Fossils show unexpected last refuge of ferocious land-living crocs
化石显示了凶猛的陆地鳄鱼意想不到的最后避难所
WASHINGTON, April 29 (Reuters) – After the demise of the dinosaurs following an asteroid strike 66 million years ago, mammals became Earth’s dominant land animals. But that does not mean they went unchallenged. In South America, for instance, nightmarish land-living crocs – cousins of today’s crocodiles and alligators – became apex predators.
路透社华盛顿 4 月 29 日电—6600 万年前， 恐龙在一次小行星撞击后灭绝 ， 哺乳动物成为地球上占主导地位的陆地动物。但这并不意味着他们没有受到挑战。例如，在南美洲，噩梦般的陆地鳄鱼-今天鳄鱼和短吻鳄的表亲-成为顶级掠食者。
This lineage of terrestrial crocs, called sebecids, lasted longer than previously believed, according to researchers who described fossils recently unearthed in the Dominican Republic that reveal that the islands of the Caribbean served as an unexpected last refuge for these ferocious predators.
根据研究人员的描述，最近在多米尼加共和国出土的化石表明，加勒比岛屿是这些凶猛掠食者意想不到的最后避难所。
Until now, the most recent fossils of sebecids were found in Colombia and dated to about 10.5-12.5 million years ago. The Dominican Republic fossils date to about 5-7 million years ago. The largest of the sebecids reached roughly 20 feet (6 meters) long, though the partial remains from the Dominican Republic indicate an animal up to about 7 feet (2 meters) long.
到目前为止，最新的 sebecids 化石是在哥伦比亚发现的，可以追溯到大约 1050 – 1250 万年前。多米尼加共和国的化石可以追溯到大约 500 – 700 万年前。最大的 sebecids 达到约 20 英尺（6 米）长，尽管多米尼加共和国的部分遗骸表明动物长达约 7 英尺（2 米）。
“These were the type of predators that one thinks were from the dinosaur times,” said Lazaro Viñola Lopez, a graduate student in paleontology at the University of Florida and lead author of the research published this week in the journal Proceedings of the Royal Society B.
“这些是人们认为来自恐龙时代的捕食者类型，”佛罗里达大学古生物学研究生拉扎罗·维尼奥拉·洛佩斯说，他是本周发表在《皇家学会学报 B》上的这项研究的主要作者。
Instead, Viñola Lopez said, sebecids were at the top of the food chain in South America during the age of mammals alongside terror birds, giant flightless birds up to about 10 feet (3 meters) tall with massive hooked beaks, and saber-toothed marsupials, counterparts to the saber-toothed cats of North America and elsewhere.
相反，Viñola 洛佩斯说，在哺乳动物时代，sebecids 位于南美洲食物链的顶端，与恐怖鸟类，巨大的不会飞的鸟类高达约 10 英尺（3 米），有巨大的钩状喙，剑齿有袋动物，与北美和其他地方的剑齿猫相对应。
Various types of crocs have inhabited Earth dating back to the Triassic Period more than 200 million years ago. Most, like the ones alive today, lived a semiaquatic lifestyle. But some conquered the marine realm and others lived exclusively on land, like the sebecids.
各种类型的鳄鱼居住在地球上，可以追溯到两亿多年前的三叠纪时期 。大多数，像今天活着的，过着半水生的生活方式。但有些人征服了海洋，另一些人则只生活在陆地上，比如塞贝西德人。
The sebecids were built differently than the usual semiaquatic crocs.
sebecids 的构造不同于通常的半水生鳄鱼。
They had longer legs and a more upright stance, capable of running quickly to chase down prey. They had a narrow and deep skull – superficially resembling that of a meat-eating dinosaur and much different from modern crocs that have a wider and shallower skull. And the teeth of sebecids were tall and narrow with fine serrations running along the edges for cutting through meat, also similar to carnivorous dinosaurs.
它们有更长的腿和更直立的姿势，能够快速奔跑追逐猎物。它们有一个狭窄而深的头骨-表面上类似于食肉恐龙，与现代鳄鱼的头骨更宽更浅有很大不同。而皮脂腺科动物的牙齿又高又窄，边缘有沿着细小的锯齿，用来切割肉类，也类似于食肉恐龙。
Like many other crocs, they had protective armor made of bony plates called scutes embedded in their skin.
像许多其他鳄鱼一样，它们的保护性盔甲由嵌入皮肤中的称为鳞甲的骨板制成。
The fossils found in the Dominican Republic in 2023 were a single tooth that closely resembled those of South American sebecids and two vertebrae with characteristics that enabled the researchers to definitively conclude that these remains belonged to a sebecid.
2023 年在多米尼加共和国发现的化石是一颗牙齿，非常类似于南美 sebecids 的牙齿和两块椎骨，其特征使研究人员能够明确地得出结论，这些遗骸属于 sebecid。
“It is amazing to think that these fast-moving, dinosaur-like terrestrial crocs with serrated teeth specialized for cutting meat survived in the Caribbean hunting sloths, rodents and whatever else was around up until just a few million years ago,” said study co-author Jonathan Bloch, curator of vertebrate paleontology at the Florida Museum of Natural History at the University of Florida.
“令人惊讶的是，这些快速移动的，像鳄鱼一样的陆地鳄鱼，锯齿状的牙齿专门用于切割肉类，在加勒比狩猎树懒，啮齿动物和其他任何东西中生存下来，直到几百万年前，”研究合着者乔纳森·布洛赫说，他是佛罗里达大学佛罗里达自然历史博物馆脊椎动物古生物学馆长。
The researchers said that fossils of two teeth apparently from a sebecid dating to about 18 million years ago that were previously discovered in Cuba and a similar one dating to around 29 million years previously found in Puerto Rico suggest that this lineage was widespread in the islands of the West Indies.
研究人员说，先前在古巴发现的两颗牙齿化石显然来自大约 1800 万年前的 sebecid，以及先前在波多黎各发现的大约 2900 万年前的类似牙齿，表明这种血统在西印度群岛广泛存在。
But how did land-living crocs from South America manage to get there? The researchers said their presence on the islands is another clue indicating there may have been a pathway of temporary land bridges or a chain of islands that permitted land animals to travel from South America to the Caribbean around 32-35 million years ago.
但是，来自南美洲的陆地鳄鱼是如何到达那里的呢？研究人员说，它们在这些岛屿上的存在是另一条线索，表明大约3200万至3500万年前，可能存在一条临时陆桥或一系列岛屿，允许陆地动物从南美洲前往加勒比海。
“The distance between the islands and northern South America was significantly shorter than what it is today. This likely facilitated the dispersal of sebecids from South America,” Viñola Lopez said. “This shows how important islands can be as a biodiversity museum, preserving the last members of some groups that have gone extinct everywhere.”
“这些岛屿与南美洲北方之间的距离比今天短得多。这可能促进了 sebecids 从南美洲的传播，”Viñola 洛佩斯说。“这表明岛屿作为生物多样性博物馆是多么重要，它保护了一些已经灭绝的群体的最后成员。”