ABSTRACT

The Carboniferous is characterized by drastic climatic and environmental fluctuations, which include multiple phases of glaciation resulting in an icehouse climate. Additionally, dynamic continental reconfigurations forced the contraction of the Rheic Ocean resulting in the closure of the Rheic–Tethyan Gateway, which precluded further faunal exchanges between the North American and Eurasian marine realms. Interestingly, cartilaginous fishes seem to be relatively immune to these drastic climatic and environmental changes. The Eurasian fossil record of Paleozoic sharks is strongly biased towards intensively sampled localities from England, Ireland, Scotland, and the Russian Platform. Here we present rare dental material from the Serpukhovian (early Carboniferous) of Austria, adding new information to the paleogeographic distribution of ctenacanthiform sharks. The new material revealed the first record of the genus Saivodus in Central Europe and allowed us to recognize a new species, Cladodus gailensis sp. nov., and a remnant of fossilized cartilage. In an attempt to identify possible linkages between climatic or environmental fluctuations on shark diversity throughout the Carboniferous, we provide a synopsis of the distribution and diversity of elasmobranchs based on primary literature. This preliminary assessment at genus level indicates two pronounced events of extinction, with the first one occurring during the latest Mississippian and the second one towards the end of the Pennsylvanian. The first extinction event distinctly correlates with the known diversity decline of other marine inhabitants and the second occurred during an unstable period of multiple phases of glaciation.

摘要

石炭纪的特点是剧烈的气候和环境波动，其中包括导致冰库气候的多个冰川期。此外，动态大陆重构迫使莱克洋收缩，导致莱克-特提斯门户关闭，从而阻止了北美和欧亚海洋领域之间的进一步动物群交流。有趣的是，软骨鱼类似乎对这些剧烈的气候和环境变化具有相对免疫力。欧亚古生代鲨鱼的化石记录强烈偏向于来自英格兰、爱尔兰、苏格兰和俄罗斯地台的密集采样地点。在这里，我们展示了来自奥地利 Serpukhovian（早石炭纪）的稀有牙科材料，为栉角鲨的古地理分布添加新信息。新材料揭示了该属的第一个记录Saivodus在中欧，并让我们认识了一个新物种Cladodus gailensis sp。11 月，还有一块化石软骨的残余物。为了确定整个石炭纪鲨鱼多​​样性的气候或环境波动之间可能存在的联系，我们提供了基于原始文献的棘鳃类动物分布和多样性的概要。这一属级的初步评估表明有两个明显的灭绝事件，第一个发生在最近的密西西比纪，第二个发生在宾夕法尼亚纪的末期。第一次灭绝事件与已知的其他海洋居民的多样性下降明显相关，第二次发生在冰川期多个阶段的不稳定时期。