XENODERMIDAE Gray, 1849

Lapparent, France de, Bailon, Salvador, Augé, Marc Louis & Rage, Jean-Claude, 2020, Amphibians and reptiles from the Neogene of Afghanistan, Geodiversitas 42 (22), pp. 409-426 : 422

Family XENODERMIDAE Gray, 1849

or ELAPIDAE Boie, 1827

Genus Xenodermus Reinhardt, 1836 or Bungarus Daudin, 1803

Sp. indet. ( Figs 6 ; 7 )

LOCALITY AND AGE. — Sherullah 9, Khordkabul basin, Afghanistan, late Miocene, late Vallesian-basal Turolian transition, MN10/11.

MATERIAL EXAMINED. — Two incomplete vertebrae (AFG 1672, AFG 1673)

DESCRIPTION

These vertebrae are poorly preserved ( Figs 6 ; 7 ). They show a well-marked abrasion with rounded and polished surfaces affecting all vertebral structures: zygapophysis, neural spine and hypapophysis, most likely as a consequence of a water transport. These vertebrae display the bases of lateral laminae. These laminae originate from the interzygapophyseal ridges and anterolateral borders of the postzygapophyses. They extended horizontally; unfortunately, their shape and extent are unknown. The laminae do not contact the prezygapophyses. The vertebrae are rather depressed. The centrum seems to have a very worn hypapophysis.

COMMENTS

Such lateral laminae are present in rare snakes; among colubroids they occur only in a few colubrid genera (e.g. in the African genus Mehelya and some American dipsadids ( Bogert 1964; Hoffstetter & Gasc 1969; Sánchez-Martinez 2011) and in certain species of the elapid Bungarus ( Hoffstetter 1939; Slowinski 1994). Within Asian colubrids, only Xenodermus (now in Xenodermatidae a basal caenophidian Family placed ouside Colubridae [e.g. Vidal et al. 2007; Zaher et al. 2009; Pyron et al. 2011]) has vertebrae similar to those from Sherullah ( Bogert 1964). On the basis of the two available specimens, referral to either Xenodermus or Bungarus is difficult. However, the Sherullah vertebrae are depressed and the posterior median notch of the neural arch is well pronounced, which is more reminiscent of Bungarus . As a result, this snake might be referred to either Xenodermus ( Colubridae s.l.) or Bungarus (Elapidae) .

A Xenodermus -like snake was reported from the early (or middle?) Miocene of Thailand ( Rage & Ginsburg 1997), however, this material was not accompanied by any kind of figure. An indeterminate species of Bungarus was reported from the late Miocene of Pakistan by Head (2005); furthermore, a vertebra from the late Pleistocene-Holocene of Kurnool Cave, India, attributed to Serpentes indeterminate by Patnaik et al. (2008) is clearly a Bungarus vertebra. Today, both genera are restricted to Asia ( Xenodermus in southeastern Asia, Bungarus in Southern Asia).

Figures

FIG. 6. — Xenodermidae (Xenodermus) or Elapidae (Bungarus), Sherullah, late Miocene, photos:A, B, C, trunk vertebra AFG 1672, dorsal,ventral and right lateral views; D, trunk vertebra AFG 1673, dorsal view. Scale bar: 2 mm.

FIG. 7. — Xenodermidae (Xenodermus) or Elapidae (Bungarus), Sherullah, late Miocene, trunk vertebra, AFG 1672, drawings: A, B, dorsal and anterior views. Scale bar: 3 mm.