Oryctos
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Accès privé :
| volume 4, 2002 |
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Peter J. Adam & Annalisa Berta, Evolution of Prey Capture Strategies and Diet in Pinnipedimorpha (Mammalia, Carnivora). Oryctos 4, 83-107
Pinnipeds represent a lineage of terrestrial carnivores that have secondarily adapted to a marine existence and must capture and process prey under water. We examined known diets and skull morphologies associated with different prey capture strategies in extant and fossil pinnipedimorphs using a phylogenetic context to reveal their evolutionary feeding history and diversity. Unlike their arctoid ancestors, no extant pinnipedimorph masticates food. Prey capture is accomplished by four methods, characterized by numerous craniodental features (in parentheses): 1) pierce feeding (homodonty; M1 anterior to dentary midlength; enlarged orbit); 2) suction feeding (elongate and vaulted palate; robust pterygoid hamuli; mandibular fusion); 3) filter feeding (high-crowned, intricately cusped postcanine teeth; upper and lower teeth interdigitating; post-dental ridges); and 4) grip and tear feeding (straight, sharply pointed postcanine cusps; enlarged incisors). Pierce feeding is typical of most pinnipedimorphs, while filter feeding is limited to extant crabeater seals and grip and tear feeding to living leopard seals. A tendency toward suction feeding occurs in at least four independent lineages (otariine sea lions, bearded seal, and dusignathine and odobenine walruses), although it is best developed in odobenines. Only a weak correlation between functional anatomy and diet was observed for extant taxa. For example, suction feeding is utilized by walruses to capture and consume benthic mollusks, but skulls with convergent evolution of suction associated characters are also well designed for capturing larger fish and squid (e.g. Otaria byronia).
Keywords : Pinnipedia, Phocidae, Otariidae, Odobenidae, Evolution, Adaptation, Feeding, Diet, Morphology, Skull
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