來自約旦中部的一件晚白堊紀滄龍化石顯示了一個帶腳蹼的尾巴,，它表明這些蜥蜴會像鯊魚一樣地游泳。這項研究發(fā)表在本期Nature Communications上,。
滄龍在距今大約9800萬年-6600萬年前是居支配地位的海洋爬行動物。關于滄龍祖先的沖突理論，再加上化石記錄中軟組織證據的缺乏以及對滄龍身體構造的不正確描述和重建，導致了這樣一個普遍假設：這些爬行動物游泳速度慢,。Lindgren及同事分析了具有保存極好的軟組織的一個化石材料，發(fā)現了一個新月狀的尾鰭,，與鯨和魚龍（與海豚相似的海洋爬行動物）的相似,。
研究人員通過將該化石的形態(tài)與現代鯊魚做比較得出這樣的結論：滄龍能高效率地游泳。該研究還表明,，這種特征鮮明的尾巴在占據相似環(huán)境的幾個類群中是獨立演化的（生物谷Bioon.com）。
生物谷推薦的英文摘要
Nature Communications DOI:10.1038/ncomms3423
Soft tissue preservation in a fossil marine lizard with a bilobed tail fin
Johan Lindgren,，Hani F. Kaddumi & Michael J. Polcyn
Mosasaurs are secondarily aquatic squamates that became the dominant marine reptiles in the Late Cretaceous about 98–66 million years ago. Although early members of the group possessed body shapes similar to extant monitor lizards,， derived forms have traditionally been portrayed as long， sleek animals with broadened,， yet ultimately tapering tails. Here we report an extraordinary mosasaur fossil from the Maastrichtian of Harrana in central Jordan,， which preserves soft tissues， including high fidelity outlines of a caudal fluke and flippers. This specimen provides the first indisputable evidence that derived mosasaurs were propelled by hypocercal tail fins,， a hypothesis that was previously based on comparative skeletal anatomy alone. Ecomorphological comparisons suggest that derived mosasaurs were similar to pelagic sharks in terms of swimming performance,， a finding that significantly expands our understanding of the level of aquatic adaptation achieved by these seagoing lizards.
