Amadori Manuel, Japundžić Sanja, Amalfitano Jacopo, Giusberti Luca, Fornaciari Eliana, Jambura Patrick L, Kriwet Jürgen
Department of Palaeontology, Geozentrum, University of Vienna, Josef-Holaubek-Platz 2, 1090 Vienna, Austria.
Croatian Natural History Museum, Demetrova Ul. 1, 10000 Zagreb, Croatia.
Swiss J Palaeontol. 2025;144(1):2. doi: 10.1186/s13358-024-00340-7. Epub 2025 Jan 8.
A new lower tooth plate of from the Turonian (Upper Cretaceous) of the Dalmatian region (southern Croatia) is documented here for the first time. The specimen represents the first articulated dentition of a ptychodontid shark that has been discovered from the Balkan Peninsula and the most complete ever found for the un-cuspidate species up to now. The reconstruction of the entire lower dentition of based on this exceptionally well-preserved dentition shows a wider crushing plate than previously hypothesised with bulgy teeth limited to the central area. Even though a defined cusp is missing, the occlusal surface of the teeth is undeniably raised and bulgy in some un-cuspidate species of (e.g., ). This compels us to reconsider the use of terms such as high- and low-crowned as well as cuspidate and un-cuspidate. In addition, specimens previously assigned to dubious species (, and ) or even varieties ( var. and var. ) are reassigned here to based on a careful comparison of the type materials. The reassessment of tooth root morphologies provides indicative traits for the identification of different genera of ptychodontid sharks ( and ). The taxonomic revision presented here is crucial for securing a stable taxonomy and systematics of the shell-crushing shark , as well as of all ptychodontid sharks. The resulting updated taxonomy, together with the description and reconstruction of the new crushing plate, greatly contribute to a better understanding of one of the most enigmatic families (Ptychodontidae) of Mesozoic elasmobranchs. The detailed investigation of the new dentition of from Dalmatia is also a further step towards the discovery of Upper Cretaceous ichthyofaunas of one of the most palaeontologically important areas of the Balkan Peninsula.
The online version contains supplementary material available at 10.1186/s13358-024-00340-7.
首次记录了来自达尔马提亚地区（克罗地亚南部）土伦阶（上白垩统）的一块新的下齿板。该标本代表了从巴尔干半岛发现的第一具关节相连的褶齿鲨齿列，也是迄今为止发现的无尖齿物种最完整的齿列。基于这一保存异常完好的齿列对整个下齿列进行的重建显示，其压碎板比之前推测的更宽，且突出的牙齿仅限于中央区域。尽管缺少明确的齿尖，但在某些无尖齿的褶齿鲨物种（如 ）中，牙齿的咬合面无疑是凸起的。这迫使我们重新考虑诸如高冠和低冠以及有尖齿和无尖齿等术语的使用。此外，根据对模式标本的仔细比较，这里将之前归为可疑物种（ 、 和 ）甚至变种（ 变种和 变种）的标本重新归为 。牙根形态的重新评估为识别褶齿鲨不同属（ 和 ）提供了指示性特征。这里提出的分类修订对于确保壳压碎鲨 以及所有褶齿鲨的稳定分类和系统学至关重要。由此产生的更新分类法，连同新压碎板的描述和重建，极大地有助于更好地理解中生代板鳃亚纲最神秘的科之一（褶齿鲨科）。对来自达尔马提亚的新齿列的详细研究也是朝着发现巴尔干半岛古生物学最重要地区之一的上白垩统鱼类群迈出的又一步。
在线版本包含可在10.1186/s13358 - 024 - 00340 - 7获取的补充材料。
