The lacunolabial scale is a large
scale that forms in some
crotaline snakes (pitvipers) when the
prelacunal scale fuses with the second (rarely the third)
supralabial scale. In such cases, it is often said that "the second labial enters the pit".
[Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. 2 volumes. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. .] Some pitvipers, such as
Bothrops alternatus
''Bothrops alternatus'', known by the common names crossed pit viper''U.S. Navy. 1991. ''Poisonous Snakes of the World''. US Govt. New York: Dover Publications Inc. 203 pp. .'', yarará grande, and urutu,Campbell JA, Lamar WW. 2004. ''The Venomo ...
,
Bothrops erythromelas,
Bothrops itapetiningae and
Bothrops neuwiedi, have a divided lacunolabial scale.
References
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Snake scales