NEW ANATOMICAL INFORMATION ON ANOMALOCARIS FROM THE CAMBRIAN EMU BAY SHALE OF SOUTH AUSTRALIA AND A REASSESSMENT OF ITS INFERRED PREDATORY HABITS
NEW ANATOMICAL INFORMATION ON ANOMALOCARIS FROM THE CAMBRIAN EMU BAY SHALE OF SOUTH AUSTRALIA AND A REASSESSMENT OF ITS INFERRED PREDATORY HABITS
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DOI：
10.1111/pala.12029
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发表时间：
2013-09-01
期刊：
影响因子：
2.6
通讯作者：
Jago, James B.
中科院分区：
文献类型：
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作者：
Daley, Allison C.;Paterson, John R.;Jago, James B.
在袋鼠岛大峡谷的额木湾页岩(寒武纪系列2，阶段4)中，两种Anomalcaris共同出现。Briggsi Nedin，1995年的额部附属物比cf.加拿大白鹰，1892年，在这些物种最初被描述的波浪切割平台遗址内陆的采石场。一个口锥有三个大的，结节承托板，最近为加拿大Anomalcaris记录，证实Anomalcaris缺乏四个放射状Peytoia‘口锥，并加强了澳大利亚标本的身份为Anomalocis的情况。与其他地方相比，埃穆湾页岩中脱节的异常龋齿体瓣数量更多，它们保留了其他地方没有认识到的解剖细节。瓣前部的横线，在以前对异形线虫的描述中被解释为强化射线或静脉，与由一系列边界良好的条纹区块或条组成的内部结构有关。它们的结构与赋予身体襟翼力量的结构功能一致。由一系列披针形叶片组成的刚毛结构与其他异形吸虫的结构相似，可单独发现或与身体瓣相关。单个标本也保留了假定的肠道憩室。Anomalcaris的附肢、口锥、肠道憩室和复眼的形态及其巨大的体型表明，它是一种活跃的捕食者，含有三叶虫碎片的粪便标本和具有突出伤害的三叶虫标本被认为是异常吸食三叶虫的证据。根据额部附属物的形态，推测无尾无尾轮虫是软体动物的唯一捕食者，且仅为无尾无尾轮虫。尽管红藻的捕食(包括可能的自相残食)也可以解释在额木湾页岩中发现的粪便和对三叶虫外骨骼的破坏，但加拿大人可能能够对三叶虫进行强食性捕食。
Two species of Anomalocaris co-occur in the Emu Bay Shale (Cambrian Series 2, Stage 4) at Big Gully, Kangaroo Island. Frontal appendages of Anomalocaris briggsi Nedin, 1995, are more common than those of Anomalocaris cf. canadensis Whiteaves, 1892, at a quarry inland of the wave-cut platform site from which these species were originally described. An oral cone has the three large, node-bearing plates recently documented for Anomalocaris canadensis, confirming that Anomalocaris lacks a tetraradial Peytoia' oral cone and strengthening the case for the identity of the Australian specimens as Anomalocaris. Disarticulated anomalocaridid body flaps are more numerous in the Emu Bay Shale than in other localities, and they preserve anatomical details not recognized elsewhere. Transverse lines on the anterior part of the flaps, interpreted as strengthening rays or veins in previous descriptions of anomalocaridids, are associated with internal structures consisting of a series of well-bounded, striated blocks or bars. Their structure is consistent with a structural function imparting strength to the body flaps. Setal structures consisting of a series of lanceolate blades are similar to those of other anomalocaridids and are found in isolation or associated with body flaps. A single specimen also preserves putative gut diverticula. The morphology of the appendages, oral cone, gut diverticula and compound eyes of Anomalocaris, along with its large size, suggests that it was an active predator, and specimens of coprolites containing trilobite fragments and trilobites with prominent injuries have been cited as evidence of anomalocaridid predation on trilobites. Based on frontal appendage morphology, Anomalocaris briggsi is inferred to have been a predator of soft-bodied animals exclusively and only Anomalocaris cf. canadensis may have been capable of durophagous predation on trilobites, although predation (including possible cannibalism) by Redlichia could also explain the coprolites and damage to trilobite exoskeletons found in the Emu Bay Shale.