Acta Medica Mediterranea, 2018, 34: 583 GEOMETRIC MORPHOMETRIC ANALYSIS OF HEAD SHAPE IN A SPOTTED WHIP SNAKE (HEMORRHOIS RAVERGIERI) IN DIFFERENT HABITATS OF IRAN MINOO MOSHTAGHIE1, MOHAMMAD KABOLI2*, MANSOUR SALEHI3 1Department of Environment and Energy, Science and Research Branch, Islamic Azad University, Tehran, Iran - 2Department of Environment, Faculty of Natural Resources, University of Tehran, Iran - 3Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences ABSTRACT Morphological patterns of existing variation and investigative concept related to diversity can be very important in understan- ding the evolution of morphology. It is known that phylogenetic history, size and ecology can all promote the evolution of morpholo- gical variation; however, some methods have been recently developed to analyze these aspects for particular body structures. Spotted whip snake Hemorrhois ravergieri appears to have the widest distribution of the Hemorrhois snake genus, especially in Iran. Morphological difference resulting from habitat can occur in several populations of H. ravergieri. Some studies have studied the relation between morphology and habitat use, revealing that motion is the main facilitator of this evolutionary relationship. Now, we consider intraspecific ecomorphological in three habitat types. Geometric morphometric analyses can provide a more detailed image of head shape in three directions (dorsal, lateral and ventral) on three types of habitat: north-west of Iran, north-east of Iran and central Zagros of Iran. Adult specimens were selected and characteristics of head were analyzed, along with body and head size for understanding the proximate mechanisms, which might be involved. The morphological variation between H. ravergieri indicated that variation in size and head dimensions between species and sexes are highly significant in habitat. Males and females differed in head characters and body size; especially, males were found to exhibit a disproportionate increase in head size and dimensions. H. ravergieri from north-east and central Zagros are smaller, than those living in north-west are. The results revealed that considering the previous findings on the populations, the morphological differences were probably not caused by competition between the popu- lations; instead, these traits could be attributed to the natural selection. Keywords: geometric morphometric, Hemorrhois ravergieri, head shape, habitat. DOI: 10.19193/0393-6384_2018_2s_92 Received November 30, 2017; Accepted January 20, 2018 Introduction Spotted whip snakes belonging to Colubridae family (genus Hemorrhois), have four species, While species identification and their delin- namely Hemorrhois ravergieri, H. nummifer, H. eation should be regarded as one of the most impor- hippocrepis and H. algirus. Although they are non- tant problems that should be taken in to account in venomous snake species, their behaviors are similar the study of taxonomy and evolution, they can be to those of venomous snakes(33,34,39). This genus has a quite necessary in the discovery of life’s diversi- wide species dispersal in different habitats of Asia, ty(38). To find the patterns of variation within and/or southern Europe and northern Africa(35,39). H. between the species, the evolutionary biology ravergieri has the widest distribution range among should be addressed. Some species (especially the genus; smallest size of which is about (50 cm) snake) have a wide variety of morphs in different and the longest one was reported about 159 cm(14). habitats due to the adaptation phenomenon(4). 584 Minoo Moshtaghie, Mohammad Kaboli et Al It is known that each species displays a wide cal characteristics. It should be noted that the main range of shapes in different habitants; consequently, goal in geometric morphometrics is to measure morphological patterns can be employed to deter- morphological similarities and differences; the mine apparent characteristics, as well as other main concern has been solving patterns of biogeo- behavior changes that occur in different ecosys- graphical variation in different phenotypes in the tems. So more complex measurement techniques case of Hemorrhois species in Iran. such as geometrical shape can be employed for the Finally, geometric morphometrics can be purpose of better identification(41). employed in order to conduct a fine-scale analysis It has been shown that various ecological roles of dorsal, lateral and ventral head shape develop- of a structure, in addition to its size, can play a cru- ment; this approach can facilitate the study of dif- cial role in determining the evolution of morpholo- ferent head regions, thereby finding those that are gy. In the case of squamates (including snakes), it particularly