Galagidae (Lorisoidea, Primates)

Terry Harrison

    Research output: Chapter in Book/Report/Conference proceedingChapter

    Abstract

    An additional specimen of a fossil galagid was recently recovered from the Upper Laetolil Beds at Laetoli in northern Tanzania. This new find represents the most complete specimen of a galagid known from Laetoli, and comprises associated partial right and left mandibular corpora. The galagid material from Laetoli can all be attributed to a single species, previously referred to as Galago sadimanensis. However, the taxon is sufficiently distinct from all extant galagids, as well as stem galagids from the Miocene of East Africa, to be placed in its own genus, Laetolia. The fossil record of galagids from the Pliocene of Africa is exceedingly poor, and Laetolia sadimanensis represents the best-known form. Laetolia can be distinguished from other galagids by its unique suite of morphological features. The stout and vertical implantation of P2, the steeply inclined and robust symphysis, and the relatively deep corpus are all specialized features that are probably functionally linked. However, Laetolia has a less molariform P4 than extant galagids, and it can be inferred to represents their primitive sister taxon. Based on molecular clock estimates, extant galagids shared a last common ancestor during the late Oligocene. It is interesting, therefore, to discover a sister taxon of extant galagids surviving in East Africa until at least the Pliocene, contemporary with more advanced crown members of the clade. From a paleoecological perspective, the occurrence of fossil galagids at Laetoli implies the presence of habitats with at least a sparse coverage of trees and/or thorn bush.

    Original languageEnglish (US)
    Title of host publicationPaleontology and Geology of Laetoli
    Subtitle of host publicationHuman Evolution in Context
    PublisherSpringer
    Pages75-81
    Number of pages7
    Volume2: Fossil Hominins and the Associated Fauna
    DOIs
    StatePublished - 2011

    Publication series

    NameVertebrate Paleobiology and Paleoanthropology
    Number9789048199617
    ISSN (Print)1877-9077

    Keywords

    • Galagids
    • Laetoli
    • Mabaget formation
    • Phylogeny
    • Pliocene

    ASJC Scopus subject areas

    • Ecology, Evolution, Behavior and Systematics
    • Ecology
    • Palaeontology

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  • Cite this

    Harrison, T. (2011). Galagidae (Lorisoidea, Primates). In Paleontology and Geology of Laetoli: Human Evolution in Context (Vol. 2: Fossil Hominins and the Associated Fauna, pp. 75-81). (Vertebrate Paleobiology and Paleoanthropology; No. 9789048199617). Springer. https://doi.org/10.1007/978-90-481-9962-4_5