Spiny chondrichthyan from the lower Silurian of South China
Spiny chondrichthyan from the lower Silurian of South China
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DOI：
10.1038/s41586-022-05233-8
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发表时间：
2022-09-29
期刊：
影响因子：
64.8
通讯作者：
Zhu, Min
中科院分区：
文献类型：
--
作者：
Andreev, Plamen S.;Sansom, Ivan J.;Zhu, Min
软骨鱼类（软骨鱼类）和硬骨鱼类（硬骨鱼和四足动物）的现代代表具有对比鲜明的骨骼解剖学和发育轨迹（1-4），强调了这两个分支的远距离进化分裂（5-7）。最近对上志留世和泥盆纪有颚脊椎动物的研究（7-10）揭示了相似的骨骼条件，模糊了硬骨鱼类、软骨鱼类和它们有颚颌类祖先之间的传统区别。本文描述了一种软骨鱼类化石--梵净山藻（Fanjingshania renovata gen. et sp. nov.）产于中国志留纪早期，早于有颌脊椎动物最早的关节化石（10-12）。梵净山虫具有真皮肩带板和鳍刺的补充，与茎软骨鱼类的一个亚群（climatiid 'acanthodians'（14））有着惊人的解剖学相似性。然而，在软骨鱼类中，它的独特之处在于，它表现出类似硬骨鱼的鳞齿突（真皮牙齿）的吸收脱落，并且其脊柱中缺乏牙源性组织。我们的研究结果确定了软骨藻茎组中这些条件的独立获得，将梵净山藻添加到越来越多的嵌套在传统定义的棘藻中的分类群中（7，15）。梵净山虫的发现为有颌脊椎动物在下泥盆统化石记录中广泛出现之前的早志留世辐射提供了最有力的支持。
Modern representatives of chondrichthyans (cartilaginous fishes) and osteichthyans (bony fishes and tetrapods) have contrasting skeletal anatomies and developmental trajectories(1-4) that underscore the distant evolutionary split(5-7 )of the two clades. Recent work on upper Silurian and Devonian jawed vertebrates(7-10) has revealed similar skeletal conditions that blur the conventional distinctions between osteichthyans, chondrichthyans and their jawed gnathostome ancestors. Here we describe the remains (dermal plates, scales and fin spines) of a chondrichthyan, Fanjingshania renovata gen. et sp. nov., from the lower Silurian of China that pre-date the earliest articulated fossils of jawed vertebrates(10-12). Fanjingshania possesses dermal shoulder girdle plates and a complement of fin spines that have a striking anatomical similarity to those recorded in a subset of stem chondrichthyans(5,7,13) (climatiid 'acanthodians'(14)). Uniquely among chondrichthyans, however, it demonstrates osteichthyan-like resorptive shedding of scale odontodes (dermal teeth) and an absence of odontogenic tissues in its spines. Our results identify independent acquisition of these conditions in the chondrichthyan stem group, adding Fanjingshania to an increasing number of taxa(7,15) nested within conventionally defined acanthodians(16). The discovery of Fanjingshania provides the strongest support yet for a proposed(7) early Silurian radiation of jawed vertebrates before their widespread appearance(5) in the fossil record in the Lower Devonian series.