Geographic variation in the morphology of Macrovipera lebetina (Linnaeus, 1758) (Ophidia: Viperidae) in Iran

Abstract

The Levantine viper, Macrovipera lebetina , has an extensive geographical range being distributed in central Asia and the Middle East. The species exhibits high levels of polymorphism, especially in colouration and pattern. Recent studies revealed significant morphological differences between the two subspecies from northeastern and western portions of Iran. However, considering limited geographic samplings, taxonomic status of Iranian Macrovipera are controversial. In this study, uni- and multivariate statistical techniques were used to analyze geographic variation in 31 morphological characters measured in 117 specimens of Macrovipera lebetina covering its entire range in Iran. Sexual dimorphism was obvious in number of scales across the head and subcaudals. Univariate analyses detected substantial geographic variation in several meristic characters. Pholidosis exhibits a general north-south pattern of variation and most scale counts averaged higher in southern regions. Colouration displayed a pattern of strong clinal variation among three broad areas consisting of the combined western and northwestern, northeastern, and southern highland regions. Also, morphometric characters exhibited a general north-south pattern of geographic variation and some characters averaged lower in southern regions. Populations from the southern regions remained clearly distinct in Principal Component, Cluster and Discriminant analyses. In the light of these differences, it is concluded that the southern Iranian populations should not be identified as belonging to Macrovipera lebetina obtusa (Dwigubsky, 1832), which occurs in northwestern and western regions of the Iranian Plateau.