Научная статья на тему 'Molecular phylogeny and intraspecific differentiation of the Iranian and central Asian species in the genus Trapelus (Sauria: Agamidae) inferred from mitochondrial DNA sequences'

Molecular phylogeny and intraspecific differentiation of the Iranian and central Asian species in the genus Trapelus (Sauria: Agamidae) inferred from mitochondrial DNA sequences Текст научной статьи по специальности «Биологические науки»

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Ключевые слова
AGAMIDAE / TRAPELUS / T. AGILIS COMPLEX / MOLECULAR PHYLOGENY / INTRASPECIFIC DIFFERENTIATION / MITOCHONDRIAL DNA / IRANIAN PLATEAU / CENTRAL ASIA

Аннотация научной статьи по биологическим наукам, автор научной работы — Rastegar-Pouyani Eskandar, Rastegar-Pouyani Nasrullah, Joger Ulrich, Wink Michael

The steppe agamas of the genus Trapelus Cuvier, 1816, are an old clade of agamid lizards with an Afro-Arabian origin. The genus consists of about 14 15 species which are distributed from northwestern Africa, along the Saharan border, through the Near East to southwest and central Asia. They constitute one of the major components of the Iranian Plateau and central Asian fauna and are highly adapted to steppe, semi-deserts and desert environments. To date, published morphological and molecular phylogenetic hypotheses of Trapelus are only partially congruent, and the relationships within the genus are still far from clear. We investigated the phylogenetic relationships and intraspecific differentiation among the Iranian and Central Asian species of these lizards (69 individuals collected from 14 populations of four well-defined species and several unidentified specimens using two mitochondrial gene fragments (ND2 and cytochrome b)). The partition-homogeneity tests indicated that the combined dataset was homogeneous, and maximum-parsimony (MP), maximum-likelihood (ML) and Bayesian (BI) analyses were performed on this combined dataset. The trees reconstructed by different methods were generally very similar. Relationships among the examined species and populations were highly resolved. The basal position in the tree was always occupied by Trapelus ruderatus (= the formerly T. persicus) which in turn formed the sister taxon for populations of T. lessonae. The phylogenetic analysis together with genetic distances among the major clades suggested that, in the Iranian Plateau, T. agilis, genetically, represents a species complex containing at lease three well distinct taxonomic entities at the species level. The analyses also showed that, despite their vast distribution range, the Central Asian populations are genetically very homogenous, just representing a single taxonomic entity (i.e., T. sanguinolentus).

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Текст научной работы на тему «Molecular phylogeny and intraspecific differentiation of the Iranian and central Asian species in the genus Trapelus (Sauria: Agamidae) inferred from mitochondrial DNA sequences»

DeAgamis2: ВТОРОЙ МЕЖДУНАРОДНЫЙ СИМПОЗИУМ ПО АГАМОВЫМ ЯЩЕРИЦАМ

diverged but chromosomally and genetically distinct endemic species have been recognized - Japalura polygonata, J. swinhonis, J. brevipes, J. makii, and J. luei. All these species occur in the mainland Taiwan, with partial syntopy in various combinations. Of these, only J. polygonata also occurs in the Ryu-kyu Archipelago of Japan and is polytypic, consisting of four subspecies - J. p. xanthostoma from northern Taiwan, J. p. donan from Yonagunijima Island of the Southern Ryukyus, J. p. ishigakiensis from some other islands of the Southern Ryukyus, and J. p. polygonata from the Central Ryukyus. The karyotype consisting of 2n = 46 all telocentric chromosomes in a graded series is shared by all broadly ranging lowland (< 1,200 m asl.) populations of J. polygonata and J. swinhonis. In contrast, the remaining three species, all confined to montane habitats of mainland Taiwan (1,000 - 2,200 m asl.) exhibit remarkable karyotypic variations involving the chromosome number (2n = 40 in J. makii, and 36 in J. brevipes and J. luei), arm number (NF = 70 in J. makii, 46 in J. brevipes, and 52 in J. luei), and the number of size groups (two in J. brevipes, and three in J. makii and J. luei). Analyses of sequence variations in the mitochondrial 12S and 16S ribo-some RNA genes supported monophyly of the three

Taiwanese montane species with rather small genetic distances and their sister-group relationships to J. polygonata, leaving J. swinhonis outside. The result strongly suggests that the three montane species have recently originated through a series of specia-tions within Taiwan with driving forces from rapid chromosomal rearrangements. The analyses also strongly suggest an occurrence of initial divergence of J. polygonata in Taiwan and its subsequent, relatively rapid dispersals to most islands of the Ryukyu Archipelago, most likely via repetitive rafting. They further suggest that during the Late Pleistocene glacier period J. swinhonis, a species currently ranging almost throughout the lowland of Taiwan, entirely disappeared in its northern and western parts due to colder and more arid climate there, leaving surviving populations in only a few refuges of the southern and eastern parts. This also explains the absence of this quite adaptive lizard in eastern continent, which is separated from Taiwan only by fairly narrow (< 150 km) and shallow (< 100 m) Taiwan Strait. Current conservation status of the East Asian Japalura populations is also briefly reviewed with a discussion of desirable conservation measures.

