Kolmann Matthew A, Crofts Stephanie B, Dean Mason N, Summers Adam P, Lovejoy Nathan R
Department of Ecology and Evolutionary Biology, University of Toronto at Scarborough, 1265 Military Trail, Toronto, Ontario, Canada M1C 1A4
Department of Biological Sciences, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA.
J Exp Biol. 2015 Dec;218(Pt 24):3941-9. doi: 10.1242/jeb.127340. Epub 2015 Nov 13.
All stingrays in the family Myliobatidae are durophagous, consuming bivalves and gastropods, as well as decapod crustaceans. Durophagous rays have rigid jaws, flat teeth that interlock to form pavement-like tooth plates, and large muscles that generate bite forces capable of fracturing stiff biological composites (e.g. mollusk shell). The relative proportion of different prey types in the diet of durophagous rays varies between genera, with some stingray species specializing on particular mollusk taxa, while others are generalists. The tooth plate module provides a curved occlusal surface on which prey is crushed, and this curvature differs significantly among myliobatids. We measured the effect of jaw curvature on prey-crushing success in durophagous stingrays. We milled aluminum replica jaws rendered from computed tomography scans, and crushed live mollusks, three-dimensionally printed gastropod shells, and ceramic tubes with these fabricated jaws. Our analysis of prey items indicate that gastropods were consistently more difficult to crush than bivalves (i.e. were stiffer), but that mussels require the greatest work-to-fracture. We found that replica shells can provide an important proxy for investigations of failure mechanics. We also found little difference in crushing performance between jaw shapes, suggesting that disparate jaws are equally suited for processing different types of shelled prey. Thus, durophagous stingrays exhibit a many-to-one mapping of jaw morphology to mollusk crushing performance.
所有鲼科的黄貂鱼都是食硬壳动物，以双壳类、腹足类以及十足目甲壳类动物为食。食硬壳动物的黄貂鱼有着坚硬的颌骨、扁平的牙齿，这些牙齿相互交错形成类似铺路石的齿板，还有强大的肌肉，能够产生足以咬碎坚硬生物复合材料（如软体动物外壳）的咬合力。食硬壳动物的黄貂鱼食谱中不同猎物类型的相对比例因属而异，一些黄貂鱼物种专门捕食特定的软体动物分类群，而其他一些则是杂食性的。齿板模块提供了一个弯曲咬合面，猎物在上面被压碎，这种曲率在鲼科动物之间有显著差异。我们测量了颌骨曲率对食硬壳动物黄貂鱼压碎猎物成功率的影响。我们根据计算机断层扫描制作了铝制仿颌骨，并用这些制作的颌骨压碎活的软体动物、三维打印的腹足类动物外壳和陶瓷管。我们对猎物的分析表明，腹足类动物始终比双壳类动物更难压碎（即更坚硬），但贻贝需要最大的破碎功。我们发现仿贝壳可以为失效力学研究提供重要的替代物。我们还发现不同颌骨形状在压碎性能上差异不大，这表明不同的颌骨同样适合处理不同类型的带壳猎物。因此，食硬壳动物的黄貂鱼在颌骨形态与软体动物压碎性能之间呈现出多对一的映射关系。
