【作者】 李伟； 杨杰； 张喜光；

【Author】 LI Wei;YANG Jie;ZHANG Xiguang;Key Laboratory for Palaeobiology,Yunnan University;MEC International Joint Laboratory for Palaeoenvironment,Yunnan University;

【机构】 Key Laboratory for Palaeobiology,Yunnan University； MEC International Joint Laboratory for Palaeoenvironment,Yunnan University；

【摘要】 Omnidens amplus is a large feeding apparatus which is composed of oval plates,radially-arranged teeth and pharyngeal teeth,first documented from the Chengjiang Lagerst?tte.At first it was interpreted as the mouth of an affinity unknown anomalocaridid,and subsequently reinterpreted as the introvert of giant priapulan by being compared with extant priapulid Priapulus caudatus.Based on the evidence of the early Cambrian gilled lobopodian Pambdelurion whittingtoni from Sirius Passet,Greenland,it was recently interpreted as the mouthpart of an unrecognized giant Pambdelurion-like animal rather than an introvert of giant priapulan.The Xiaoshiba Lagerst?tte preserves a large number of such mouthpart fossils,which exhibiting exquisite morphological details have never been seriously investigated.Research on the mouthparts can offer illuminations to estimate their feeding behaviors when only the mouthparts are preserved,and provide direct clues to evaluate the essential body configuration and relationship between the intriguing Omnidens and Pambdelurion.The mouthparts found from the Xiaoshiba differ from the typical round mouth in that the teeth arranged on the mouth are no longer equal,but tend to gradually decrease from the middle to the ends.And the small teeth found at both ends provide a new reference model for the development of such a mouthpart.This mouthpart may no longer be ring-shaped,but consists of two parts.And there may be a mistake in the statement that the teeth of Omnidens and Pambdelurion are arranged in a ring shape.In addition the Xiaoshiba mouthparts are always associated with well-preserved sclerites,which,with large spines,were presumed as asymmetrically developed sclerites and regarded as the remains of an anomalocaridid.In a previous study the large and strongly sclerotized parts were explained as the only remain of a dead anomalocaridid which had been devoured by an Omnidens.However,additional evidence from our new material shows that the so-called sclerite is not only symmetrical in arrangement,but also represents the outermost part of tooth assemblage constituting the moutpart,to assist in grasping and shredding the prey.In comparison the plate of the sclerite is similar to the triangular plates of the mouthparts.The confusing in previous studies have led to a misunderstanding about this basic structure which was mistaken as the remains of an anomalocaridid because the preserved orientation is lateral rather than dorsoventral.Based on the mouthparts seen from the Xiaoshiba material.we propose a new tooth arrangement for the Omnidens-like mouthparts.更多还原

【Abstract】 Omnidens amplus is a large feeding apparatus which is composed of oval plates,radially-arranged teeth and pharyngeal teeth,first documented from the Chengjiang Lagerst?tte.At first it was interpreted as the mouth of an affinity unknown anomalocaridid,and subsequently reinterpreted as the introvert of giant priapulan by being compared with extant priapulid Priapulus caudatus.Based on the evidence of the early Cambrian gilled lobopodian Pambdelurion whittingtoni from Sirius Passet,Greenland,it was recently interpreted as the mouthpart of an unrecognized giant Pambdelurion-like animal rather than an introvert of giant priapulan.The Xiaoshiba Lagerst?tte preserves a large number of such mouthpart fossils,which exhibiting exquisite morphological details have never been seriously investigated.Research on the mouthparts can offer illuminations to estimate their feeding behaviors when only the mouthparts are preserved,and provide direct clues to evaluate the essential body configuration and relationship between the intriguing Omnidens and Pambdelurion.The mouthparts found from the Xiaoshiba differ from the typical round mouth in that the teeth arranged on the mouth are no longer equal,but tend to gradually decrease from the middle to the ends.And the small teeth found at both ends provide a new reference model for the development of such a mouthpart.This mouthpart may no longer be ring-shaped,but consists of two parts.And there may be a mistake in the statement that the teeth of Omnidens and Pambdelurion are arranged in a ring shape.In addition the Xiaoshiba mouthparts are always associated with well-preserved sclerites,which,with large spines,were presumed as asymmetrically developed sclerites and regarded as the remains of an anomalocaridid.In a previous study the large and strongly sclerotized parts were explained as the only remain of a dead anomalocaridid which had been devoured by an Omnidens.However,additional evidence from our new material shows that the so-called sclerite is not only symmetrical in arrangement,but also represents the outermost part of tooth assemblage constituting the moutpart,to assist in grasping and shredding the prey.In comparison the plate of the sclerite is similar to the triangular plates of the mouthparts.The confusing in previous studies have led to a misunderstanding about this basic structure which was mistaken as the remains of an anomalocaridid because the preserved orientation is lateral rather than dorsoventral.Based on the mouthparts seen from the Xiaoshiba material.we propose a new tooth arrangement for the Omnidens-like mouthparts.更多还原