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A unique feeding strategy of the extinct marine mammal <i>Kolponomos</i>: convergence on sabretooths and sea otters Project ID: 00000C193 Public
22 Media · 7 Specimens · Managed by: Jack Tseng

Mammalian molluscivores feed mainly by shell-crushing or suction-feeding. The extinct marine arctoid, <i>Kolponomos</i>, has been interpreted as an otter-like shell-crusher based on similar dentitions. However, neither the masticatory biomechanics of the shell-crushing adaptation, nor the way <i>Kolponomos</i> may have captured hard-shelled prey, have been tested. Based on mandibular symphyseal morphology shared by <i>Kolponomos</i> and sabretoothed carnivores, we hypothesize a sabretooth-like mechanism for <i>Kolponomos</i> prey-capture, whereby the mandible functioned as an anchor. Torque generated from jaw closure and head flexion was used to dislodge prey by prying, with prey then crushed using cheek teeth. We test this hypothesized feeding sequence using phylogenetically-informed biomechanical simulations and shape analyses, and find a strongly supported, shared high mandibular stiffness in simulated prey-capture bites and mandibular shape in <i>Kolponomos</i> and the sabretoothed cat <i>Smilodon</i>. These two distantly related taxa converged on using mandibles to anchor cranial torquing forces when prying substrate-bound prey in the former and sabre-driving forces during prey-killing in the latter. Simulated prey-crushing bites indicate that <i>Kolponomos</i> and sea otters exhibit alternative structural stiffness-bite efficiency combinations in mandibular biomechanical adaptation for shell-crushing. This unique feeding system of Kolponomos exemplifies a mosaic of form-function convergence relative to other Carnivora.

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  ID Part Object Taxonomy Type Date Added Publication Status  
000009731 cranium amnh:fm:14349 Smilodon fatalis Mesh 2016-03-02 Restricted Download  
000009732 mandible amnh:fm:14349 Smilodon fatalis Mesh 2016-03-02 Restricted Download  
000009730 mandible amnh:fm:14349 Smilodon fatalis Mesh 2016-03-02 Restricted Download  
000009729 cranium amnh:fm:14349 Smilodon fatalis Mesh 2016-03-02 Restricted Download  
000009063 mandible (posterior 2/3) amnh:fm:14349 Smilodon fatalis Volumetric Image Series 2016-02-09 Restricted Download  
000009060 mandible (anterior third) amnh:fm:14349 Smilodon fatalis Volumetric Image Series 2016-02-09 Restricted Download  
000009404 Skull AMNH:Mammals:M-34408 Ursus arctos horribilis Mesh 2016-02-18 Open Download  
000009087 Skull AMNH:Mammals:M-34408 Ursus arctos horribilis Mesh 2016-02-09 Open Download  
000009057 Skull AMNH:Mammals:M-34408 Ursus arctos horribilis Volumetric Image Series 2016-02-09 Open Download  
000009086 Skull AMNH:Mammals:M-113745 Panthera pardus Mesh 2016-02-09 Open Download  
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