The evolution of feeding adaptations of the aquatic sloth Thalassocnus
The evolution of feeding adaptations of the aquatic sloth Thalassocnus
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DOI：
10.1671/2429b
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发表时间：
2004-06-11
影响因子：
1.4
通讯作者：
Urbina, M
中科院分区：
文献类型：
--
作者：
De Muizon, C;McDonald, HG;Urbina, M
从中新世晚期到上新世晚期，生活在秘鲁沿海的五个水生树懒代表了Thalassocnus。这些物种的颅骨和下颌解剖结构的详细比较表明不同的摄食适应。三种较古老的海颌目（T. antiquus、T. natans和T. littoralis）可能是部分食草动物（中间或混合食草动物），下颌运动的横向分量非常小。它们可能部分以搁浅的海草或海草为食，或者在非常浅的水域（不到1米）中进食，这可以从它们的臼齿状牙齿上大量的齿纹中看出。两个较年轻的物种（T. carolomartini和T. yaucensis）比三个较老的物种更专门的食草动物，并且在其下颌运动中具有明显的横向成分。它们的牙齿几乎完全没有牙纹。这两个物种可能只在比老物种更深的水里觅食。
The aquatic sloth Thalassocnus is represented by five species that lived along the coast of Peru from the late Miocene through the late Pliocene. A detailed comparison of the cranial and mandibular anatomy of these species indicates different feeding adaptations. The three older species of Thalassocnus (T. antiquus, T natans, and T. littoralis) were probably partial grazers (intermediate or mixed feeders) and the transverse component of mandibular movement was very minor, if any. They were probably feeding partially on stranded sea weeds or sea grasses, or in very shallow waters (less than 1 m) as indicated by the abundant dental striae of their molariform teeth created by ingestion of sand. The two younger species (T. carolomartini and T. yaucensis) were more specialized grazers than the three older species and had a distinct transverse component in their mandibular movement. Their teeth almost totally lack dental striae. These two species were probably feeding exclusively in the water at a greater depth than the older species.