全长47厘米、形似水生蜥蜴,超长的尾巴尤其特别——在云南省红河州,科学家发现了一种约2.44亿年前的海生爬行动物,命名为“长尾红河龙”。这是目前我国发现的肿肋龙科最古老的化石证据,相关成果已发表在国际学术期刊《科学报告》上。
▲ 图为长尾红河龙。图源:中科院古脊椎所
Earlier this month, Chinese scientists reported the discovery of a complete fossil skeleton of a new species of marine reptile in Yunnan province that roamed the ancient sea about 244 million years ago during the Triassic period.
The prehistoric creature was named Honghesaurus longicaudalis, and it possessed the longest tail of any known pachypleurosaurs. It is also China's oldest fossil record of this family of reptiles.
世界上尾巴相对最长的肿肋龙类
肿肋龙类包括肿肋龙科和贵州龙科。其中,肿肋龙科最早出现在中三叠世早期,在中三叠世末期灭绝。红河州发现的这块长尾红河龙化石全长达47.1厘米,尾巴占据了其身体总长度的一半以上,有25.4厘米。
Pachypleurosaurs are a group of small to medium-sized lizard-like marine reptiles from the early to middle Triassic. The fossil is 47.1 centimeters long, and its tail spans more than half of its body length at 25.4 cm.
▲ 长尾红河龙前后肢部分。图源:中科院古脊椎所
主导此项研究的中科院古脊椎动物与古人类研究所研究员徐光辉介绍,长尾红河龙共有121块脊椎骨,其中的69块组成了长长的尾巴,占全长的54%,是世界上尾巴相对最长的肿肋龙类。相比之下,人类则拥有33块脊椎骨。
Remarkably, the tail of the discovered reptile contains 69 vertebrae, far more than any other known pachypleurosaur, which typically have no more than 58. Humans in comparison have just 33 vertebrae.
尾巴长意味着什么?
对于爬行动物来说,尾巴的长短非常重要。一些爬行动物会利用它们的长尾巴来保持平衡,如亚洲草蜥和绿玄武岩,而海洋爬行动物则利用它们的尾巴来推进和操纵。
In the world of reptiles, the size of the tail matters. Some species use their long tails for balance, such as the Asian grass lizard and the green basilisk, while marine reptiles use their tails for propulsion and maneuverability.
▲ 长尾红河龙头骨及复原图。图源:中科院古脊椎所
“长尾红河龙生活在浅海环境,吃小鱼小虾、软体动物等。”徐光辉说,从它长长的躯干和较纤细的前、后肢可以判断,长尾红河龙在浅海环境中主要采用侧向波动的方式前进,它超长的尾部可以进一步提高侧向波动的效率,帮助它们游得更快、更稳。
Scientists believe its long body paired with a lengthy tail could have provided it with good energy efficiency and maneuverability in water, making it an excellent swimmer, according to a study published in the journal Scientific Reports.
比“贵州龙”早约400万年
据介绍,在约2.52亿年前的二叠纪生物大灭绝之后,海洋生态系统在三叠纪发生了重大变革,演化出包括肿肋龙类在内的种类繁多、门类丰富的海生爬行动物。
1854年,欧洲就发现了肿肋龙类化石。我国最早命名的海生爬行动物也是肿肋龙类,即在20世纪50年代发现并命名的“胡氏贵州龙”。
▲ 图为胡氏贵州龙。图源:中科院古脊椎所
1957年,中国地质博物馆的胡承志先生和贵州省博物馆的曹泽田先生在贵州兴义绿荫村采集到一批小型爬行动物化石,经鉴定属于肿肋龙亚目肿肋龙科的一个新属种,特命名为“胡氏贵州龙”,以纪念最初采集到这一化石的胡承志同志。胡氏贵州龙的发现代表着原始鳍龙类在整个亚州的第一次发现。
As early as 1854, scientists had discovered Pachypleurosaurus fossils in the Alps. The first named marine reptile discovered in China also happened to belong to this family. It was called Keichousaurus, and was discovered by renowned Chinese paleontologist Hu Chengzhi in 1957.
此次发现的长尾红河龙比贵州龙早约400万年,为研究当时的海洋生态系统和海生爬行动物演化提供了新的化石证据。
The discovery of Honghesaurus longicaudalis predates Keichousaurus by about 4 million years, providing new fossil evidence for the study of the marine ecosystem and the evolution of marine reptiles at that time.
编辑:商桢

记者:张之豪
来源:科技日报 中国日报 化石网
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