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Novel adaptations of the pinniped (Mammalia:Carnivora) jaw anatomy to aquatic prey‐capture
Author(s) -
Jones Katrina Elizabeth,
Ruff Chris,
Goswami Anjali
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.lb8
Subject(s) - biting , anatomy , mastication , biology , bite force quotient , mammal , symphysis , predation , zoology , ecology , paleontology
Biomechanical models of jaw anatomy in terrestrial mammals often focus on mastication as the driving force for adaptation. As marine mammals, pinnipeds (e.g.seals) use their jaws primarily for prey‐capture; but not for mastication. Here we reveal the functional adaptations of jaw anatomy to novel marine feeding behavior; filter feeding, suction feeding and “grip and tear” feeding. We measured 100 mandibles, representing 25 of 34 extant species, using a digitizer to capture co‐ordinate data for 15 homologous landmarks. Relevant linear measurements were extracted from the landmark data. We then used X‐ray data to reconstruct cortical thickness to calculate section modulus (strength estimate) for four species (n=25). We compared the specialist feeders for each measure, based on expected mechanical scaling. Filter feeders displayed a very long toothrow, which increases sieve area, and a highly elliptical mandibular symphysis to prevent wishboning during the expulsion of water. The suction feeding jaw was shorter with a weaker mandible, lower bite force and diminutive canines, due to the reduced requirement for biting. Grip and tear feeders were adapted for a large gape (longer jaw), strong biting, and a posteriorly directed muscle vector for capturing large prey. This study elucidates novel adaptation of mammal jaw anatomy to the biomechanical challenges of prey‐capture in the marine realm.