evidence hybridization among molluscs nature, still going on same region aquatic system, hybrid populations act as filters prevent introgression most genes, but allow others disperse into range parent © 2002 Linnean Society London, Biological Journal Society, 2002, 75, 39–57.