Why cordylid lizards are black at the south-western tip of Africa

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dc.contributor.authorJanse van Rensburg, D. A.
dc.contributor.authorMouton, P. le F. N.
dc.contributor.authorVan Niekerk, Adriaan
dc.contributor.other0000-0002-5631-0206
dc.date.accessioned2011-09-01T13:15:18Z
dc.date.issued2009-03
dc.descriptionThe original publication is available at http://onlinelibrary.wiley.com/en_ZA
dc.description.abstractThere is a high incidence of melanism among the cordylid lizards of Africa and it was suggested that melanism has a thermoregulatory function in these species. One prediction of the thermal melanism hypothesis would be that melanistic cordylid species would be restricted to cool environments. The aim of our study was to determine the climatic conditions with which melanistic cordylids are currently associated.Distributional data for the eight melanistic cordylid taxa occurring at the south-western tip of Africa were obtained from the CapeNature State of Biodiversity database. Using GIS and principal component analyses, the climatic variables best describing the geographical distribution of melanistic cordylids were investigated. We found that several melanistic cordylid populations show a distinct association with a high incidence of fog and cloud cover, underscoring the thermal melanism hypothesis. Several other populations, however, do not show such an association. We conclude that some species, such as Pseudocordylus capensis, have a morphology that provides them with great flexibility in habitat use, allowing them to overcome the constraints of melanism in warm environments. The available information suggests that melanism in cordylids evolved during the Miocene in response to the development of the cold Benguela Current along the west coast of Africa.We also conclude that viviparity, a sit-and-wait foraging strategy and a rockdwelling lifestyle would have preadapted cordylids for survival in cool conditions brought about by the development of the cold Benguela Current. These conditions would have been unfavourable for oviparous, active-foraging lizards. The cooccurrence ofmelanistic lizards andmelanistic molluscs at the Landdroskop locality casts some doubt on improved heating rates as the only explanation for melanism in cordylids, because molluscs are not heliothermic baskers.en_ZA
dc.description.versionPublishers' Versionen_ZA
dc.embargo.lift2025-12-31
dc.embargo.terms2025-12-31en_ZA
dc.format.extentp. 333-341 : maps
dc.identifier.citationJanse Van Rensberg, D. A., Mouton, P. le F. N. & Van Niekerk, A. 2009. Why cordylid lizards are blackat the south-western tip of Africa. Journal of Zoology, 278, 333-341, http://onlinelibrary.wiley.com/en_ZA
dc.identifier.issn0952-8369 (print)
dc.identifier.issn1469-7998 (online)
dc.identifier.urihttp://hdl.handle.net/10019.1/16345
dc.language.isoen_ZAen_ZA
dc.publisherBlackwell Publishing Ltden_ZA
dc.rights.holderBlackwell Publishing Ltden_ZA
dc.subjectCordylid lizards -- Africa, Southwesternen_ZA
dc.subjectCordylids -- Melanism -- Effect of climate on -- Africa, Southwesternen_ZA
dc.subjectThermoregulationen_ZA
dc.subjectVivipartityen_ZA
dc.titleWhy cordylid lizards are black at the south-western tip of Africaen_ZA
dc.typeArticleen_ZA
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