古生物探奇：在3厘米长的琥珀中找到了迄今最小的恐龙颅骨_风闻

【来源龙腾网】

正文原创翻译：

本文作者为朴茨茅斯大学古生物学教授大卫·马提尔

2020年3月11日

The head of a flying dinosaur that is hardly bigger than a bee hummingbird has been discovered in 99-million-year-old amber. The piece of polished amber, just 31mm by 20mm by 8.5mm, was found in Kachin Province of northern Myanmar, an area becoming increasingly well-known for its remarkable amber-encased fossils.

一种飞行恐龙的头部被发现于有9900万年历史的琥珀中，体积几乎还没有一只蜂鸟大。这块圆滑发亮的琥珀大小只有31毫米ⅹ20毫ⅹ8.5毫米，发现于缅甸北部的克钦邦，该地区因其不同寻常的、包裹于琥珀中的化石而越来越为世人所知。

（译注：克钦邦是缅甸北部的自治邦，首都在密支那，与云南省接壤，克钦族与我国景颇族为同一民族，曾为南诏国/大理国领土）

This exciting little fossil micro-dinosaur named Oculudentavis khaungraae is from the middle of the Cretaceous period, from a stage known as the Cenomanian. The skull looks remarkably bird-like and a number of features suggest Oculudentavis is related to the early ancestors of modern birds. The fossil also appears to have preserved some of the dinosaur’s original bodily material.

这种令人兴奋的微型恐龙化石被命名为Oculudentavis khaungraae（宽娅眼齿鸟），来自白垩纪中期，来自一个称为森诺曼的阶。该具颅骨看上去惊人地像鸟，而且还有很多特征能表明宽娅眼齿鸟与现代鸟类的早期祖先有亲缘关系。这块化石看起来也保存了该恐龙的一部分身体物质。

（译注：属名眼齿体现出最鲜明的两大特点,即硕大的眼睛和密集的牙齿；森诺曼阶（Cenomanian）是地质年代中上白垩统最下的一阶。在时间上它位于阿尔布阶（下白垩纪）和土仑阶之间）

The researchers from China and the US who studied the fossil subjected it to CT analysis (computed tomography, which uses X-rays to produce a series of cross-section images of a specimen) to examine the internal structure. But the amber is sufficiently clear that many of the features can be seen with the naked eye and a hand lens.

研究该化石的中国和美国研究者对其作了CT分析（计算机断层扫描，也就是用X光来生成样本的一系列横截面图像），以检视其内部结构。但这块琥珀足够清晰，很多特征用肉眼加一幅放大镜就可以看清。

Oculudentavis has a long slender beak, a mouthful of needle-sharp teeth and massive eyes. Unlike most fossils, in which the original material is replaced by other minerals, the skull still appears to be composed of actual bone, although its microstructure and possible cell content have yet to be analysed.

宽娅眼齿鸟有着长而尖细的喙，满嘴尖利的牙齿以及硕大的眼睛。和大部分化石不同，它们原本的物质会被其他矿物置换掉，看起来这具颅骨仍是由真正的骨骼组成的，虽然它的微观结构以及可能的细胞内含物还没有经过分析。

 

（图解：宽娅眼齿鸟的艺术效果图）

Some of the skin of the palate and the tongue is also preserved, including the small pointed papillae on its surface. In modern passerine birds such as the the robin, these tongue bumps are directed backwards and prevent prey escaping from the mouth.

上颚和舌头部位的一部分皮肤也保存了下来，包括其表面上细小的乳头状突起。在诸如知更鸟的现代雀形目鸟类中，这些舌上凸起是倒着长的，以防猎物从嘴里逃脱。

There do not appear to be any feathers preserved, but some of the organic material decayed to produce what is now a yucky mess (who would think that such things could be fossilised?) Sadly the rest of the animal’s body is not preserved. Perhaps it exists in another amber fragment awaiting discovery.

