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当前位置: Science » 植物&动物 » Science:古“塔利怪物”终于在生命之树上获得了一席之地


摘要 : 在古生物边缘徘徊了近60年后,生活在3亿年前的一种形状古怪的软体海洋生物终于在生命族谱上获得了一席之地。


 在古生物边缘徘徊了近60年后,生活在3亿年前的一种形状古怪的软体海洋生物终于在生命族谱上获得了一席之地。1958年,这个新物种(Tullimonstrum gregarium)的首个标本被业余的化石猎人所发现,此后它便被非正式地称为“塔利怪物”。它只是外观像个怪物(上图为艺术家的概念图),最大的个体约有15厘米长。尽管在伊利诺伊州北部某地的煤矿里出土了数以千计的该物种的化石——该地区的岩石生成于距今3.7亿至3.9亿年前,但在世界其他地方都没有类似发现,这也是塔利怪物在1989年被命名为伊利诺伊州化石的一个原因。研究人员今日在《自然》杂志网络版上报告称,一项针对1200多个化石的详细分析从多个角度阐述了该生物残骸,确认了它和七鳃鳗这种类鳗生物的关系。尽管塔利怪物的形状和现存或已灭绝的七鳃鳗没有任何相似之处,新的研究仍首次揭示了这种生物长有鳃和一个被称为脊索的灵活的像脊椎骨的杆状物——这些解剖学特征使得该生物像今天的七鳃鳗一样被归为脊椎动物。研究人员提出,塔利怪物的眼睛离身体很远,分别在另一个灵活的脊索的两端,这帮助它在靠近长有牙齿的长鼻的末端获得猎物的三维图像。比起当代的七鳃鳗通常所做的蛇形游动,塔利怪物可能通过尾巴上的肌肉发达的组织边缘的波动来推动自身前进,类似于今天乌贼的游动方式。


Ancient ‘Tully Monster’ finally gets its place on tree of life


After nearly 6 decades in paleontological limbo, a weirdly shaped, soft-bodied sea creature that lived more than 300 million years ago has gained a spot on life’s family tree. Tullimonstrum gregarium, informally dubbed the “Tully Monster” after the amateur fossil hunter who discovered the first specimens in 1958, is monstrous only in terms of its appearance (artist’s concept above), with the largest individuals measuring in at about 15 centimeters long. Although unearthed by the thousands in the coal pits at one site in northeastern Illinois, wher rocks were laid down between 307 million and 309 million years ago, its fossils have been found nowher else in the world—one reason the Tully Monster was named Illinois’s state fossil in 1989. Now, a detailed analysis of more than 1200 fossils that provide views of the creature’s remains from many angles confirm its relation to the eellike creatures known as lampreys, the researchers report online today inNature. Even though the Tully Monster was shaped like no other lamprey living or extinct, the new study reveals for the first time that the creature had gills and a flexible backbonelike rod called a notochord—anatomical features that make the creature, like today’s lampreys, a vertebrate.Tullimonstrum’s eyes sat far from the body at the ends of another flexible rod, which helped it get a 3D view of prey near the end of its tooth-sporting proboscis, the researchers propose. Rather than swimming with a snakelike motion, as modern-day lampreys typically do, the Tully Monster likely propelled itself with undulations of a muscular fringe of tissue on its tail, similar to the way that cuttlefish swim today.

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