Chapter

The Octodontidae Revisited

Milton H. Gallardo, Ricardo A. Ojeda, Claudio A. González and Carolina A. Ríos

in The Quintessential Naturalist

Published by University of California Press

Published in print July 2007 | ISBN: 9780520098596
Published online March 2012 | e-ISBN: 9780520916159 | DOI: http://dx.doi.org/10.1525/california/9780520098596.003.0019
The Octodontidae Revisited

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This chapter observes that the monophyletic and depauperate assemblage of South American octodontid rodents has experienced an extensive adaptive radiation from above-ground dwellers to subterranean, saxicolous, and gerbil-like deserticolous life forms. It notes that complex and saltational chromosomal repatterning is a hallmark of octodontid evolution. The chapter further notes that recent molecular evidence links these chromosome dynamics with quantum genome size shifts, and probably with reticulate evolution via introgressive hybridization in the desert dwellers Tympanoctomys barrerae and Pipanacoctomys aureus. It theorizes that genome duplication represents a novel mechanism of evolution in mammals and its adaptive role is reflected in the ability of deserticolous species to colonize the extreme environment of salt flats. The chapter observes that unique to Tympanoctomys is the rigid bundle of hairs behind the upper incisors, which is crucial to efficiently peel saltbrush leaves and probably explains its broader distribution relative to P aureus.

Keywords: octodontid rodents; adaptive radiation; saltational chromosomal repatterning; octodontid evolution; introgressive hybridization; Tympanoctomys barrerae; Pipanacoctomys aureus; genome duplication; mammals; deserticolous species

Chapter.  6375 words.  Illustrated.

Subjects: Zoology and Animal Sciences

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