modified during ontogeny. has been revealed that the head and cranium shapes can predict such things as the foraging behaviour, Material and methods prey capture, refuge use, defense and aggressive behaviours(4,19,36). For the vast majority of snake Locality and field study species, it has been shown that the head size limits Field samplings were performed during 2015- the maximum prey size. There are also few studies 2016, under the permission, with the reference that have already addressed the form-function rela- number: 29304/95, from the Department of tionship between squamate head morphology and Environment, Iran. Forty nine specimens were col- bite performance(21,32). lected from extensive fields of Iran including (i) In recent years, there have a relatively large north-east of Iran, (ii) north-west of Iran, and (iii): number of functional studies considering geometric central Zagros. Only 34 matures (22 male and 12 morphometric analyses, e.g.,(30). It has been revealed female) specimens, which did not suffer from dam- in the the last decades that the morphometrics could age or head scales deformations, were selected to be improved by methods in which the geometry of be used for photography. shape has been preserved in the analysis of biologi- Statistical analysis cal forms to make use of new image technologies Sex and state of sexual maturity were verified in order to get data and visualize the obtained after dissection(22). After recording the sex and results(1). Some methods have also been developed snout-to-vent length (SVL), the graph paper was set recenetly to illustrate multivariate variations in underneath the heads in order to record scales, and shape that could be simply understood within a photos of the dorsal, lateral and ventral views of the geographic framework(8). head (Figure 1) were taken using a Cannon The pioneering traditional morphometric study Professional camera with 18-megapixel resolution. on the H. ravergieri (in Iran) reported a significant difference in ventral scales between males and females. From another point of view, for the clarifi- cation of species biosystematics, geometric mor- phometric, phylogenetic and molecular studies are recommended, Due to different head shape and col- ors observed between different populations of H. ravergieri in Iran, morphometric studies are unable to distinguish them by morphometric characters(15). Although a large number of the previous stud- ies have been concerned the genetic and phyloge- netic properties of Colubridae family all over the (27) Figure 1: Landmarks positioned on A: dorsal view, B: world , geometric morphometric and genetic ventral view and C: lateral view of head in the H. raver- information is meager regarding the populations of gieri. H. ravergieri, especially those inhabiting in Iran. In this regard, a comparison between H. ravergieri Geometric morphometrics is a well-estab- species in different habitats can be helpful in find- lished technique(10,24,2) that effectively allows non- ing whether or not there are significant morphologi- shape information to remove from geometric struc- Geometric morphometric analysis of head shape in a spotted whip snake... 585 tures(5,13) and has been proved to be more powerful two categories (male and female). In this study, sex- than traditional morphometrics(29). ual categories were statistically different in popula- A geometric morphometric analysis was per- tions. formed using high quality pictures from the dorsal, Specimens were grouped in three geographic lateral and ventral head of 38 specimens. 34 land- samples based on geographic units: (i) north-east of marks in dorsal view, 17 landmarks in lateral view Iran, (ii) north-west of Iran, and (iii): central and 16 landmarks in ventral view (Figures 1a,1b, Zagros. Some biometric variables were tested for and 1c) were digitized for each specimen using homoscedasticity (Levene’s test, P > 0.05). The TpsDig2(30). Since landmark positions can convey SVL and head dimensions seem to be the most important phylogenetic, developmental and func- important variables in the analyses (p= 0.011) tional information, it is very necessary to digitize (Table 1). and analyze landmarks correctly before commenc- Morphometric category mean Standard deviation ing any morphometric study(41). These configura- characters tions were superimposed using a General SVL male 79.50 b 14.08 Procrustes Analysis (GPA) as previously suggested female 84.18 a 6.03 by(31). The measurement errors present in the dataset TL male 22.27 b 4.02 obtained with the above-mentioned experimental design were quantified using a Procrustes ANOVA. female 23.73 a 2.44 After that, a file in tps format was created for all HL male 3.4 0.24 groups studied with tpsUtil(30).