Phylogenetic classification and evolution of Early Triassic conodonts
Phylogenetic classification and evolution of Early Triassic conodonts
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DOI：
10.1016/j.palaeo.2021.110731
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发表时间：
2021-10
期刊：
影响因子：
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通讯作者：
Ruoyu Bai;Haijun Song;M. Benton;L. Tian
中科院分区：
文献类型：
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作者：
Ruoyu Bai;Haijun Song;M. Benton;L. Tian
牙形刺是古生代和三叠纪最重要的生物地层标志化石之一，因其演化迅速、分布广泛而备受关注。在这里，我们提出了一个分支分析的早三叠世牙形刺的系统分类和进化关系的三个相关的家庭的系统分类，Ellisonidae，和Gondolellidae。通过对73个离散形态特征（40个P1元特征、4个P2元特征、27个S元特征和2个M元特征）的简约性分析，该树由38个早三叠世牙形石种组成。根据系统发育时间树，支持一系列的进化谱系：宣汉副鳍鱼-三齿鳍鱼-Platyvillosus regularis;莫氏囊颈鱼-米氏囊颈鱼; Discretella-保守鱼-Paullella meeki;霍默氏三棘鱼-奇奥塞拉;以及三棘鱼-奇奥三棘鱼。支持将Ellisonia agordinato重新归为Hadrodontina agordinae，而将Neospathodus planus归为Triassospathodus属。同时，拟鳍鱼属和鳍鱼属可能属于刚多鱼科而不是细尾鱼科，或细尾鱼科可能是一个复系群而不是一个单系群。分支图表明，Hindeodus、Hadrodontina和Pachycladina为单系，Novispathodus和Triassospathodus分别为并系和复系。此外，P1元件的圆形基腔也是Novispathodus与Triassospathodus的区别之一。新的分类方法为进一步研究早三叠世牙形石的系统分类和演化速率提供了坚实的系统发育基础。
Conodonts are some of the most important biostratigraphic index fossils in the Paleozoic and Triassic because of their rapid evolution and extensive distribution. Here we present a cladistic analysis of Early Triassic conodonts to reexamine the systematic classification and evolutionary relationships of the three related families Anchignathodontidae, Ellisonidae, and Gondolellidae. The tree consists of 38 Early Triassic conodont species with multielement apparatus documented, based on parsimony analysis of 73 discrete morphological characters including 40 P1element characters, 4 P2element characters, 27 S element characters and 2 M element characters. Based on the phylogenetic time tree, a series of evolutionary lineages are supported:Parafurnishius xuanhanensis–Furnishius triserratus–Platyvillosus regularis;Scythogondolella mosheri–Scythogondolella milleri;Discretella–Conservatella–Paullella meeki;Triassospathodus homeri–Chiosella; andTriassospathodus symmetricus–Triassospathodus chioensis. Reassignment ofEllisonia agordinato beHadrodontina agordinais supported whileNeospathodus planusshould be resigned to the genusTriassospathodus. Meanwhile,ParafurnishiusandFurnishiusmay belong to Gondolellidae rather than Ellisonidae or Ellisonidae may be a polyphyletic group rather than a monophyletic group. The cladogram suggests thatHindeodus,HadrodontinaandPachycladinaare monophyletic, whilstNovispathodusandTriassospathodusare paraphyletic and polyphyletic, respectively. In addition, a P1element with a round basal cavity is an important trait to distinguishNovispathodusfromTriassospathodus. The cladogram and revised classification provide a robust phylogenetic foundation for further investigations on systematic classification and evolutionary rates of conodonts during the Early Triassic.