科学家利用CT扫描重新检查一具近一个世纪前发现的头骨，从一具4500万年前的埃及化石中鉴定出一种新的鳄鱼属。该化石来自莫卡塔姆组，即雕刻大斯芬克斯的同一石灰岩地层。就像这座纪念碑一样，该头骨缺失了吻尖。
Scientists have identified a new crocodile genus from a 45-million-year-old Egyptian fossil after using CT scans to re-examine a skull recovered nearly a century ago. The fossil comes from the Mokattam Formation, the same limestone formation from which the Great Sphinx was carved. Like the monument, the skull is missing the tip of its snout.
来自埃及、英国、瑞典和德国的研究人员将该动物命名为Herugavialis cairensis。研究成果发表在《皇家学会开放科学》上。
Researchers from Egypt, the UK, Sweden and Germany have named the animal Herugavialis cairensis. The findings were published in Royal Society Open Science.
该动物最早于1927年被描述为Tomistoma cairense，归入与现存假鳄（一种长吻鳄）同一属。但新的检查揭示了其头骨结构和演化关系上的差异。其显著特征包括隆起、突出的眼窝。
The animal was first described in 1927 as Tomistoma cairense, placing it in the same genus as the living false gharial, which has a long, narrow snout. But the new examination revealed differences in the skull's structure and the animal's evolutionary relationships. Among its distinctive features were raised, projecting eye sockets.
这些差异促使研究人员将该物种置于一个单独的属中，改变了延续近一个世纪的分类。
Those differences prompted the researchers to place the species in a separate genus, changing a classification that had stood for almost a century.
瑞典自然历史博物馆的Paul Burke领导了该研究，伦敦大学学院的Philip Mannion共同领导。
Paul Burke of the Swedish Museum of Natural History led the study, co-led by Philip Mannion of University College London.
Mannion在声明中表示，化石缺失的吻尖与斯芬克斯缺失的鼻子之间的相似性有助于启发该名称，以纪念埃及神祇荷鲁斯。约4500万年前，该地区大部分处于浅海之下。赫鲁鳄与至少另外两种长吻鳄共同生活。该动物属于一个类群，其仅存的成员是印度鳄和假鳄。
Mannion said in a statement that the resemblance between the fossil's missing snout tip and the Sphinx's absent nose helped inspire the name, which honours the Egyptian god Heru. About 45 million years ago, much of the region lay beneath shallow seas. Herugavialis lived alongside at least two other species of long-snouted crocodiles. The animal belonged to a group whose only surviving members are the Indian gharial and false gharial.
化石显示，它们的亲属曾拥有广泛的分布，已确认超过40个物种。
Fossils show that their relatives once had a far wider distribution, with more than 40 species recognised.
研究人员推测，气候变冷和海平面下降减少了地中海周围的适宜栖息地，而后来的变暖可能使其多样性得以恢复。
The researchers suggest that cooling and falling sea levels reduced suitable habitats around the Mediterranean, while later warming may have allowed their diversity to recover.
研究更多化石有助于解释这些古代鳄鱼如何扩散至地中海周围，以及为何后来从该地区消失。
Studying more fossils could help explain how these ancient crocodiles spread around the Mediterranean and why they later disappeared from the region.