Cerastes

Stümpel, Nikolaus & Joger, Ulrich, 2009, Recent advances in phylogeny and taxonomy of Near and Middle Eastern Vipers – an update, ZooKeys 31 (3), pp. 179-191 : 186-187

Cerastes and Echis

These two genera have been united in a monophyletic group based on the shared character of serrated lateral scales which they use for producing a warning sound like a rattle-snake (Groombridge 1986). It is considered an adaptation to desert conditions. However, as the harmless colubrid Dasypeltis and some species of African bushvipers (genus Atheris ) possess the same type of serrated scales, a convergent development is possible ( Joger & Courage 1999). A new phylogenetic analysis (Pook et al., in press) confirms the monophyly of Echis and Cerastes .

Cerastes , the Horned vipers, do not always bear horns on top of their supraorbital scales. There is a hornless species, Cerastes vipera , which is found in sand dune areas in North Africa, Egypt and Israel / Palestine. Cerastes cerastes , a less specialized species, maybe horned or hornless ( Figs 8 , 9 ) and occupies, in a number of subspecies, desert and semi-desert areas in North Africa and western Arabia ( Werner et al. 1991, Werner and Sivan 1992). Th e typical desert snake of most of Arabia and Khuzistan province ( Iran) is Cerastes gasperettii Leviton & Anderson, 1967 (Gasperetti 1980) , the sister species of C. cerastes , but which nearly always bears horns.

Echis , the Saw-scaled vipers, are found in a very large area from West Africa to India, including most of the Middle East countries. Th eir systematics and taxonomy have been a discussed for decades. Klemmer (1963) recognized only two species: Echis carinatus in most of the range and E. coloratus in Arabia. Joger (1984, 1987 ) added E. pyramidum for southwestern Arabia. Cherlin (1990) described a number of new species and subspecies and increased the total number of Echis species significantly. A new species within the E. coloratus group was described by Babocsay (2004). Pook et al. (in press), using molecular genetic methods, have now clarified the complicated situation. On the basis of their results and additional data, we recognize the following six species in the Near and Middle East:

Echis carinatus group (Asian group):

E. ( carinatus ) sochureki ( Oman, UAE, Iran, Central Asia, Afghanistan, Pakistan)

Echis coloratus group (Arabian group):

E. coloratus ( Egypt, Arabian Peninsula)

E. omanensis ( Oman, UAE)

Echis pyramidum group (one of two African groups):

E. pyramidum ( Egypt, Sudan, East Africa)

E. khosatzkii (western Oman, Yemen)

E. sp. ( cf. borkini ) ( Yemen, SW Saudi Arabia)

E. borkini was originally described as a subspecies of the East African E. varia by Cherlin (1990). As we did not find a close phylogenetic relationship between Echis populations from Yemen and Ethiopia, we consider borkini a separate species.

There is a strong zoogeographical division in Arabian Echis , E. sochureki and E. omanensis being found in the eastern part of the peninsula only, whereas southwestern Arabia (including Dhofar province, Oman) is inhabited by E. coloratus , E. khosatzkii and E. cf. borkini (see also Joger 1987).

As Echis bites frequently cause death and successful bite treatment depends on choosing a species-specific antivenom (if available), it is of great importance to know which species of Echis occur in which area. Th ere is still need for additional research in this genus. It is also time for an effort to study the venom of species like E. khosatzkii and E. cf borkini , and start production of antivenom against their bites.

Figures

Figure 8. Cerastes gasperettii (horned)

Figure 9. Cerastes gasperettii (hornless)