Regular Article
Nails and claws in primate evolution

https://doi.org/10.1006/jhev.1998.0263Get rights and content

Abstract

The issue of whether nails or claws were present on the digits of the last common ancestor of living primates is central to the understanding of the ecological context in which the order originated. Two lines of evidence are available, the shape (claw, nail, toilet-claw) and the histological structure (one or two horny strata). Here we review the existing data regarding the shape and histological structure of cheirideal appendages in primates and present new information from a wide range of living primates. We demonstrate the presence of a typical toilet-claw inDaubentonia madagascariensisand discuss its consequences, since the alleged lack of such structures in this species has long obscured the issue. The general view that primate nails, with the exception of those in New World primates, consist of only one layer is disproved by the presence of two distinct strata in the nails of the feet of three out of seven catarrhine species examined, as well as inLemur catta. The combined new and old data indicate that the last common ancestor of the extant primates had lost the typical mammalian claws of its ancestors and developed nails on all pedal digits except digit II, which bore a toilet-claw. All nails as well as the toilet-claw originally consisted of two layers. We present a new hypothesis regarding the adaptational significance of these changes.

References (47)

  • M.H. Day et al.

    The contrahens muscle layer inTarsius

    Folia primatol.

    (1975)
  • J.G. Fleagle

    Primate Adaptation and Evolution

    (1988)
  • S.M. Ford

    Callitrichids as phyletic dwarfs, and the place of the Callitrichidae in Platyrrhini

    Primates

    (1980)
  • J.L. Franzen

    Ein neuer Primate aus dem Mitteleozän der Grube Messel (Deutschland, S-Hessen)

    Cour. Forsch.-Inst. Senckenberg

    (1987)
  • J.L. Franzen

    Ein weiterer Primatenfund aus der Grube Messel bei Darmstadt

    Cour. Forsch.-Inst. Senckenberg

    (1988)
  • P.A. Garber

    Locomotor behavior and feeding ecology of the Panamanian tamarin (Saguinus oedipus geoffroyi

    Int. J. Primatol.

    (1980)
  • P.A. Garber

    Feeding ecology and behaviour of the genus Saguinus

  • H. Giersberg et al.

    Vergleichende Anatomie der Wirbeltiere. Band I: Integument, Sinnesorgane, Nervensystem

    (1979)
  • W.K. Gregory

    On the structure and relations ofNotharctus

    Mem. Am. Mus. nat. Hist. (n.s.)

    (1920)
  • C.P. Groves

    Taxonomy and phylogeny of prosimians

  • C.P. Groves

    A Theory of Human and Primate Evolution

    (1991)
  • M.W. Hamrick

    Functional and adaptive significance of primate pads and claws: evidence from New World anthropoids

    Am. J. phys. Anthrop.

    (1998)
  • W.C.O. Hill

    Primates: Comparative Anatomy and Taxonomy

    (1953)
  • Cited by (0)

    H. HoferA. H. SchultzD. Starck

    View full text