Towards a Supertree of Arthropoda: A Species-Level Supertree of the Spiny, Slipper and Coral Lobsters (Decapoda: Achelata)

While supertrees have been built for many vertebrate groups (notably birds, mammals and dinosaurs), invertebrates have attracted relatively little attention. The paucity of supertrees of arthropods is particularly surprising given their economic and ecological importance, as well as their overwhelming contribution to biodiversity. The absence of comprehensive archives of machine-readable source trees, coupled with the need for software implementing repeatable protocols for managing them, has undoubtedly impeded progress. Here we present a supertree of Achelata (spiny, slipper and coral lobsters) as a proof of concept, constructed using new supertree specific software (the Supertree Toolkit; STK) and following a published protocol. We also introduce a new resource for archiving and managing published source trees. Our supertree of Achelata is synthesised from morphological and molecular source trees, and represents the most complete species-level tree of the group to date. Our findings are consistent with recent taxonomic treatments, confirming the validity of just two families: Palinuridae and Scyllaridae; Synaxidae were resolved within Palinuridae. Monophyletic Silentes and Stridentes lineages are recovered within Palinuridae, and all sub-families within Scyllaridae are found to be monophyletic with the exception of Ibacinae. We demonstrate the feasibility of building larger supertrees of arthropods, with the ultimate objective of building a complete species-level phylogeny for the entire phylum using a divide and conquer strategy.

尽管诸多脊椎动物类群已构建了超树（supertree），尤以鸟类、哺乳类及恐龙类为代表，但无脊椎动物相关研究却相对鲜少受到关注。鉴于节肢动物（arthropods）在经济与生态领域的重要价值，以及其对全球生物多样性的压倒性贡献，节肢动物超树的研究匮乏现状尤其令人意外。目前缺乏完整的机器可读源树（source trees）归档体系，加之亟需开发可实现可重复管理流程的专用软件，这无疑阻碍了相关研究的推进。本研究以螯虾下目（Achelata，包含棘龙虾、蝉虾与珊瑚龙虾）的超树作为概念验证案例，通过全新的超树专用软件——超树工具包（Supertree Toolkit，STK），并遵循已发表的研究流程构建完成。本研究同时推出了一款全新的源树归档与管理工具资源。本次构建的螯虾下目超树整合了形态学与分子生物学源树，是目前该类群最为完整的物种级系统发育树。本研究结果与近期分类学研究结论一致，仅确认了两个有效科：龙虾科（Palinuridae）与蝉虾科（Scyllaridae）；合虾科（Synaxidae）被归入龙虾科范畴。龙虾科内的Silentes与Stridentes演化支均为单系的（monophyletic）；蝉虾科下的所有亚科均为单系的，仅伊巴虾亚科（Ibacinae）除外。本研究证实了构建更大规模节肢动物超树的可行性，最终目标是通过分而治之（divide and conquer）策略，构建整个节肢动物门的完整物种级系统发育树。