Biodiversity of the snakes in northern and western mountains of Iran, with special emphasis on biodiversity in colubroids

Snakes are the second most specios group of living reptiles. Colubroidea, with more than 2500 species, is one of the most conspicuous radiations of terrestrial vertebrates. Recent studies show that globally 12% of the snake species are estimated to be threatened with extinction. This estimation increases when including the cryptic species (discrete species that are difficult, or sometimes impossible, to distinguish morphologically and thus have been incorrectly classified as a single taxon) too. It is possible that some of the snakes biodiversity may get extinct even before a proper identification. In the developing countries like Iran this situation is even more serious. The country of Iran has the greatest faunal and floral diversity of the southern and arid parts of the Palaearctic realm, including a considerable diversity in the snakes. But there is insufficient data on the biodiversity of snakes in Iran and limited data about cryptic species of snakes in the country. In this PhD study, I have aimed to investigate the taxonomy of selected species of Iranian snakes, inhabiting the northern and western mountains of Iran. Relevant taxa were detected based on a review performed on the available taxonomic data on snakes of Iran. Snake taxa with a wide distribution range that reflect complexity of adaptations to different ecosystems or have great matter of taxonomic confusion, including the Eirenis medus species complex, the Eirenis persicus species complex, the Eirenis punctatolineatus, the Montivipera raddei species complex, and Natrix tessellata, have been selected for this study. Samplings were done in the northern and western mountains of Iran between 2008 and 2011. Patterns of morphological variation and its relevance for taxonomical interpretations of the Montivipera raddei species complex, as well as the taxonomy of Natrix tessellata, Eirenis punctatolineatus and Eirenis medus species complex, were investigated using a principal component analysis (PCA) and a multivariate analysis of variance (MANOVA) on metric and meristic data of the specimens. Taxonomy of the Eirenis persicus species complex was studied using both traditional biometry and geometric morphometry on landmark data of the dorsal head scales. Two mitochondrial genes, 16S rRNA and cytochrome b, and one nuclear gene, c-mos, were sequenced and then a concatenated data set of these was analyzed to generate a Bayesian inference of phylogeny. The morphological analysis on the Montivipera raddei species complex revealed that a couple of specimens of the genus Montivipera, originating from the central Zagros mountain range, 216 is representing an unknown species. This species, named Montivipera kuhrangica Rajabizadeh, Nilson and Kami, 2011, has a higher count of head scales than other closely related species, including higher a number of intercanthal, supralabial scales and scales between the last supralabials. The field data indicate that in the Montivipera raddei species complex, there is a correlation between the dorsal color pattern variation and the environmental factors of the habitat, including vegetation and substrate color. In order to study geographic variation of Natrix tessellata in Iran, a total of 66 specimens, including 39 males and 27 females, were examined. The analysis on both sexes separately revealed that the males from the Fars province (southern Zagros) are significantly different from all other dice snakes in Iran, in the tail length, head length, head width and number of ventral scales. Further studies are needed to resolve the taxonomic problem of the southern Zagros populations of Natrix tessellata. The analysis on 23 males and 21 females of Eirenis punctatolineatus indicates that the southern Zagros populations differ significantly from the rest of the populations in tail length and number of subcaudal scales, number of preventral scales, number of scales bordering parietals and shape of the dorsal color pattern in both sexes. A subspecific subdivision is suggested for the northern and southern populations. As a new combination, Eirenis punctatolineatus condone (Boulenger, 1920), is proposed for the southern populations. Analysis on the three populations of Eirenis medus species complex from Turkmenistan and northern and western mountains of Iran, revealed a couple of specimens from Kerman province in southern Zagros that differs from known populations of Eirenis medus in their morphometric and meristic characters. Compared with Eirenis medus, this new species, named Eirenis kermanensis Rajabizadeh, Schmidtler, Orlov and Soleimani, 2012, has a higher number of subcaudals and a higher ratio of tail length over total length. Also in Eirenis kermanensis, the loreal scale is deeper than long, while in Eirenis medus the loreal is longer than deep. In studying the taxonomy of the Eirenis persicus species complex, the biometric data from 23 males and 17 females revealed that the populations of Eirenis persicus in the western mountains of Iran and Turkey are significantly different from the populations in eastern Iran, Turkmenistan and Pakistan. This significant divergence was confirmed by geometric morphometric and molecular analyses too. Both molecular and morphological analyses showed that specimens of the Eirenis persicus species complex that belong to the nigrofasciatus morph, are closely related to the eastern populations of the Eirenis persicus species complex. Within-group PCA revealed that Eirenis persicus populations of Iran and Turkey are morphologically different from each other at a subspecific level. This result was confirmed by molecular data as well. Studies on the genus Eirenis revealed the occurrence of cryptic biodiversity in these snakes. During the warming periods of the Pleistocene climatic oscillations, the suitable habitat of mountain dwelling snakes shifted to higher altitudes in the mountain. Subsequently, climatic cooling shifted the range of these habitats back to lower altitudes. These altitude shift of the habitat during the Pleistocene climatic oscillations induced the isolation and speciation in the examined snake species throughout the northern and western mountains of Iran. The present study on the selected species of the genera Eirenis, Natrix and Montivipera confirmed that the current knowledge on Iranian snake taxonomy is limited, and undescribed species remain to be discovered. This limited knowledge is to be understood due to the substantial snake biodiversity in Iran (related to its diversity of ecosystems) and lack of in-depth taxonomic studies on snake biodiversity. As such, although most of the results from this study are new related to our understanding of snake biodiversity in Iran, they still cover only a few species of this Iranian diversity, of which a lot remains to be properly assessed

