Osteological and histological comparison of the development of the interphalangeal intercalary skeletal element between hyloid and ranoid anurans
Osteological and histological comparison of the development of the interphalangeal intercalary skeletal element between hyloid and ranoid anurans
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DOI：
10.1111/dgd.12844
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发表时间：
2023-02
期刊：
影响因子：
4.6
通讯作者：
Kensuke Nakanishi;Nao Hasegawa;Koichi Takeo;K. Nakajima;Nobuaki Furuno;I. Tazawa
中科院分区：
文献类型：
--
作者：
Kensuke Nakanishi;Nao Hasegawa;Koichi Takeo;K. Nakajima;Nobuaki Furuno;I. Tazawa
有些蛙类在所有指骨的末端和次末端指骨之间的关节处有一个独特的骨骼元件，称为骨间元件（IE）。IEs由软骨或结缔组织组成，其形状与指骨明显不同。IEs与树栖生活方式和脚趾垫密切相关。IE只在无尾目蛙类中的新蛙类中被发现，这表明它是新蛙类的一个新物种。IEs广泛分布于新巴塔亚系的多个分支中，在新巴塔亚系的两个主要分支Hyloides和Ranoides中都有发现。然而，目前尚不清楚在多个谱系中发现的ie是否是趋同进化的结果。因此，在本研究中，我们旨在研究Hyloides和Ranoides之间IEs发育轨迹的相似或不同程度。为此，我们比较了日本湿蛙（Dryophytes japonicus）和蛇形蛙（Zhangixalus schlegelii）的骨骼和组织学发育过程。当蝌蚪开始形成IE时，这两个物种共享相同的IE起始位点和IE周围的组织分化水平，尽管IE的发展开始于不同的阶段，这是由外部标准决定的。这些结果表明，在这两个物种的手指中，类似的机制驱动了IE的形成，支持了IE没有趋同进化的假设。
Some frog species have a unique skeletal element, referred to as the intercalary element (IE), in the joints between the terminal and subterminal phalanges of all digits. IEs are composed of cartilage or connective tissue and have a markedly differ shape than the phalanges. IEs are highly related to the arboreal lifestyle and toe pads. The IE is found only in neobatrachian frogs among anurans, suggesting that it is a novelty of Neobatrachia. IEs are widely distributed among multiple neobatrachian lineages and are found in the suborders Hyloides and Ranoides (the two major clades in Neobatrachia). However, it is unclear whether the IEs found in multiple linages resulted from convergent evolution. Therefore, in this study, we aimed to examine how similar or different the developmental trajectories of the IEs are between Hyloides and Ranoides. To that end, we compared the osteological and histological developmental processes of the IEs of the hyloid frog Dryophytes japonicus and the ranoid frog Zhangixalus schlegelii. Both species shared the same IE‐initiation site and level of tissue differentiation around the IE when it began to form in tadpoles, although the IE developments initiated at different stages which were determined by external criteria. These results suggest that similar mechanisms drive IE formation in the digits of both species, supporting the hypothesis that the IEs did not evolve convergently.