Dear colleagues,
We are pleased to announce the publication of the following paper in Journal of Morphology:
Barroso, C., Cranford, T. W., and Berta, A. (2012). Shape analysis of
odontocete mandibles: Functional and evolutionary implications. J.
Morphol., 273: 1021–1030. doi: 10.1002/jmor.20040
Abstract. Odontocete mandibles serve multiple functions, including feeding and
hearing. We consider that these two major functions have their primary
influence in different parts of the mandibles: the anterior feeding
component and the posterior sound reception component, though these
divisions are not mutually exclusive. One hypothesis is that sound
enters the hearing apparatus via the pan bone of the posterior mandibles
(Norris, Evolution and Environment,1968,
pp 297–324). Another viewpoint, based on finite element models,
suggests that sound enters primarily through the gular region and the
opening created by the absent medial lamina of the posterior mandibles.
This unambiguous link between form and function has catalyzed this
study, which uses Geometric Morphometrics to quantify mandibular shape
across all major lineages of Odontoceti. The majority of shape variation
was found in the anterior (feeding) region: Jaw Flare (45.0%) and
Symphysis Elongation (35.5%). Shape differences in the mandibular
foramen, within the posterior (sound reception) region, also accounted
for a small portion of the total variation (10.9%). The mandibles are an
integral component of the sound reception apparatus in toothed whales
and the geometry of the mandibular foramen likely plays a role in
hearing. Furthermore, model goodness-of-fit tests indicate that
mandibular foramina shapes, which appear conserved, evolved under a
selective regime, possibly driven by sound reception requirements across
Odontoceti. J. Morphol. © 2012 Wiley Periodicals, Inc.
Sincerely,
Celia Barroso
San Diego State University