这种微小的海藻化石已经有10亿年的历史，是所有陆地植物祖先的亲戚

这种微小的海藻化石已经有10亿年的历史，是所有陆地植物祖先的亲戚

Around 450 million years ago one of the most important developments in the history of Earth occurred: plants colonized the land for the first time. Now a fossil has been found that could resemble the first species that developed this capacity, from which all modern land plants descend. Most remarkably, the fossil comes not from around the time of this epic event, but from more than twice as long ago.

大约4亿5千万年前，地球历史上最重要的发展之一发生了:植物第一次在陆地上殖民。现在，人们发现了一块化石，它可能类似于第一个发展出这种能力的物种，所有现代陆生植物都起源于这种能力。最引人注目的是，这块化石并不是来自这一重大事件前后，而是来自两倍多以前。

Professor Shuhai Xiao of Virginia Tech announced the discovery of fossilized green seaweed in billion-year-old ocean sedimentary rocks from Liaoning Province, north-eastern China, in Nature Ecology and Evolution under the name Proterocladus antiquus. P. antiquus exceeds the previous record for green seaweed by some 200 million years.

弗吉尼亚理工大学的肖树海教授在《自然、生态与进化》杂志上发表文章称，他在中国东北辽宁省10亿年前的海洋沉积岩中发现了绿色海藻化石。安帝古藻的数量比之前的记录多了2亿年。

Stephen Luntz

Like many paleobotanists, Xiao thinks all land plants evolved from green seaweeds, which continue to compete in the oceans with brown and red seaweeds, both of which failed to make the same transition to land. However, he acknowledged in a statement, "Not everyone agrees with us; some scientists think that green plants started in rivers and lakes, and then conquered the ocean and land later.”

和许多古植物学家一样，肖认为所有的陆生植物都是由绿色的海藻进化而来，而绿色的海藻在海洋中与棕色和红色的海藻竞争，而这两种海藻都没有向陆地过渡。然而，他在一份声明中承认，“并非所有人都同意我们的观点;一些科学家认为绿色植物起源于河流和湖泊，后来征服了海洋和陆地。”

Dr Qing Tang, who brought the fossils to Xioa's attention noted, “These seaweeds display multiple branches, upright growths, and specialized cells known as akinetes that are very common in this type of fossil.”

引起了肖教授注意的Qing Tang博士指出:“这些海藻显示出多种分枝，直立生长，以及一种特殊的细胞，即秋刀藻，在这类化石中很常见。”

The fossil dates back 1 billion years, and was captured using a microscope because it is only 2mm long, the size of a flea. Virginia Tech

As a forerunner of the tallest redwood or the extraordinary expanse of quaking aspen, Xiao's fossils are underwhelming, being just 2 millimeters (0.08 inches) long. Proverbs about mighty oaks and tiny acorns are underselling the truth.

作为世界上最高的红杉树的先驱者，或者是颤杨的非凡广布，肖的化石令人印象深刻，只有2毫米(0.08英寸)长。关于强大的橡树和微小的橡子的谚语低估了真理。

Some of P. antiquus' descendants, however, appear to go by the principle that when you are on to a good thing, stick to it.

然而，安帝古斯的一些后代似乎遵循这样的原则:当你想要做一件好事时，就要坚持下去。

“There are some modern green seaweeds that look very similar to the fossils that we found,” Xiao said. “A group of modern green seaweeds, known as siphonocladaleans, are particularly similar in shape and size to the fossils we found.” Intriguingly, P. antiquus bears considerable similarity to the next oldest fossil of this type, P. major, which has been found in 800 million-year-old rocks at Svalbard. The P. major fossils were less well preserved, however, making confirmation they are the same species difficult, and boosting hopes we will learn a lot more from the new find.

“有一些现代的绿色海藻，看起来和我们发现的化石非常相似，”肖说。“一群现代的绿色海藻，被称为吸虫藻，在形状和大小上与我们发现的化石特别相似。有趣的是，安帝古猿与这种类型的第二古老化石P. major极为相似，后者是在斯瓦尔巴特群岛8亿年前的岩石中发现的。然而，P.主要化石保存的不那么完好，这使得确认它们是同一物种变得困难，也增加了我们从新发现中获得更多信息的希望。

Red seaweeds fossils date back 1.05 billion years ago, but previously no green seaweeds had been found of similar ages. Molecular clocks suggest the first green photosynthesizing plants appeared somewhere between 1,600 and 720 million years ago, but scientists find such a wide range unsatisfying and hope fossil discoveries will narrow it down.

红色海藻的化石可以追溯到10.5亿年前，但是在此之前，还没有发现过与之年龄相近的绿色海藻。分子钟显示，最早的绿色光合植物出现在16亿到7亿2千万年前，但科学家们发现如此广泛的范围并不令人满意，希望化石的发现能缩小范围。

The discovery raises the question of why green seaweeds took so long to move onto dry land, given the speed with which they adapted to most environments once they did.

这一发现提出了一个问题:考虑到绿色海藻一旦适应大多数环境的速度，它们为什么要花这么长时间才能迁移到干燥的陆地上呢?