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1 October 2016 Skull Size and Shape Variation in Psammomys spp. (Rodentia, Gerbillinae) from Tunisia, with Emphasis on the Impact of Allometric Variation on Species Recognition
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Abstract

In Tunisia both Psammomys obesus and P. vexillaris are found. These taxa have been the subject of taxonomic controversy for some time, due to variability in the classical morphological characters used for taxonomic recognition. In this study we investigated skull size and shape variation in the genus Psammomys by using geometric morphometrics to evaluate the extent of intra- and interspecific shape variation and explicitly tested for the impact of allometric shape variation on species discrimination. Eleven populations of the two species from 10 localities in Tunisia were studied. Statistical analyses of size and shape showed large size variation within P. obesus, but no shape differences were revealed among populations of this species. Interspecific analysis revealed that P. vexillaris had the smallest skull. Principal component analysis and Procrustes distances showed good discrimination between the two species after removal of the allometric component of shape variation. The results obtained show that allometric-related shape variation could mask discrimination between the two Psammomys species. This finding might explain the uncertainty in classification of these species in the past. The interspecific allometric-free phenotypic differences observed may be associated with adaptive processes linked to the different environmental and trophic preferences of the two species.

© Zoological Society of Southern Africa
Hanene Khemiri, Paolo Colangelo, M'barek Chétoui, and Saïd Nouira "Skull Size and Shape Variation in Psammomys spp. (Rodentia, Gerbillinae) from Tunisia, with Emphasis on the Impact of Allometric Variation on Species Recognition," African Zoology 51(3), (1 October 2016). https://doi.org/10.1080/15627020.2016.1233828
Received: 27 February 2016; Accepted: 1 September 2016; Published: 1 October 2016
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