The earliest known Spongeliomorpha from the Lower Devonian of the northwestern Yangtze Platform, South China
The earliest known Spongeliomorpha from the Lower Devonian of the northwestern Yangtze Platform, South China
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已知最早的海绵动物，产于华南扬子地台西北部下泥盆统
DOI：
10.1016/j.palaeo.2020.109772
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发表时间：
2020-08-01
影响因子：
3
通讯作者：
Xu，Honghe
中科院分区：
文献类型：
--
作者：
Zhang，Xiaole;Liu，Jianbo;Xu，Honghe
甲壳动物遗迹化石为地球历史中的古生物学、环境学和生态学解释提供了宝贵的信息。在这里，我们报告了一个异常大（段达58毫米宽），三维洞穴系统，从下泥盆统平邑铺组，这是沉积在近岸设置在扬子地台西北部，中国南方。洞穴系统主要由水平发育的网络组成，可能有垂直的竖井连接到沉积物-水界面。洞穴表面没有衬里的迹象，但其特征是划痕，包括脊和耳状条纹束，这意味着分配到Spongeliomorphaaff.S. chevronensis（Muñiz and Mayoral 2001）.整体形态和埋藏特征表明，永久性的，开放的洞穴，在相当坚固的基板上生产。进一步的调查表明，洞穴系统可能是由一群大型、未知的甲壳类动物构成的，其胸部附属物装饰有尖锐的刚毛或锯齿。它们通常起到一个共同的作用，即栖息在隧道边缘，也许还以积聚在隧道边缘的微生物生长为食。这些洞穴代表了最早的三维洞穴系统的甲壳类动物，可能是他们的现代类似物在形态和功能方面。洞穴的异常大的尺寸可能是在泥盆纪早期受到较高的大气氧气水平的青睐。
Crustacean trace fossils provide invaluable information to paleobilogical, environmental and ecological interpretations in the Earth history. Here we report an unusually large (segments up to 58 mm across), three-dimensional burrow system from the Lower Devonian Pingyipu Formation, which was deposited in a nearshore setting on the northwestern Yangtze Platform, South China. The burrow system is dominated by horizontally-developed networks probably with vertical shafts connecting to the sediment-water interface. The burrow surfaces show no signs of lining but are characterized by scratches including ridges and bundles of ear-shaped striae, implying an assignation toSpongeliomorphaaff.S. chevronensis(Muñiz and Mayoral 2001). The overall morphological and taphonomic features suggest permanent, open burrows, produced in a substrate with considerable firmness. Further investigation indicates that the burrow system may have been constructed by a colony of large, unknown crustacean with thoracic appendages decorated with acute seta or denticulations. They generally served a combined purpose of dwelling and perhaps feeding on microbial growth accumulating on the tunnel margins. These burrows represent the earliest known three-dimensional burrow systems constructed by a crustacean that may be comparable to their modern analogues in both morphological and functional aspects. The unusually large size of the burrows may have been favored by a higher atmospheric oxygen level during the Early Devonian.