小柯机器人

中国科学院古脊椎动物与古人类研究所朱敏、瑞典乌普萨拉大学Per E. Ahlberg等研究人员合作报道中国早志留世最古老的完整有颌脊椎动物。该研究于2022年9月28日发表于国际一流学术期刊《自然》。

研究人员了一个新发现的Konservat-Lagerstätte，其特点是在华南重庆的早志留纪（泰利奇时代，约4.36亿年前）发现了多种多样的、保存完好的有颌鱼类的完整身体。我们将其命名为“Xiushanosteus mirabilis gen. et sp. nov.（奇迹秀山鱼）”，该物种是一种“盾皮鱼”或有颌类，结合了主要盾皮鱼亚群的特征。软骨鱼类Shenacanthus vermiformis gen. et sp. nov.（蠕纹沈氏棘鱼）表现出广泛的胸甲板，这在该系中以前是未知的，包括一个大的中间背板，如在腹足动物中，并结合传统的软骨鱼类结构。这些物种共同揭示了早志留纪有颌脊椎动物前所未有的多样性，并对这一时期有颌脊椎动物的全身形态提供了详细的见解。

据了解，分子研究表明，有颌脊椎动物的起源不晚于晚奥陶纪时期（约4.5亿年前）。这些分析与奥陶纪和早志留纪的软骨鱼类残骸一起，表明在奥陶纪末期大灭绝之前和之后，有颌脊椎动物的进化出现了扩散。然而，到目前为止，最早的完整的有颌鱼类化石（可以对其形态进行详细的重建）来自晚志留纪的组合（大约4.25亿年前）。由于缺乏晚志留世之前的有关节的全身化石，长期以来，有颌脊椎动物的最早历史变得模糊不清。

附：英文原文

Title: The oldest complete jawed vertebrates from the early Silurian of China

Author: Zhu, You-an, Li, Qiang, Lu, Jing, Chen, Yang, Wang, Jianhua, Gai, Zhikun, Zhao, Wenjin, Wei, Guangbiao, Yu, Yilun, Ahlberg, Per E., Zhu, Min

Issue&Volume: 2022-09-28

Abstract: Molecular studies suggest that the origin of jawed vertebrates was no later than the Late Ordovician period (around 450million years ago (Ma))1,2. Together with disarticulated micro-remains of putative chondrichthyans from the Ordovician and early Silurian period3,4,5,6,7,8, these analyses suggest an evolutionary proliferation of jawed vertebrates before, and immediately after, the end-Ordovician mass extinction. However, until now, the earliest complete fossils of jawed fishes for which a detailed reconstruction of their morphology was possible came from late Silurian assemblages (about 425Ma)9,10,11,12,13. The dearth of articulated, whole-body fossils from before the late Silurian has long rendered the earliest history of jawed vertebrates obscure. Here we report a newly discovered Konservat-Lagersttte, which is marked by the presence of diverse, well-preserved jawed fishes with complete bodies, from the early Silurian (Telychian age, around 436Ma) of Chongqing, South China. The dominant species, a ‘placoderm’ or jawed stem gnathostome, which we name Xiushanosteus mirabilis gen. et sp. nov., combines characters from major placoderm subgroups14,15,16,17 and foreshadows the transformation of the skull roof pattern from the placoderm to the osteichthyan condition10. The chondrichthyan Shenacanthus vermiformis gen. et sp. nov. exhibits extensive thoracic armour plates that were previously unknown in this lineage, and include a large median dorsal plate as in placoderms14,15,16, combined with a conventional chondrichthyan bauplan18,19. Together, these species reveal a previously unseen diversification of jawed vertebrates in the early Silurian, and provide detailed insights into the whole-body morphology of the jawed vertebrates of this period.

DOI: 10.1038/s41586-022-05136-8

Source: https://www.nature.com/articles/s41586-022-05136-8

Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
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