A unique winged euthycarcinoid from the Permian of Antarctica
A unique winged euthycarcinoid from the Permian of Antarctica
复制标题
来自南极洲二叠纪的一种独特的有翅类癌
DOI：
10.1017/jpa.2017.28
复制
发表时间：
2017
影响因子：
1.4
通讯作者：
Miller, Molly F.
中科院分区：
文献类型：
--
作者：
Collette, Joseph H.;Isbell, John L.;Miller, Molly F.
寒武纪-三叠纪的类癌节肢动物可能是最早从海洋过渡到淡水和新兴环境的动物。虽然它们的基本包氏体是众所周知的，但它们的化石记录很差，因为它们的非硬化外骨骼很少被保存下来。真类癌的异常形态（不同数目的体节，似乎二分拥有下颌骨或唇，专门或普遍的四肢，并拥有一些euthycarcinoid物种的胸骨孔-结构可能类似于基节囊在多足动物）有助于不确定性，关于他们的关系，其他节肢动物群体;而他们可怜的化石记录掩盖了他们居住的不同领域（海洋，淡水，新兴）内部和之间的进化过渡。一个新的euthycarcinoid从二叠纪极地冰前湖在这里描述的是形态上不同于所有其他euthycarcinoid，并解释为是很好地适应了游泳生物底栖生活方式。ticarcinus pagoda n.一般的;一般的具有一对大的翼状突起，从腹前背侧外骨骼向外突出。一个来自上覆Mackellar地层的遗迹化石，参见。Orbiculichnus以前被解释为是由昆虫起飞或降落在潮湿的沉积物上产生的，在这里被重新解释为是由A.宝塔;宝塔一般的;一般的sp.由于痕迹和身体化石之间的高度形态相似性。这种情况表明，euthycarcinoids能够适应生活在温带淡水环境中，而可能的陆上适应暗示了呼吸空气的能力。事实上，如果真类癌瘤能够呼吸空气，寒武纪的陆地入侵和（到奥陶纪）向淡水环境的快速过渡就可能得到解释。
Euthycarcinoid arthropods (Cambrian–Triassic) were likely the first animals to transition from oceanic to freshwater and emergent environments. Although their basic bauplan is well known, they have a poor fossil record because their non-sclerotized exoskeleton was rarely preserved. Euthycarcinoids’ unusual morphology (varying numbers of body segments, seemingly dichotomous possession of either mandibles or a labrum, specialized or generalized limbs, and possession by some euthycarcinoid species of sternal pores—structures possibly analogous to coxal vesicles in myriapods) contribute to uncertainty regarding their relationship to other arthropod groups; while their poor fossil record masks the evolutionary transitions within and between the separate realms they inhabited (marine, freshwater, emergent). A new euthycarcinoid from a Permian polar proglacial lake is described herein that is morphologically unlike all other euthycarcinoids, and interpreted as being well adapted for a nekton-benthic lifestyle. Antarcticarcinus pagoda n. gen. n. sp. possesses a pair of large wing-like processes that project laterally from the preabdominal dorsal exoskeleton. A trace fossil from the overlying Mackellar Formation, cf. Orbiculichnus, which was previously interpreted as having been produced by insects taking off or landing on wet sediments, is reinterpreted herein as being produced by A. pagoda n. gen. n. sp. due to the high degree of morphological similarity between traces and body fossils. This occurrence indicates that euthycarcinoids were able to adapt to life in temperate freshwater environments, while possible subaerial adaptations hint at an ability to breathe air. Indeed, if euthycarcinoids could breathe air, Cambrian terrestrial forays and rapid transition (by the Ordovician) into freshwater environments might be explained.