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Evolutionary divergency of giant tortoises in Gal?pagos

Biological Journal of the Linnean Society

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Abstract

The giant tortoises in the Galapagos Archipelago diverge considerably in size, and in shape and other carapace characteristics. The saddleback morphotype is known only from insular faunas lacking large terrestrial predators (i.e. Galapagos and Mauritius) and in Galapagos is associated with xeric habitats where vertical feeding range and vertical reach in agonistic encounters are adaptive. The large domed morphotype is associated with relatively cool, mesic habitats where intraspecific competition for food and other resources may be less intense than in xeric habitats. Other external characteristics that differ between tortoise populations are also correlated with ecological variation. Tortoises have radiated into a mosaic of ecological conditions in the Galapagos but critical data are lacking on the role of genetic and environmental controls on phenotypic variation. Morphological divergence in tortoises is potentially a better indicator of present ecological conditions than of evolutionary relationships.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Evolutionary divergency of giant tortoises in Gal?pagos
Series title:
Biological Journal of the Linnean Society
Volume
21
Issue:
1-2
Year Published:
1984
Language:
English
Publisher:
U.S. Fish and Wildlife Service
Contributing office(s):
Patuxent Wildlife Research Center
Description:
165-176
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Biological Journal of the Linnean Society
First page:
165
Last page:
176