The carditid genus Cyclocardia is currently the most diverse genus of the family, including nearly 180 nominal species encompassing wide stratigraphical (Cretaceous–Recent) and geographical (Antarctica, South and North America, Europe, Africa, Alaska, Russia, Japan and New Zealand) ranges. Due to the lack of autapomorphies in the diagnosis of the genus and its large account of species, we re‐evaluate the systematic and phylogenetic status of Cyclocardia. We applied three approaches: bibliographic revision, phylogenetic analysis and an exploration of morphological disparity. We used a shell–character matrix comprising 65 taxa (2 outgroups, 29 non‐Cyclocardia carditids and 28 species of Cyclocardia) for phylogenetic and disparity analyses. Maximum Observable Rescaled Distances was used to construct a distance matrix to compare Cyclocardia species and other carditid groups. According to our results, Cyclocardia represents a non‐monophyletic taxon and is thus a ‘wastebasket taxon’, chiefly because its diagnosis was based mainly on plesiomorphic characters. The European species C. kickxi and C. chameformis are placed within Scalaricardita, and the previously proposed genus Crassicardia is monophyletic (including C. crassidens, C. crebricostata, C. isaotakii and C. rjabininae). Three new genera are proposed for new groups identified by the phylogenetic analysis: South American Oesterheldia gen. nov. (including O. cannada and O. dalek), western North American Coanicardita gen. nov. (including C. ventricosa and C. occidentalis), and North Pacific Hippocampocardia gen. nov. (including H. barbarensis, H. hamiltonensis and H. yakatagensis). The newly defined monophyletic Cyclocardia is restricted to the Atlantic Ocean species C. borealis, C. novangliae and C. compressa.

中文翻译：

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Cyclocardia（Conrad）是废纸tax分类单元吗？探索小科（Archiheterodonta，双壳纲）最广泛的属的系统发育

该carditid属Cyclocardia是目前家族中最多样化的属，其中包括近180名义品种涵盖广泛的地层（白垩纪-最近）和地理（南极洲，南美洲，北美洲，欧洲，非洲，阿拉斯加，俄罗斯，日本和新西兰）范围。由于在诊断该属时缺乏自发亚型及其种类繁多，我们重新评估了心动过速的系统和系统发育状况。我们采用了三种方法：书目修订，系统发育分析和形态差异研究。我们使用了壳字符基质，其包含65类群（2个外群，29个非Cyclocardia carditids和28种的Cyclocardia）进行系统发育分析和差异分析。最大可观察的距离重标用于构建距离矩阵来比较Cyclocardia物种和其他carditid基。根据我们的结果，心旋心音代表一种非单分类群，因此是“废纸tax分类群”，主要是因为其诊断主要基于多形性特征。欧洲物种C. kickxi和C. chameformis置于内Scalaricardita，和先前提出的属Crassicardia是单系（包括C. crassidens，C. crebricostata，C. isaotakii和C. rjabininae）。对于通过系统发育分析确定的新群体，提出了三个新属：南美Oesterheldia gen。十一月 （包括O. cannada和O.的Dalek），北美西部Coanicardita根。十一月 （包括C.ventricosa和C.occidentalis），以及北太平洋海马的基因。十一月 （包括H. barbarensis，H. hamiltonensis和H. yakatagensis）。新定义的单系Cyclocardia仅限于大西洋品种C.北欧，C. novangliae和C. compressa。