Ancient DNA forces reconsideration of evolutionary history of Mediterranean pygmy elephantids.

During the Pleistocene pygmy elephantids, some only a quarter of their ancestors' size, were present on Mediterranean islands until about 10,000 years ago (y.a.). Using a new methodology for ancient DNA (aDNA) studies, the whole genomic multiple displacement amplification method, we were able to retrieve cytochrome b (cytb) DNA fragments from 4200 to 800,000 y.a. specimens from island and mainland samples, including pygmy and normal-sized forms. The short DNA sequence (43 bp) retrieved from the 800,000 y.a. sample is one of the oldest DNA fragment ever retrieved. Duplication of the experiments in two laboratories, the occurrence of three diagnostic sites and the results of the phylogenetic analyses strongly support its authenticity. Our results challenge the prevailing view that pygmy elephantids of the eastern Mediterranean originated exclusively from Elephas, suggesting independent histories of dwarfism and the presence of both pygmy mammoths and elephant-like taxa on these islands. Based on our molecular data, the origin of the Tilos and Cyprus elephantids from a lineage within the genus Elephas is confirmed, while the DNA sequence from the Cretan sample falls clearly within the mammoth clade. Thus, the name Mammuthus creticus rather than Elephas creticus, seems to be justified for this form. Our findings also suggest a need to re-evaluate the evolutionary history of the Sicilian/Maltese species, traditionally included in the genus Elephas.

Inference of a radiation in Mastus (Gastropoda, Pulmonata, Enidae) on the island of Crete.

The Mediterranean land snail genus Mastus (Beck, 1837) is highly divergent. Thirty-two Mastus species have been recorded throughout the genus range, and 23 of them are endemic to the islands of the Aegean Sea and mainland Greece. Of these, all 16 Mastus species reported from Crete are endemic to this island. A robust molecular phylogenetic framework based on mitochondrial and nuclear genes (1623 bp) allowed us to explore the temporal diversification pattern of lineages, using molecular clock approaches. Our results showed an initial radiation in the evolutionary history of the Cretan lineage, followed by a subsequent slowdown of lineage splitting rate. Using a dated major vicariant event of the Aegean area, we estimated the absolute time of the radiation event and proposed a biogeographic scenario accounting for the observed pattern. Additionally, we tried to infer the processes that led to the divergence of the Cretan Mastus species, by applying comparative methods in phylogenetically informated context. Overall, our results favoured a nonecological radiation scenario in the Cretan Mastus species due to an allopatric divergence of secondary sexual characters.

Molecular phylogeny of the extinct pleistocene dwarf elephant Palaeoloxodon antiquus falconeri from Tilos Island, Dodekanisa, Greece.

A partial sequence of cytochrome b (228 bp) gene of mitochondrial DNA was successfully determined from rib bones of the dwarf elephant Palaeoloxodon antiquus falconeri BUSK, which were excavated from Charkadio cave of the island of Tilos, Dodekanisa, Greece. This is the first report of DNA sequence of a dwarf elephant. The sequences were used to examine the phylogenetic relationships among Elephantidae. Phylogenetic trees reconstructed by the neighbor-joining and maximum parsimony methods provided identical topologies. The results support the "Palaeoloxodon-Elephas" clade, which is consistent with previous morphological reports according to which Palaeoloxodon is more closely related to Elephas than to Loxodonta or Mammuthus.