似乎并没有保存下来任何羽毛，但有一部分腐烂的（身体）组织物质，到现在成了一堆恶心的乱糟糟的玩意儿（谁能想到这种东西都可以变成化石？）遗憾的是，这只动物的其他身体部分没有保存下来。也许存在于另一块等着人们发现的琥珀碎片中。

原创翻译：龙腾网 http://www.ltaaa.com 翻译：yzy86 转载请注明出处

One particularly revealing feature is the skull’s huge orbit (eye socket). A circle of tiny bony plates known as a sclerotic ring is arranged within the orbit, forming a cone with an inner circle that indicates the creature would have had a very small pupil. This kind of eye is typical of many lizards of today that are active during the day and sleep at night, suggesting that Oculudentavis had a similar “diurnal” schedule.

存在一个特别能透露信息的特征，就是颅骨上的硕大眼眶。被称为“巩膜环”的小小的一圈骨板排列在眼眶之内，构成了一个圆锥形并带有一个内圈，这就表明这种生灵的瞳孔是非常非常小的。这种眼睛是典型的现今很多昼出夜伏的蜥蜴会拥有的那种眼睛，这就表明：与前者类似地，宽娅眼齿鸟也会在“白天”活动。

（译注：巩膜环（scleral ring）为眼球外部有一层坚硬的骨质结构，也叫巩膜骨，用来保护和支持眼球，哺乳动物和鳄类中均不具有巩膜环结构）

Significant find

重大发现

The discovery is incredibly exciting for a number of reasons. Without a doubt this is a dinosaur, but one that sits on the early part of the evolutionary tree that leads to modern birds. In fact, the authors’ analysis suggests that it is quite close to the most famous of all bird-dinosaurs, Archaeopteryx, which dates to the earlier Late Jurassic period around 150 million years ago and has been called the first bird.

出于很多原因，这项发现极为振奋人心。毫无疑问这是一种恐龙，但它是一种在演化为现代鸟类的进化树上位居早期阶段的恐龙。事实上，这些作者的分析表明：它相当接近最有名的鸟龙——始祖鸟，后者可以追溯到年代更早的侏罗纪晚期，约1.5亿年前，已经被称为史上第一只鸟。

Oculudentavis is also incredibly small. In fact, with a skull just 15 millimetres long, it must rank as the smallest of any dinosaur. While it is not certainly adult, it is by no means a juvenile, meaning it probably wouldn’t have grown much bigger.

而且，宽娅眼齿鸟小到了让人难以置信的地步。事实上，其颅骨只有15毫米长，它一定会被列为最小的恐龙。虽然它不一定是成体，但它绝不可能是亚成体，这就意味着它的个头可能长不到更大了。

The researchers point out that animals that evolve to become much smaller tend to come from isolated environments such as islands. For examples, there were once dwarf mammoths on Crete, Sardinia and Cyprus. Coincidentally, geologists have suggested that the Myanmar amber deposits were formed on an island that was part of a volcanic arc on the margins of the ancient Thethys Ocean.

研究者指出，那些在进化中变得小得多的动物往往来自隔绝的环境，比如岛屿。举例来说，在克里特岛、撒丁岛和塞浦路斯，一度存在过侏儒猛犸象。巧合的是，已经有地理学家们认为缅甸的琥珀矿床是形成于一个岛屿上的，后者是位于古特提斯海边缘的火山岛弧的一部分。  

（译注：特提斯海是位于北方劳亚古陆和南方冈瓦纳古陆之间的古海洋，现代地中海是特提斯海的残留海域）

The discovery of Oculudentavis is all the more fascinating because it was found in amber. Almost all fossils are formed from the hard remains of animals and plants: bones, teeth, shells and wood. But the amber has preserved some of the soft tissues of the dinosaur, making it a very unlikely fossil.

