The shrew tenrecs of Madagascar : systematic revision and Holocene distribution of Microgale (Tenrecidae, Insectivora). American Museum novitates ; no. 2889

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Date

1987

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Publisher

New York, N.Y. : American Museum of Natural History

DOI

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Abstract

"The shrew tenrecs of Madagascar - Microgale and the allied nominal genera Leptogale, Paramicrogale, and Nesogale - have never been formally revised. Examination of all relevant type material reveals that only 10 of the 22 nominal species-group names of shrew tenrecs deserve recognition. The large number of synonyms is principally due to authors' repeated commission of two substantial errors: (1) failing to recognize the juvenile status of many 'adult' specimens used as holotypes, and (2) failing to appreciate the marked degree of within-group variation in these insectivores. Analysis of a range of metric and nonmetric traits further reveals that there are only three or four distinctively different morphological clusters of shrew tenrecs in the modern fauna, and that all species clusters can be comfortably accommodated in one genus, Microgale. Illustrations of deciduous and adult dentitions and a key to recognized and reorganized specie are provided. Revision permits, for the first time, an approximate idea of the true ranges and habitat preferences of shrew tenrec species. Although the majority of species appear to be restricted to the comparatively moist and equable conditions of the eastern rain forest, several species occur in forest islands and other favorable habitat in the eastern part of the highlands, and two (M. pusilla and brevicaudata) have occupied the dry, highly seasonal western side of the island in recent times. Despite its morphological primitiveness, Microgale can be aptly described as adaptively resilient. Colonization of the highlands and the far west presumably occurred by pioneering groups moving out from the eastern forest belt during times of climatic amelioration and forest expansion; isolation of these groups would have occurred when conditions deteriorated in the center. Emigration events could have occurred repeatedly, although the nature of Malagasy environmental dynamics is not known in detail before about 10,000 BP, and not at all before 35,000 BP. In any event, it is no longer necessary to believe that all known disjunctions in the species ranges of Malagasy vertebrates occurred simultaneously about 2000 years ago, when the island was first settled by humans"--P. [1]-2.

Description

45 p. : ill., map ; 26 cm.
Includes bibliographical references (p. 43-45).

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