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The Interpretive Power of Infraorbital Foramen Area in Making Dietary Inferences in Extant Apes
Author(s) -
Muchlinski Magdale.,
Deane Andrew S.
Publication year - 2014
Publication title -
the anatomical record
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.678
H-Index - 62
eISSN - 1932-8494
pISSN - 1932-8486
DOI - 10.1002/ar.22953
Subject(s) - gorilla , frugivore , biology , hylobates , hominidae , allopatric speciation , zoology , pongo pygmaeus , primate , guild , evolutionary biology , ecology , habitat , biological evolution , paleontology , population , genetics , demography , sociology
The infraorbital foramen (IOF) is located below the orbit and transmits the sensory infraorbital nerve (ION) to mechanoreceptors located throughout the maxillary region. The size of the IOF correlates with the size of the ION; thus, the IOF appears to indicate relative touch sensitivity of maxillary region. In primates, IOF size correlates well with diet. Frugivores have relatively larger IOFs than folivores or insectivores because fruit handling/processing requires increased touch sensitivity. However, it is unknown if the IOF can be used to detect subtle dietary differences among closely related hominoid species. Hominoids are traditionally grouped into broad dietary categories, despite the fact that hominoid diets are remarkably diverse. This study examines whether relative IOF size is capable of differentiating among the dietary preferences of closely related species with overlapping, yet divergent diets. We measured IOF area in Hylobates lar , Symphalangus syndactulus , Pongo pygmaeus spp., Pan troglodytes , Gorilla gorilla, Gorilla beringei graueri , and Gorilla beringei beringei . We classified each species as a dedicated folivore, mixed folivore/frugivore, soft object frugivore, or hard object frugivore. The IOF is documented to be larger in more frugivorous species and smaller in more folivorous taxa. Interestingly, G.b. beringei , had the largest relative IOF of any gorilla, despite being a dedicated folivore. G.b. beringei does have unique food processing behavior that relies heavily on maxillary mechanoreception, thus this finding is not entirely unsupported behaviorally. The results of this study provide evidence that the IOF is an informative feature in interpretations of fossil apes. Anat Rec, 297:1377–1384, 2014. © 2014 Wiley Periodicals, Inc.