TY - JOUR UR - https://doi.org/10.7287/peerj.preprints.176v1 DO - 10.7287/peerj.preprints.176v1 TI - ­Geometric morphometric analysis of snout shape in extant ruminants (Ungulata, Artiodactyla) AU - Tennant,Jonathan P. AU - MacLeod,Norman DA - 2013/12/27 PY - 2013 KW - Snout shape KW - Geometric morphometrics KW - Ruminants KW - Ungulates KW - Functional morphology KW - Ecology KW - Palaeoecology KW - Mammals AB - Snout shape is a prominent aspect of herbivore feeding ecology, controlling both forage selectivity and intake rate. Many previous investigations have suggested that ruminant feeding classes can be discriminated via snout shape, with grazing and browsing species attributed ‘blunt’ and ‘pointed’ snouts respectively, with an intermediate sub-grouping. This aspect of functional ecology is analysed for the first time using a statistically rigorous geometry-based framework to compare the two-dimensional profiles of the premaxilla in ventral aspect for a large sample of ruminant species. Our results suggest that, when a sample of browsing and grazing ruminants are classified ecologically based on a range of independent indicators of their feeding strategy, they cannot be fully discriminated on the basis of their premaxilla profile shape. Instead, our sample forms a shape variation continuum with overlap between groupings, but with a 78 percent chance of successful categorisation. Moreover, previously used terminology such as ‘pointed’ and ‘blunt’ are largely inadequate for delimiting snout shape varieties, insofar as these terms lack the descriptive power to define the morphological disparity demonstrated. These results suggest that previous attempts to use snout shape as a proxy for feeding style in ruminants may have been biased due to under-sampling of this highly diverse group and to lack of geometric rigour in the assessment of shape data. Alternatively, conflicting or inadequate evidence in defining ‘browsers’ and ‘grazers’ could have caused incorrect assignment to ecological groups, distorting our analyses. The relation between snout shape and body mass are also documented. VL - 1 SP - e176v1 T2 - PeerJ PrePrints JO - PeerJ PrePrints J2 - PeerJ PrePrints SN - 2167-9843 ER -