Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA.
Museo di Storia Naturale di Milano, Corso Venezia 55, 20121 Milan, Italy.
Science. 2014 Sep 26;345(6204):1613-6. doi: 10.1126/science.1258750. Epub 2014 Sep 11.
We describe adaptations for a semiaquatic lifestyle in the dinosaur Spinosaurus aegyptiacus. These adaptations include retraction of the fleshy nostrils to a position near the mid-region of the skull and an elongate neck and trunk that shift the center of body mass anterior to the knee joint. Unlike terrestrial theropods, the pelvic girdle is downsized, the hindlimbs are short, and all of the limb bones are solid without an open medullary cavity, for buoyancy control in water. The short, robust femur with hypertrophied flexor attachment and the low, flat-bottomed pedal claws are consistent with aquatic foot-propelled locomotion. Surface striations and bone microstructure suggest that the dorsal "sail" may have been enveloped in skin that functioned primarily for display on land and in water.
我们描述了恐龙棘龙（Spinosaurus aegyptiacus）半水生生活方式的适应特征。这些适应特征包括将肉质的鼻孔向后收缩到靠近头骨中部的位置，以及伸长的颈部和躯干，使身体重心向前移动到膝关节之前。与陆地兽脚亚目恐龙不同，骨盆带缩小，后肢短，所有的肢骨都是实心的，没有开放的骨髓腔，以控制在水中的浮力。短而粗壮的股骨有肥大的屈肌附着点，低矮、平底的跖骨爪表明，这种恐龙可能主要通过脚部在水中推动身体来移动。表面的条纹和骨组织学表明，背部的“帆”可能被一层皮肤包裹，其主要功能是在陆地和水中展示。
