生活了1亿2000万年的蚂蚁物种

生活了1亿2000万年的蚂蚁物种

新华网华盛顿９月１５日电（记者张忠霞）美国生物学家最近在巴西境内的亚马孙雨林发现了一种新蚂蚁，初步认定这可能是最古老蚂蚁的后代。由于这种蚂蚁有许多前所未见的特征，生物学家称之为“火星来的蚂蚁”。

来自得克萨斯大学的克里斯蒂安·拉伯尔等人在新一期美国《国家科学院学报》上介绍说，这种蚂蚁通体呈金黄色，在土壤中生存，体长２到３毫米，没有眼睛，但有很大的大颚。由于它是肉食性蚂蚁，拉伯尔等人猜测它的大颚是捕食的利器。

经过形态学和基因分析，拉伯尔等人将这种蚂蚁归入单独一个亚科。这是自１９２３年以来，科学家第一次发现隶属于新亚科的活蚂蚁，其他的新亚科蚂蚁都是以化石形式被发现的。目前已知的蚂蚁亚科共有２１个。

对这种蚂蚁腿部的ＤＮＡ（脱氧核糖核酸）分析结果显示，这种蚂蚁很可能是最古老蚂蚁家族的后裔，处于蚂蚁进化树的最初始阶段。

蚂蚁和黄蜂有着共同的祖先，大约在距今１．２亿年前，在进化道路上“分家”。蚂蚁的种类相当丰富，具有重要的生态学研究价值。拉伯尔说，这一新发现将有助于生物学家更好地理解蚂蚁的生物多样性和进化历程，“这种新蚂蚁的发现说明，可能还有很多新的蚂蚁种类，甚至是巨大的进化线索埋藏在热带雨林的土壤中”。
=========================以下是从wiki截取的内容


Martialis heureka, nicknamed the "Ant from Mars" due to its unusual features and heureka from its surprising discovery, is a new species of ant discovered in the Amazon rainforest near Manaus, Brazil. Two specimens were first discovered by Manfred Verhaagh of the Staatliches Museum für Naturkunde in Karlsruhe, Germany in 2000, but they became desiccated and were broken on their way to being tested, and so could not be verified as being a new species. It wasn't until another specimen was found in 2003 by Christian Rabeling, a graduate student of the University of Texas at Austin, that the discovery finally came to light.

Known only from these three specimens, the species is placed in a monotypic genus and a new subfamily (Martialinae) that is a sister lineage to all other living ants and which is the first extant ant subfamily to be discovered since 1923.

The ants themselves are eyeless, pale in color, subterranean, and predatory. This doesn't mean that the ancestor to all ants was blind and lived underground, but that these features evolved early in ant history and have persisted in the environmentally stable soils of the tropical rainforest. They possess unusual, elongated mandibles and are distinctly basal in their features. Like all basal ants, they possess a stinger. The species is significant in that its lineage appears to be particularly ancient and that they are likely the last surviving species of a line which diverged from other ants early in ant evolution. Genetic samples obtained from the specimen's leg seem to place the species' emergence at roughly 50 million years ago, and the emergence of its line at just after the time ants diverged from wasps, nearly 120 million years ago.

While it was originally believed that the first ants dwelled on the surface like wasps, the modern view is that they only came to the surface 125 million years ago, following the evolution of flowering plants.