Molecular systematics of the genus Pseudocerastes (Ophidia: Viperidae) based on the mitochondrial cytochrome b gene

The false horned vipers of the genus Pseudocerastes consist of 3 species; all have been recorded in Iran. These include Pseudocerastes persicus, P. fieldi, and P. urarachnoides. Morphologically, the taxonomic border between P. fieldi and P. persicus is not as clear as that between P. urarachnoides and P. persicus or P. fieldi. Regarding the weak diagnostic characters differentiating P. fieldi from P. persicus and very robust characters separating P. urarachnoides from both, there may arise some uncertainty in the exact taxonomic status of P. urarachnoides and whether it should remain at the current specific level or be elevated to a distinct genus. Based on our sequence data from the mitochondrial cytochrome b gene, the taxonomic status of the 3 false horned vipers is confirmed. Although P. fieldi has equal genetic distance from P. persicus and P. urarachnoides, the spider-tailed viper is more closely related to P. persicus than P. fieldi. There are also some subdivisions among the populations of P. persicus in Iran

Interspecific variation within the genus Ophiomorus DUMÉRIL & BIBRON, 1839 (Sauria: Scincidae) in Iran based on morphological characters

Many studies conducted on range of animals showed that morphology is related to habitat. In the present study, we aimed to examine the morphological characteristics of species assigned to the genus Ophiomorus in Iran. Seventy-one specimens from throughout the range of distribution in the central plateau of Iran were investigated. Eleven morphometric and four meristic variables were analyzed independently. Multivariate analyses were performed using canonical variate analysis (CVA) and principal component analysis (PCA). The results showed that there is significant morphological differentiation between three species groups brevipes, tridactylus, and punctatissimus in this genus in relation to habitat choice. ANOVA results showed that 14 morphological characters (SVL, HL, HW, HH, SL, LF, LA, LFL, LFH, LHF, NSL, NDSB, NMC, and NIL; 10 metric and four Meristic) were significantly different among all Ophiomorus species, which based on this, TL did not show a significant difference among species. Finally, we assigned three species groups based on limb reduction (especially fingers), and habitat surface (comparison based on habitat observations) for all Ophiomorus species in Iran. In addition, using newly applied morphological characteristics we proposed an updated identification key for the genus

