Structure and function of platyrrhine caudal vertebrae

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

The prehensile tail may have evolved twice (in parallel) in New World monkeys (platyrrhines), suggesting it is an effective adaptation to negotiating arboreal habitats. Yet, despite the obvious importance of the prehensile tail for balance, feeding behavior, and locomotion, the structural differences between prehensile and nonprehensile tails are poorly understood. Previous studies showed that some linear measurements of caudal vertebrae are capable of distinguishing prehensile from nonprehensile tails but only in the distal parts of the vertebral sequence. This study examines structural properties of the tail with external measurements that are selected to better approximate resistance to bending/torsion while also examining vertebral cross-sectional geometry with computed tomography - a direct measure of resistance to bending/torsion. Specifically, this study tests the hypotheses that the caudal vertebrae (and the tail as a whole) of prehensile-tailed platyrrhines are structured to resist higher torsional and bending stresses than their functional analogues in nonprehensile-tailed platyrrhines, and that the predicted differences become more drastic further distally within the sequence. Results of this study indicate that prehensile and nonprehensile tails are structured differently. Prehensile tails are characterized by longer proximal tail regions than nonprehensile tails. Furthermore, the hemal processes (the distal attachment for the primary tail flexors) of prehensile tail vertebrae are better developed and can distinguish prehensile from nonprehensile tails better than traditionally used external measurements. Finally, results confirm predictions that prehensile tail caudal vertebrae are capable of withstanding higher torsional and bending stresses than their nonprehensile tail counter-parts, and that these disparities become more pronounced further distally within the sequence.

Original languageEnglish (US)
Pages (from-to)730-745
Number of pages16
JournalAnatomical Record
Volume293
Issue number4
DOIs
StatePublished - Apr 2010
Externally publishedYes

Fingerprint

vertebrae
Tail
Spine
tail
torsion
locomotion
feeding behavior
tomography
geometry
habitat
prediction
Platyrrhini
Cebidae
Negotiating
Feeding Behavior
Locomotion
computed tomography
Ecosystem

Keywords

  • Atelinae
  • Biomechanics
  • Cebus
  • Functional convergence
  • Hemal process
  • New world monkeys
  • pQCT
  • Prehensile tail
  • Torsion

ASJC Scopus subject areas

  • Anatomy
  • Histology
  • Ecology, Evolution, Behavior and Systematics
  • Biotechnology

Cite this

Structure and function of platyrrhine caudal vertebrae. / Organ, Jason.

In: Anatomical Record, Vol. 293, No. 4, 04.2010, p. 730-745.

Research output: Contribution to journalArticle

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