Ishikawa Asato, Zheng Wenjie, Imai Takuya, Hattori Soki, Shibata Masateru, Kawabe Soichiro, Jin Xingsheng
Department of Bioscience and Biotechnology, Fukui Prefectural University, Eiheiji, Fukui, Japan.
Zhejiang Museum of Natural History, Hangzhou, Zhejiang, China.
PeerJ. 2025 Jul 8;13:e19547. doi: 10.7717/peerj.19547. eCollection 2025.
The taxonomic validity of some genera and species within Psittacosauridae has been disputed, including that of , which has been synonymized with previously. To assess the validity of the former genus and species and elucidate the taxonomy and diversity in Psittacosauridae, we describe a nearly complete psittacosaurid skull (ZMNH M12414) with the aid of computed-tomography techniques. The specimen comes from the Lujiatun Unit of the Lower Cretaceous Yixian Formation, Liaoning, northeastern China, which has also produced , , and . ZMNH M12414 exhibits a series of unique features that are also present in the adult referred skull of (IVPP V12617), indicating that both specimens are attributable to the same species within Psittacosauridae. The proportionally large length of the snout used to diagnose . cannot be used for taxonomic distinction of because this character is also found in , supporting that the genus is a junior synonym of . On the other hand, ZMNH M12414 and IVPP V12617 exhibit a set of features that are not observed in any other species of , including . . Because of these features, the specimen in question better fits as its own species within : . A phylogenetic analysis supports the validity of . , where the specimens form an independent species within . The computed-tomography techniques employed in the present study facilitated re-assessment of the taxonomy and morphological diversity of , and its application is encouraged for previously described dinosaur taxa whose validities are in question. By utilizing such techniques, the detailed evaluation of ontogenetic, intraspecific, and interspecific variations will be crucial to understand the true taxonomy and diversity of in future studies.
鹦鹉嘴龙科内一些属和种的分类有效性一直存在争议，包括 ，它之前已被同义于 。为了评估前者属和种的有效性，并阐明鹦鹉嘴龙科的分类和多样性，我们借助计算机断层扫描技术描述了一个近乎完整的鹦鹉嘴龙科头骨（ZMNH M12414）。该标本来自中国东北辽宁省下白垩统义县组的陆家屯单元，该单元还产出了 、 和 。ZMNH M12414展现出一系列独特特征，这些特征在成年的归入 的头骨（IVPP V12617）中也存在，这表明这两个标本都可归属于鹦鹉嘴龙科内的同一物种。用于诊断 的口鼻部相对较大的长度，不能用于 的分类区分，因为这个特征在 中也能找到，这支持了 属是 的次异名。另一方面，ZMNH M12414和IVPP V12617展现出一组在 （包括 ）的任何其他物种中都未观察到的特征。由于这些特征，所讨论的标本更适合作为 中的一个独立物种： 。系统发育分析支持了 的有效性，其中这些标本在 内形成一个独立物种。本研究中使用的计算机断层扫描技术有助于重新评估 的分类和形态多样性，对于有效性存疑的先前描述的恐龙分类群，鼓励应用该技术。通过利用此类技术，对个体发育、种内和种间变异的详细评估对于在未来研究中理解 的真正分类和多样性至关重要。
