"Tubular animal radiation"at the terminal Ediacaran stage

Abstract

Cambrian Explosionis 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 afailedexperiment 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 theTubular animal radiation,which opens the prologue of the evolution of Phanerozoic life.