A new species of Acanthodactylus Fitzinger 1834 (Sauria: Lacertidae) from southern Iran

A new and distinctive species of lacertid genus Acanthodactylus Fitzinger, 1834 is described from 7 km east of Khamir Port, Hormozgan Province, southern Iran at an elevation of 30-40m above sea level (asl). Analyses of morphological characters and the comparison with other formerly known species of this genus have proven the status of this taxon as a new, distinct species. Combinations of scalation characters and distinct morphology, coloration and habitat peculiarities in calcareous mountains distinguish Acanthodactylus khamirensis sp. nov from all remaining species of the genus in the area. In order to show the validity of the new species, we carried out a comparative statistical analysis using 13 metric and six meristic morphological characters on all of the neighboring congeners of the new species using descriptive (one-way ANOVA) as well as multivariate analyses (PCA and DFA). The results confirm the specific status of the new taxon. Detailed information and an updated identification key for the genus Acanthodactylus in Iran are presented

Taxonomic status of Tropiocolotes cf. steudneri with a description of a new species of Tropiocolotes (Reptilia: Squamata: Gekkonidae) in southern Iran

Rajabizadeh, Mahdi, Faizi, Hiva, Anderson, Steven C., Zarrintab, Mohammad, Nazarov, Roman (2018): Taxonomic status of Tropiocolotes cf. steudneri with a description of a new species of Tropiocolotes (Reptilia: Squamata: Gekkonidae) in southern Iran. Zootaxa 4388 (2): 283-291, DOI: https://doi.org/10.11646/zootaxa.4388.2.1

Tooth-shape adaptations in aglyphous colubrid snakes inferred from three-dimensional geometric morphometrics and finite element analysis

To date there are few quantitative studies investigating the evolution of tooth shape and function in aglyphous snakes in relation to diet. A considerable evolutionary decrease in body size is observed in whip snakes of the genus Dolichophis and their sister-group Eirenis. This was coupled with a considerable shift in diet from a regime consisting mainly of prey with endoskeleton to prey bearing a hard exoskeleton. Three-dimensional (3D) geometric morphometrics revealed that the maxillary and palatine teeth of E. persicus are blunt and conical in shape, while the same teeth are sharp and elongated in E. punctatolineatus and D. schmidti. Blunt and conically shaped teeth, as observed in E. persicus, seem to be more adapted for biting hard-bodied, arthropod prey. In contrast, the sharp and elongated teeth in Dolichophis and E. punctatolineatus, are likely specialized for puncturing prey with an endoskeleton. The results of a finite element analysis confirms that during the biting of a hard-bodied prey, the generated stresses in E. persicus teeth are well below the von Mises yield criterion, while in D. schmidti the value is roughly two to three times higher, indicating that E. persicus teeth are better suited for biting hard-bodied prey such as arthropods

Taxonomy, distribution and geographic variation of Eirenis punctatolineatus (Boettger, 1892) (Reptilia: Colubridae)

Distribution and geographic variation in Eirenis punctatolineatus are studied in the whole distribution range of the species. The results show that the species is distributed from eastern central Turkey in the west to east up to northern Khorasan mountains in Iran and from central Armenia in the north to the south up to the adjacency of the seashores of the Persian Gulf. An univariate analysis shows that there is possibly a clinal variation in two morphometric and one meristic characters through the latitudes. Percent ratio of tail length on total length and number of Subcaudal scales increase from north to south and conversely, percent ratio of head length to total length decrease. A subsequent multivariate analysis revealed that populations of Turkey, Transcaucasia and northwestern Iran, referred to as northern populations of Eirenis punctatolineatus, and populations of the southern Zagros Mountains and adjacent areas, referred to as southern populations of Eirenis punctatolineatus are clearly different morphologically, but intermix in an intermediate area. A subspecific subdivision is suggested for the northern and southern populations. As a new combination, Eirenis punctatolineatus condoni (Boulenger, 1920), is proposed for the southern populations