埃迪卡拉纪末期管状动物的“大辐射”

"Tubular animal radiation"at the terminal Ediacaran stage

“寒武纪大爆发”是生物演化史上最重要的事件之一,现生动物的绝大多数门类在短短的两千万年的时间里“突然”出现,这一事件奠定了显生宙生物演化的基础。普遍认为以软躯体为代表的埃迪卡拉生物群是生命进化中“失败”的尝试,与显生宙生物之间没有明确的亲缘关系。文中通过对新元古代管状化石记录的系统梳理,基于对高家山生物群中大量管状动物化石类群如Cloudina,Sinotubulites,Conotubus,Gaojiashania,Shaanxilithes及可能的Anabarites等的较为系统的厘定和形态学复原,提出在埃迪卡拉纪,与典型埃迪卡拉软躯体生物群演化相对应,在新元古代末期,早期动物的进化史上存在着管状动物的大辐射,它们形态复杂,生物构型多样,个体大小差异悬殊,生活方式繁杂,代表了地球生命史上一次重大的生物革新事件,并且其中部分生物成为寒武演化生物群的先驱。该文将这一辐射演化事件称为管状动物的“大辐射”,它开启了显生宙生命演化的序幕。

"Cambrian Explosion"is one of the most important events in the history of biological evolution,unparalleled diverse fossil fauna appeared abruptly in an interval not more than 20 million years at the beginning of the Cambrian.This event laid the foundation for the evolution of Phanerozoic organisms.It is generally accepted that the soft-bodied Ediacara biota is a"failed"experiment at the evolution of life,and there is no clear genetic relationship with the Phanerozoic organisms.Based on a comprehensive review of Neoproterozoic tubular fossil records,especialy on a more systematic identification and morphological restoration of a large number of tubular animal fossils in the Gaojiashan biota such as Cloudina,Sinotubulites,Conotubus,Gaojiashania,Shaanxilithes,and possibly Anabarites.It is proposed that in the Ediacaran Period,corresponding to the evolution of the typical Ediacaran soft-bodied biota,there was a large radiation of tubular animals in the evolutionary history of early lifes at the end of late Neoproterozoic.They are complex in morpho-types,diverse in bodyplans,varied in sizes and lifestyles,representing a major biological innovation in Earth′s life,some of which have been pioneers of the Cambrian Evolutionary Fauna.In this paper,the biodivercification event is called the"Tubular animal radiation",which opens the prologue of the evolution of Phanerozoic life.