TY - JOUR
T1 - Mechanical properties of the California sea lion (Zalophus californianus) and northern elephant seal (Mirounga angustirostris) lower jaws explain trophic plasticity
AU - Nieto-Miranda, J. Jesús
AU - Aguilar-Medrano, Rosalía
AU - Hernández-Camacho, Claudia J.
AU - Peredo, Carlos Mauricio
AU - Cruz-Escalona, Víctor Hugo
N1 - Publisher Copyright:
© 2023 American Association for Anatomy.
PY - 2023/10
Y1 - 2023/10
N2 - The fossil record of pinnipeds documents a suite of morphological changes that facilitate their ecological transition from a terrestrial to an aquatic lifestyle. Among these is the loss of the tribosphenic molar and the behavior typically associated with it in mammals: mastication. Instead, modern pinnipeds exhibit a broad range of feeding strategies that facilitate their distinct aquatic ecologies. Here, we examine the feeding morphology of two species of pinnipeds with disparate feeding ecologies: Zalophus californianus, a specialized raptorial biter, and Mirounga angustirostris, a suction specialist. Specifically, we test whether the morphology of the lower jaws facilitates trophic plasticity in feeding for either of these species. We used finite element analysis (FEA) to simulate the stresses during the opening and closing of the lower jaws in these species to explore the mechanical limits of their feeding ecology. Our simulations demonstrate that both jaws are highly resistant to the tensile stresses experienced during feeding. The lower jaws of Z. californianus experienced the maximum stress at the articular condyle and the base of the coronoid process. The lower jaws of M. angustirostris experienced the maximum stress at the angular process and were more evenly distributed throughout the body of the mandible. Surprisingly, the lower jaws of M. angustirostris were even more resistant to the stresses experienced during feeding than those of Z. californianus. Thus, we conclude that the superlative trophic plasticity of Z. californianus is driven by other factors unrelated to the mandible's tensile resistance to stress during feeding.
AB - The fossil record of pinnipeds documents a suite of morphological changes that facilitate their ecological transition from a terrestrial to an aquatic lifestyle. Among these is the loss of the tribosphenic molar and the behavior typically associated with it in mammals: mastication. Instead, modern pinnipeds exhibit a broad range of feeding strategies that facilitate their distinct aquatic ecologies. Here, we examine the feeding morphology of two species of pinnipeds with disparate feeding ecologies: Zalophus californianus, a specialized raptorial biter, and Mirounga angustirostris, a suction specialist. Specifically, we test whether the morphology of the lower jaws facilitates trophic plasticity in feeding for either of these species. We used finite element analysis (FEA) to simulate the stresses during the opening and closing of the lower jaws in these species to explore the mechanical limits of their feeding ecology. Our simulations demonstrate that both jaws are highly resistant to the tensile stresses experienced during feeding. The lower jaws of Z. californianus experienced the maximum stress at the articular condyle and the base of the coronoid process. The lower jaws of M. angustirostris experienced the maximum stress at the angular process and were more evenly distributed throughout the body of the mandible. Surprisingly, the lower jaws of M. angustirostris were even more resistant to the stresses experienced during feeding than those of Z. californianus. Thus, we conclude that the superlative trophic plasticity of Z. californianus is driven by other factors unrelated to the mandible's tensile resistance to stress during feeding.
KW - raptorial biter
KW - suction specialist
KW - temporomandibular joint
KW - trophic plasticity
UR - http://www.scopus.com/inward/record.url?scp=85148375981&partnerID=8YFLogxK
U2 - 10.1002/ar.25180
DO - 10.1002/ar.25180
M3 - Artículo
C2 - 36794994
AN - SCOPUS:85148375981
SN - 1932-8486
VL - 306
SP - 2597
EP - 2609
JO - Anatomical Record
JF - Anatomical Record
IS - 10
ER -