Zoological Studies

Vol. 50 No. 6, 2011

Substrate Use and Locomotor Modes of the Neotropical Pygmy Squirrel Sciurillus pusillus (E. Geoffroy, 1803) in French Guyana

Dionisios Youlatos

Department of Zoology, School of Biology, Aristotle Univ. of Thessaloniki, Thessaloniki GR-51424, Greece

Dionisios Youlatos (2011) The Neotropical pygmy squirrel Sciurillus pusillus is the smallest South American squirrel. This primitive sciurid is rarely encountered and exhibits morphological and behavioral specializations related to bark gleaning and bark and/or exudate feeding. The present account reports the 1st quantitative data on substrate use and locomotor patterns of S. pusillus from a high terra-firme forest in French Guyana. S. pusillus made extensive use of medium vertical supports. The most frequent locomotor modes were claw-climbing and reversion, an orthograde airborne switching mode. Quadrupedalism was used to a lesser extent. The behavioral repertoire of S. pusillus was examined in light of its postcranial morphological features. Together, they suggest a large degree of vertical trunk foraging for bark and/or exudates similar to what was reported for other pygmy squirrels in Africa and Asia. More-detailed studies are required to elucidate these patterns of morphological convergence in pygmy squirrels across tropical forests worldwide.

Key words: Sciuridae, French Guyana, Locomotion, Neotropical pygmy squirrel, Sciurillus pusillus.

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