Key words: dispersal, isolation, speciation, chromosomes, mitochondrial DNA, conservation.

MOLECULAR PHYLOGENY AND INTRASPECIFIC DIFFERENTIATION OF THE IRANIAN AND CENTRAL ASIAN SPECIES IN THE GENUS TRAPELUS (SAURIA: AGAMIDAE) INFERRED FROM MITOCHONDRIAL DNA SEQUENCES

Eskandar Rastegar-Pouyani l, Nasrullah Rastegar-Pouyani 2, Ulrich Joger 3, and Michael Wink 4

1 Department of Biology, Sabzevar Tarbiat Moalem University PO Box 397 Sabzevar, Iran E-mail: rastegarpouyani45@gmail.com

2 Department of Biology, Faculty of Science, Razi University Kermanshah 67149, Iran

3 State Natural History Museum 10 Pockels Str., Braunschweig 38106, Germany

4 Institute ofPharmacy and Molecular Biotechnology, Department of Biology, University of Heidelberg Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany

The steppe agamas of the genus Trapelus Cu-vier, 1816, are an old clade of agamid lizards with an Afro-Arabian origin. The genus consists of about 14 - 15 species which are distributed from northwestern Africa, along the Saharan border, through the Near East to southwest and central Asia. They

constitute one of the major components of the Iranian Plateau and central Asian fauna and are highly adapted to steppe, semi-deserts and desert environments. To date, published morphological and molecular phylogenetic hypotheses of Trapelus are only partially congruent, and the relationships

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СОВРЕМЕННАЯ ГЕРПЕТОЛОГИЯ 2010 Т. 10, вып. 3/4

DeAgamis2: 2nd INTERNATIONAL SYMPOSIUM ON AGAMID LIZARDS

within the genus are still far from clear. We investigated the phylogenetic relationships and intraspeci-fic differentiation among the Iranian and Central Asian species of these lizards (69 individuals collected from 14 populations of four well-defined species and several unidentified specimens using two mitochondrial gene fragments (ND2 and cyto-chrome b)). The partition-homogeneity tests indicated that the combined dataset was homogeneous, and maximum-parsimony (MP), maximum-likelihood (ML) and Bayesian (BI) analyses were performed on this combined dataset. The trees reconstructed by different methods were generally very similar. Relationships among the examined species and populations were highly resolved. The basal position in the tree was always occupied by

Trapelus ruderatus (= the formerly T. persicus) which in turn formed the sister taxon for populations of T. lessonae. The phylogenetic analysis together with genetic distances among the major clades suggested that, in the Iranian Plateau, T. agilis, genetically, represents a species complex containing at lease three well distinct taxonomic entities at the species level. The analyses also showed that, despite their vast distribution range, the Central Asian populations are genetically very homogenous, just representing a single taxonomic entity (i.e., T. sanguino-lentus).

Key words: Agamidae, Trapelus, T. agilis complex, molecular phylogeny, intraspecific differentiation, mitochondrial DNA, Iranian Plateau, Central Asia.

NOMENCLATURAL DILEMMA OF TRAPELUS RUDERATUS-LESSONAE-PERSICUS (SAURIA: AGAMIDAE): SOLVING THE PUZZLE

Nasrullah Rastegar-Pouyani

Department of Biology, Faculty of Science, Razi University Kermanshah 67149, Iran E-mail: nasrullah.r@gmail.com

Based on extensive study and collecting material in the field and examining the relevant material in the museums and zoological collections, including the type specimens of Trapelus ruderatus ruderatus (Olivier), T. megalonyx Gunther, T. lessonae (De Filippi), T. persicus (Blanford) and T. ruderatus baluchianus (Smith), the taxonomic status of the ground agamids Trapelus ruderatus ruderatus, T persicus and T. lessonae has been re-evaluated.

Based on this study, it was found that the holotype of Trapelus ruderatus ruderatus is a subadult of the conventional T. persicus and that of T. lessonae is a typical form of the conventional T. ruderatus ruderatus. With regards to these re-

markable mis-identifications by the original de-scribers and in order to resolve the taxonomic and nomenclatural status of the three above-mentioned taxa, some major nomenclatural changes are proposed as follows: Since T. lessonae is the oldest available name, it is revived for all populations of the conventional T. ruderatus ruderatus and the specific name «ruderatus» is, in turn, assigned for all populations of the conventional T. persicus (due to priority rule). Therefore, the specific name «per-sicus» comes under the synonymy of «ruderatus» and is no longer available.

Key words: Agamidae, Trapelus, nomencla-tural dilemma, taxonomic re-evaluation.

COBPEMEHHA3 TEPnETO.nOrHtf 2010 T. 10, Bbm. 3/4

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