Search

Members of the Euphorbiaceae are ecologically important elements of Southeast Asian forests. Species of the pioneer tree genus Macaranga, which is also known for its association with ants, are often abundant in disturbed areas. Phylogenetic studies suggested a recent radiation of section Pachystemon which comprises the majority of obligate myrmecophytes within Macaranga. In the present study, we analyzed the genetic structure of three closely related species of this section (M. constricta, M. griffithiana, and M. motleyana) with the aim of resolving their controversial taxonomy and historical biogeography. Chloroplast DNA haplotypes proved to be species-specific and showed a strong phylogeographic pattern. Nuclear microsatellite data supported the taxonomic distinctness of M. griffithiana and M. motleyana, but gave ambiguous results for M. constricta. Genetic differentiation was stronger each within M. griffithiana and M. motleyana than between M. constricta and M. griffithiana, highlighting problems of defining species boundaries. We found no indication for introgression or hybridization events. The high intraspecific morphological variation of the Bornean endemic M. motleyana was partly reflected by similar patterns of genetic variation. The pronounced genetic structure indicates a comparatively long diversification for this species. In contrast, the weak genetic differentiation within M. griffithiana, as well as the widespread distribution of its most common chloroplast haplotype from peninsular Malaysia up to Indochina, indicates a recent expansion in this area. Despite their morphological similarity and close relatedness, all species possess their own specific ant-partners with a corresponding distribution pattern.

The molecular phylogeography of the viperine snake, Natrix maura (Linnaeus, 1758), was investigated using complete sequences of the mitochondrial cytochrome b gene and genomic ISSR-PCR fingerprinting. In a total of 120 samples, 44 unique cytochrome b haplotypes were found which defined three major genetic lineages associated with samples from Morocco, Tunisia and Europe, respectively. The same lineages were supported by nuclear data. A possible fourth lineage exists in southern Spain. Genetic distances of cytochrome b sequences between the three main lineages were in the range of 3.9–5.6%, suggesting independent evolution since the early Pliocene. Distinction of the three major lineages at the subspecies or species level is discussed to account taxonomically for the high intraspecific variation in the viperine snake. A more detailed analysis of the European samples based on genetic diversity indices and a network reconstruction suggests a complex Pleistocene history for the viperine snake in Europe. Clear differentiation was found between populations south and north of the central Iberian mountain ranges, suggesting Pleistocene glacial refugia both in the southern and northern Iberian peninsula. In the south, genetic diversity was associated with the main river valleys, whereas northern haplotypes were more broadly distributed, indicating gene flow or postglacial range expansions. Unexpectedly high levels of genetic variation in southeastern France and northwestern Italy would be compatible with the hypothesis of a glacial refugium north of the Pyrenees or in Italy. However, due to the dependence of N. maura on warm climates, the assumption of a northern refugium seems unwarranted. We believe that further sampling in northern Spain is likely to reveal genetically diverse populations which could have served as sources for postglacial recolonization of France and Italy.

The European pond turtle, Emys orbicularis (Linnaeus, 1758), is one of the world's most widely distributed chelonian species. We investigated its mitochondrial phylogeography and demography using ∼1300cyt b sequences from the entire range, with a focus on the eastern part, in particular on Turkey, where the species currently suffers massive losses. Coloration data from >1450 turtles were compared with mtDNA differentiation to assess the validity of the currently accepted subspecies from Turkey, the Black Sea Region, the Transcaucasus, and Iran. Our study region harbors considerable part of the mtDNA diversity of Emys, including a newly discovered lineage and 16 new haplotypes. In this area corresponding to approximately one-third of the entire distribution range, six out of the ten mitochondrial lineages and about half of all 72 haplotypes occur. Two mitochondrial lineages (VIII, X) are confined to small ranges along the southern coast of Turkey, another lineage (I) occupies the remainder of Turkey, the entire Black Sea Region, and the north-eastern part of the species’ range. In the south-western corner of the Black Sea and in the Aegean Region, two lineages (II, IV) occur that have their main distribution areas farther west. In the Transcaucasus and northern Iran, another endemic lineage (VII) is found. Lineage I is the largest and most diverse of all lineages and has its greatest diversity in Anatolia. Phylogeographic and demographic data suggest Anatolia as an ancient glacial refuge for turtles harboring mitochondrial lineages I, VIII and X, and that Anatolia and the Black Sea coasts constitute a hotspot for a younger burst of diversification within lineage I. These two regions correspond to the glacial refuge from which lineage I turtles recolonized more northerly parts of the range in the Holocene; lineage II represents an off-shoot of lineage I that became isolated in a westward-located refuge in the south-eastern Balkans during a previous Pleistocene glacial. Our data on coloration indicate that such characters have only limited value for delineating evolutionarily significant units. We propose to reduce the number of subspecies using mtDNA lineages as arbiter, and to recognize three subspecies as valid in Turkey, the Black Sea Region, the Transcaucasus and Iran: Emys orbicularis orbicularis (mtDNA lineage I); E. o. eiselti Fritz et al., 1998 (X); and E. o. persica Eichwald, 1831 (VII). However, the southern Turkish lineage VIII most probably represents an additional undescribed subspecies. Both southern Turkish endemics are critically endangered, with only three surviving populations of fewer than 30 adults each. We recommend establishing sanctuaries for them, and including them in the IUCN Red List.

The dice snake, Natrix tessellata (Laurenti, 1768), is a suitable study organism to address questions of Eurasian phylogeography due to its wide Palearctic distribution. We analysed complete mitochondrial cytochrome b sequences and nuclear ISSR-PCR fingerprints of more than 300 specimens representing nearly the entire geographic range. Nine major mitochondrial lineages were discovered based on mtDNA sequences. The three most basal lineages comprised populations from Iran, Jordan–Egypt, and Greece, respectively. Other lineages were associated with samples from the Turkish peninsula, the Caucasus, the Aral Sea, and eastern Kazakhstan. A sister-group relationship was found between two lineages from Crete and the European mainland. Assuming an evolutionary rate of 1.35% sequence divergence per million years, among-lineage p-distances of 1.7–8.4% suggest that intraspecific differentiation might date back as far as the Miocene/Pliocene transition 5–6 million years ago. The pattern of genetic differentiation in mitochondrial phylogeny with regard to Asia Minor and the region of the Aral Sea was not congruent with the results of the nuclear ISSR-PCR analyses, and suggests admixing within some mtDNA clades at contact zones. The taxonomic implications of the high intraspecific variation in the dice snake are discussed.