Comparison of scale anomalies in populations of northern viper Vipera berus from habitats differing in size and degree of fragmentation

https//doi.org/10.33256/hb171.2024
AUTHORS BRISTOL RIGBY; RICHARD A. GRIFFITHS; NICK DOBBS
ABSTRACT Northern vipers Vipera berus are declining; increasingly confined to fragmented; isolated populations in England. Scale anomalies that occur during development can potentially be related to environmental stressors. Using photographs of the dorsal view of viper heads; we compared levels of head scale fragmentation; asymmetry between four populations to identify the extent of anomalies. Although all populations had vipers that displayed scale fragmentation; asymmetry; the incidence of such anomalies was lowest at Fackenden Down which supports the largest population; is probably the least isolated. Two populations that displayed particularly high levels of scale anomalies – Talbot Heath; Turbary Common – are isolated; surrounded by urban; suburban development. Supraocular; intercanthal scales showed a higher incidence of fragmentation; asymmetry than did apical scales; and there was a general tendency for the vipers with scale fragmentation to also display asymmetry. We speculate that the relatively high incidence of scale anomalies in small; isolated populations may be a result of environmental or genetic pressures; that head scale fragmentation; asymmetry may provide an early indication of such stressors.

The Herpetological Bulletin is a quarterly publication in English. It includes full-length papers, natural history notes, book reviews, and other items of general herpetological interest. Emphasis is placed on natural history and conservation as well as captive care that includes breeding, husbandry, veterinary, and behavioural aspects.

pdf 04. Comparison of scale anomalies in populations of northern viper Vipera berus from habitats differing in size and degree of fragmentation

55 downloads

Open Access

Download (pdf, 805 KB)

https://doi.org/10.33256/hb171.2024

AUTHORS: BRISTOL RIGBY, RICHARD A. GRIFFITHS & NICK DOBBS

ABSTRACT: Northern vipers Vipera berus are declining and increasingly confined to fragmented and isolated populations in England. Scale anomalies that occur during development can potentially be related to environmental stressors. Using photographs of the dorsal view of viper heads, we compared levels of head scale fragmentation and asymmetry between four populations to identify the extent of anomalies. Although all populations had vipers that displayed scale fragmentation and asymmetry, the incidence of such anomalies was lowest at Fackenden Down which supports the largest population and is probably the least isolated. Two populations that displayed particularly high levels of scale anomalies – Talbot Heath and Turbary Common – are isolated and surrounded by urban and suburban development. Supraocular and intercanthal scales showed a higher incidence of fragmentation and asymmetry than did apical scales, and there was a general tendency for the vipers with scale fragmentation to also display asymmetry. We speculate that the relatively high incidence of scale anomalies in small, isolated populations may be a result of environmental or genetic pressures and that head scale fragmentation and asymmetry may provide an early indication of such stressors.