Reappraisal of New Zealand and Australian Ordovician caryocaridids presents insight into phyllocarid phylogeny

Caryocaridids exhibited a wide geographical distribution and high diversity during the Great Ordovician Biodiversification Event. The global geographical distribution, limited taxonomic examination and lack of insight into preservational conditions have collectively contributed to an inadequate systematic assessment of Ordovician caryocaridids. To address this situation, we re-examined Ordovician caryocaridid specimens from Australia and New Zealand. Considering these findings, we establish <i>Rhinopterocaris fordycei</i> sp. nov. This new species is characterized by the presence of a well-developed anterior carapace horn, a rounded, truncated posteroventral margin, and furcal rami that lack triangular expansion and spines. In doing so, we confirm the validity of <i>Rhinopterocaris</i>. We reclassify specimens of <i>Lingulocaris maccoyi</i> Etheridge, 1892 into <i>Rhinopterocaris maccoyi</i> (Etheridge, 1892) and highlight that specimens previously reported as <i>Rhinopterocaris maccoyi</i> belong in <i>Jellicaris stewarti</i>. A phylogenetic analysis of 44 Paleozoic phyllocarids reveals that <i>Rhinopterocaris</i> is basal within caryocaridids and is a sister group to younger caryocaridids. Finally, we present a hypothetical evolutionary lineage of caryocaridids and explore the evolutionary history of the group. http://zoobank.org/urn:lsid:zoobank.org:pub:8DB2B405-F13A-480D-919E-48E43C048B9A

在奥陶纪生物大辐射事件（Great Ordovician Biodiversification Event）期间，沟肋虾科（Caryocaridids）类群展现出广泛的地理分布与极高的物种多样性。由于该类群的全球分布范围、有限的分类学研究以及对其保存条件认识不足，共同导致奥陶纪沟肋虾科的系统学评估尚不充分。为解决这一问题，本研究重新检视了产自澳大利亚与新西兰的奥陶纪沟肋虾科标本。基于上述研究结果，我们建立新种*福特伊翅鼻虾（Rhinopterocaris fordycei）* sp. nov.。该新种的鉴别特征为：具有发育良好的背甲前角、圆润且截平的后腹缘，以及不具三角形扩展结构与棘刺的尾叉支。借此我们确认了翅鼻虾属（*Rhinopterocaris*）的分类有效性。我们将1892年Etheridge发表的*麦科伊舌虾（Lingulocaris maccoyi）* Etheridge, 1892的标本重新归入*麦科伊翅鼻虾（Rhinopterocaris maccoyi）* (Etheridge, 1892)，并指出此前被报道为*麦科伊翅鼻虾（Rhinopterocaris maccoyi）*的标本实际隶属于*斯图尔特杰尔虾（Jellicaris stewarti）*。对44种古生代叶虾类（phyllocarids）的系统发育分析显示，翅鼻虾属（*Rhinopterocaris*）位于沟肋虾科的基干位置，且与更晚演化的沟肋虾科类群构成姊妹群。最后，我们构建了沟肋虾科的假想演化谱系，并探讨了该类群的演化历史。http://zoobank.org/urn:lsid:zoobank.org:pub:8DB2B405-F13A-480D-919E-48E43C048B9A