TNT script.

The Late Jurassic fossil deposits of southern Germany, collectively known as the ’Solnhofen Archipelago’, are one of the world’s most important sources of Mesozoic vertebrates. Complete skeletons of cartilaginous fishes (Chondrichthyes), whose skeletal remains are rare in the fossil record and therefore all the more valuable, are represented, among others, by exceptionally well-preserved rays (superorder Batomorphii). Despite their potential for research in several areas, including taxonomy, morphology, ecology, and phylogeny, the number of studies on these chondrichthyans is still very limited. Here, we identify a previously unknown ray, †Apolithabatis seioma gen. et sp. nov., which represents the first record of a ray species from the upper Kimmeridgian of Painten, Germany, and thus the oldest Late Jurassic ray taxon from Germany based on skeletal remains. This new batomorph is characterised by a unique body shape and a combination of skeletal features that distinguish it readily from all other known Late Jurassic rays. Two different morphometric approaches confirm differences in body shape and proportions to all known Late Jurassic conspecifics. We thus extend the recent taxonomic revision of these rays and include all described holomorphic specimens in a phylogenetic framework using strict cladistic principles. The phylogenetic analysis reveals all Late Jurassic batomorphs to represent a monophyletic group, for which we introduce the new order Apolithabatiformes, which is sister to all other batomorphs representing a stem group. While the phylogenetic relationships within Apolithabatiformes ord. nov. remain largely unresolved, †Apolithabatis gen. nov. is placed as the sister to †Aellopobatis. This highlights that, despite considerable progress in our understanding of the diversity and phylogeny of early rays, difficulties remain in establishing robust relationships within batomorphs. We therefore emphasise the importance of comprehensive studies of completely preserved fossil cartilaginous fishes to obtain a better understanding of chondrichthyan evolution and their systematics in deep time.德国南部的晚侏罗世化石沉积群，通称为‘索伦霍芬群岛（Solnhofen Archipelago）’，是全球最重要的中生代脊椎动物化石产出地之一。软骨鱼类（Chondrichthyes）的完整骨架在化石记录中极为罕见，因此愈发珍贵，其中以保存异常完好的鳐形总目（Batomorphii）化石最为典型。尽管这类软骨鱼类在分类学、形态学、生态学以及系统发育学等多个研究领域均具有极高潜力，但相关研究至今仍极为匮乏。本次研究中，我们描述了一种此前未被记录的鳐类新属新种：†Apolithabatis seioma gen. et sp. nov.，该物种是德国潘滕（Painten）地区上基默里奇阶鳐类的首个化石记录，同时也是德国境内基于骨骼残骸发现的最古老晚侏罗世鳐类分类单元。这一全新的鳐形总目类群具有独特的躯体形态，且其骨骼特征组合明显区别于所有已知晚侏罗世鳐类。两种不同的形态测量分析均证实，该类群的躯体形态与比例均显著区别于所有已知晚侏罗世鳐类。我们拓展了近期针对该类鳐类的分类学修订工作，并基于严格的支序分类学原则，将所有已发表的完整化石标本纳入系统发育分析框架。系统发育分析结果表明，所有晚侏罗世鳐形总目类群均属于一个单系群，我们为该类群建立新目Apolithabatiformes，其作为干群类群，与所有其他鳐形总目类群互为姊妹群。尽管Apolithabatiformes新目内部的系统发育关系仍未完全厘清，但†Apolithabatis新属被置于与†Aellopobatis互为姊妹群的位置。这一结果表明，尽管学界对早期鳐类的多样性与系统发育研究已取得长足进展，但要厘清鳐形总目内部可靠的系统发育关系仍存在诸多困难。因此，我们强调需对完整保存的软骨鱼类化石开展系统性研究，以更深入地理解远古时期软骨鱼类的演化历程及其分类系统。