Vipera Laurenti, 1768

Rage, Jean-Claude & Bailon, Salvador, 2005, Amphibians and squamate reptiles from the late early Miocene (MN 4) of Béon 1 (Montréal-du-Gers, southwestern France), Geodiversitas 27 (3), pp. 413-441 : 434-435

Genus Vipera Laurenti, 1768 (“oriental complex”) or Daboia Gray, 1842

“ Vipera (Oriental viper) – J.-C. Rage (unpublished)” – Szyndlar & Rage 2002: 438.

MATERIAL EXAMINED. — 141 trunk vertebrae (Béon 2004 LT 83-86; Béon 93 E3 SN 6; Béon 98 déblais SN 2; Béon 98 E3 3043; Béon 98 F1 3074).

DESCRIPTION

The size of this fossil corresponds to that of vipers referred to the “oriental complex” of Vipera or to Daboia ( Szyndlar & Rage 1999, 2002). The length of the centrum of the largest specimen reaches 8.6 mm. Moreover, as is typical for these large vipers the neural arch is strongly depressed, nearly flat. In several vertebrae from Béon 1, the neural arch is thickened above the postzygapophyseal facets; this “epizygapophyseal thickening” sometimes forms an epizygapophyseal spine. This character is not frequent in large vipers from the Neogene of Europe. The neural spine is preserved on some vertebrae; it is very high in the anterior and mid-trunk regions, but that of posterior trunk vertebrae is unknown.

COMMENTS

In Europe, large vipers have been reported from the late early Miocene (MN 4) to the latest Pliocene (MN 17) ( Szyndlar & Rage 2002) and from the Pleistocene ( Schneider 1975; Szyndlar 1991b). Szyndlar (1987) referred all the large vipers from the European Neogene to the informal subdivision “oriental vipers” of the genus Vipera ; this complex also includes extant species. Subsequently, Szyndlar & Rage (1999, 2002) removed the genus Daboia from this assemblage. Daboia is mainly distinguished from Vipera of the oriental complex on the basis of skull bones. But vertebrae may be also identified: in Daboia the neural spine is higher than in oriental vipers; however, this difference is not always marked in fossils. For example, Szyndlar & Rage (1999) were unable to assign a large viper from Vieux- Collonges (MN 4/5, France) to either Daboia or the oriental complex of Vipera although some vertebrae preserve neural spines. At Béon 1, the neural spine of the most anterior vertebrae (transition between anterior and mid-trunk regions) is very high and reminiscent of Daboia . But, in the mid-trunk region, the neural spine does not appear to be higher than in species of the oriental complex. Consequently, this large viper from Béon 1 cannot be confidently referred to either Daboia or the oriental complex of Vipera , which is reminiscent of the large viper from Vieux- Collonges. However, the form from Vieux- Collonges differs slightly from the viper from Béon 1. At Vieux-Collonges, all mid-trunk vertebrae lack an epizygapophyseal spine and, in large vertebrae, the anterior edge of the zygosphene is straight at Vieux-Collonges while it is generally concave at Béon 1. In addition, the specimens from Vieux-Collonges are larger (the centrum reaches 10.2 mm) than those from Béon 1.

The oriental complex includes six living species of Vipera . The range of this assemblage extends from northwestern Africa and southeastern Europe to India. Szyndlar & Rage (2002) assigned six or seven extinct species to the oriental complex. They inhabited Europe from Portugal to Georgia; to the north, they reached north central France, Bohemia, and east central Ukraine; they are known from the early Miocene (MN 4) to the late Pliocene (MN 17). Indeterminate vipers of the oriental complex were reported from Africa: latest Pliocene and Pliocene/Pleistocene transition of Morocco ( Bailon 2000; Szyndlar & Rage 2002) and perhaps early Miocene (Burdigalian) of Namibia ( Rage 2003a). A single living species belongs to Daboia ( D. russelii ); it occupies southern Asia from Pakistan to Indonesia ( Golay et al. 1993). Only one extinct species is assigned to Daboia : D. maxima ( Szyndlar, 1988) from the Pliocene (MN 15) of Spain ( Szyndlar 1988). Daboia was perhaps also present in the early/middle Miocene of Vieux-Collonges (MN 4/5, France) and the early Miocene of Namibia ( Rage 2003a).

Consequently, whatever its exact genus reference, the large viper from Béon 1 is one of the earliest representative of either Daboia or the oriental complex of Vipera .