宽娅眼齿鸟的发现是更为迷人的，因为它被发现于琥珀之中。几乎所有的化石都是由动物和植物的硬质遗骸形成的：骨骼、牙齿、甲壳以及木头。但这块琥珀把这只恐龙的一部分软组织保存下来了，这就使其成为了一件不太可能出现的化石。

 

（图解：琥珀化石）

Amber starts off as a sticky liquid resin oozing from wounds on trees. But as volatile chemicals evaporate from its surface, the resin hardens into lumps that take some hammering to remove from the tree. This means it is even more unlikely that a dinosaur would get preserved amber as most dinosaurs are large and the largest piece of amber ever discovered weighs a mere 15kg.

琥珀一开始是一种带粘性的液态树脂，是从树的伤口中渗出来的。但是随着带有挥发性的化学物质从其表面蒸发出去，这些树脂硬化，成为了团块，需要反复敲打才能将其从树上除去。这就意味着，恐龙保存在琥珀之中就更不可能了，因为大部分的恐龙体型很大，而迄今发现的最大的一块琥珀，重量只有15公斤。

 原创翻译：龙腾网 http://www.ltaaa.com 翻译：yzy86 转载请注明出处

Not even Michael Crichton, the author of Jurassic Park, could conceive of a dinosaur in amber. Instead his fairy-tale quest to resurrect dinosaurs envisaged a blood-sucking mosquito with a belly full of dino blood and dino DNA becoming trapped in the sticky resin.

甚至连《侏罗纪公园》的创作者迈克尔·克里顿都构想不出琥珀中的恐龙。在他的大片中寻求复活恐龙时，他的设想反而是一只吸血的蚊子，肚子里装满了恐龙血，而恐龙的DNA留存在这种粘性的树脂中。

But not all dinosaurs were large, and one hapless Oculudentavis khaungraae, the smallest of them all, found itself in the wrong place at the wrong time in a forest in what is now Myanmar. We do not know if this little dinosaur had wings and flew into the resin, or if it became accidentally stuck (presumably by its feathers) while hopping through the branches of a resiniferous tree.

但并非所有的恐龙体型都很大，而一只倒霉的宽娅眼齿鸟（是它们中间体型最小的）在错误的时间，让自己置身于在今天是缅甸的一片森林中的错误地点。我们不清楚这只小恐龙是否有翅膀，是否飞进了这团树脂之中，或是跳跃着穿过一颗能产生树脂的树时一不小心被树枝卡住（很可能是卡住了它的羽毛）了。

 

（图解：Oculudentavis颅骨的CT扫描图）

The fossilised remains of Oculudentavis will be rich in all sorts of chemical decay products that can often be traced back to original biomolecules. But unfortunately it is doubtful that any DNA remains. DNA is such a delicate molecule that it rarely survives more than a few thousand years in humans, perhaps as much as 17,000 years in other animals and just maybe around a million years in fossilised bacteria.

这些宽娅眼齿鸟的化石残骸会富含各种各样的经化学分解的产物，后者经常可以追溯到原始的生物分子。但不幸的是，是否还能留下DNA是存疑的。DNA是如此脆弱的一种分子，在人类中罕有能存活超过几千年的，或许在其他动物中能存活长达17000年，在已成为化石的细菌中能存活一百万年上下。

Oculudentavis actually isn’t the first dinosaur to be found in amber. In 2016, researchers reported a piece of amber also from Myanmar with the tail of feathered dinosaur. The authors of this paper speculated that one day a complete dinosaur might be found in amber. Well, we now have a head and a tail. It’s just a body that is missing.

事实上，宽娅眼齿鸟并不是第一种发现于琥珀中的恐龙。2016年时，研究人员上报了一块琥珀，它也产自缅甸，内含有羽毛恐龙的尾巴。据这篇论文的作者推测，有朝一日，可能会在琥珀中发现一只完整的恐龙。好吧，我们现在有了个头，有了个尾。只缺个身子了。

My hope though is for a pterodactyl to be found in amber. I don’t care how big or how small it is – I just want to know what they really looked like.

但我的希望是，能在琥珀中找到一只翼手龙。我不在乎它有多大多小，我只想知道它们的真身是个什么模样。