Thursday, November 11, 2010

The Caló den Rafelino Viper


The Blunt-nosed Viper, Macroviper lebetina.
The Oriental Viper complex contains the Desert Viper (Macroviper deserti) from North Africa. The Blunt-nosed Viper (Macroviper lebetina) a widespread North Africa-Middle Eastern species; the Moorish Viper (Macroviper mauritanica), from northwest Africa; the Milos Viper (Macroviper schweitzeri) from the Cyclades Archipelago in the Aegean Sea, as well as Milos Island and its satellites; and probably the Palestine Viper (Macroviper or Viper palestinae) from Israel, Syria, Jordan, and Lebanon; and several fossil forms. Nilson and Andrén (1997) also included the Russel's Vipers (Daboia) in this clade. These snakes tend to be found at low elevations and low latitudes, and prefer hot, dry climates, and they lay eggs (unlike other European and Middle Eastern Vipera). Now, Bailon et al. report the first fossil record of Oriental vipers from the Pliocene of the western Mediterranean.   Two large-sized vertebrae were found in karst deposits on the eastern coast of Mallorca, close to Caló den Rafelino. The centrum length of the trunk vertebra (12.7 mm) represents the largest known specimen of the Oriental viper complex and it suggests a species that reached a body length of about 200 cm. The authors hypothesize that this snake reached Mallorca in the Miocene (5.6-5.32 MYA) during the Messinian Salinity Crisis. At this time sea level dropped about 1500 m establishing a connection between the mainland and the Balearic Islands. Favorable ecological conditions for these snakes most likely existed at this time, including a warm-temperate climate and a relatively dry, open landscape. The authors suggest that because of its large body size; the Caló den Rafelino Viper can be considered one of the largest predators in Mallorca during the Early Pliocene.

Literature
Bailon, S., P. Bover, J. Quintana and J. A. Alcover. 2010.First fossil record of Vipera Laurenti 1768 “Oriental vipers complex” (Serpentes: Viperidae) from the Early Pliocene of the western Mediterranean islands. Comptes Rendus Palevol, 9:147-154.

Nilson, G., and C. Andrén.  1997. Evolution, systematics and biogeography of Paleartic vipers, In: R.S. Thorpe, W. Wüster, A. Malhotra (Eds.), Venomous snakes: ecology, evolution and nakebite. Symposium of the  Zoological Society of London 70:31–42.

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