Revision of the African caecilian genus Schistometopum Parker (Amphibia: Gymnophiona: Caeciliidae)
Year: 1998
Type: article
Abstract: We revised African caecilians of the cacciliid genus Sclzistornetopum Parker based on univariate and multivariate analyses of morphometric characters and coloration. S. brevzrostrr (Peters) and S. cpl~eleTaylor, arcjunior synonyms of S. thvmense (Barboza du Bocage), and S. garzonhqdti Taylor and Salvador is a junior synonym of Geotrypetes srraphini (A. Durniril). The two valid species oS Schistometopum occur on opposite sides of the African continent: S. grrgorii (Boulengcr) in coastal Kenya and Tanzania, and S. thomense on S5o Tom6 island in the Gulf of Guinea. Two records for S. thomenseon Principe Island and in the Ruwenzori region of central, equatorial MI-ica arc problematic and require verisication. Geographic variation in color and morphometric characters of S. thomense is pronounced and is remarkable considering the small range ofthis species on an island with seemingly uniforrn habitat. The discovery of pronounced, clinal, microgeographic variation in S. thomense and the erroneous taxonomic concl~~sions derived from it by Taylor is viewed as a strong argument against the trend to elevate "diagnosable" allopatric populations to species status without careful study both in the Geld and in the laboratory. Significant sexual dimorphism in head size is documented for both species oS Schistometopum, with males having the larger heads in both cases. This same pattern of' sexual dimorphism in head size is known for other caecilian species. Sexual dimorphism in head size may result from selection for sexual resource partitioning or for male combat advantage or both. Scarring and fresh bite marks on individuals from both field and laboratory populations suggest that combat may be part of the sociobiology of S. thomense, but the context of this aggression is unknown. S. thom~n,se is abundant in disturbed habitats and does not appear to be threatened with extinction. S. gregoriiwas also abundant in anthropogenic habitats in 1934, but the species has not sincc been reported.
DOI: 10.7274/32351010
Authors: Ronald A Nussbaum, Michael Pfrender
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W198999683