Although the Langshan Formation has been widely regarded as spanning the Aptian to the lower Cenomanian (upper Lower to lower Upper Cretaceous), previous records of rudist bivalves from this formation were limited to the Auroradiolites biconvexus-Magallanesia rutogensis assemblage, which is restricted to upper Aptian to Albian (upper Lower Cretaceous). The discovery of Agriopleura libanica (Astre), along with Offneria murgensis, in the Langshan Formation of the northern Lhasa Terrane represents the first documented occurrence of early Aptian rudist bivalves in China, significantly extending the known stratigraphic range of rudists within this unit. The comparison between A. libanica and Auroradiolites supports the hypothesis that Auroradiolites descended directly from A. libanica, as evidenced by shared ligamentary and myophoral structures, despite differences in left valve convexity and interband morphology. The A. libanica-O. murgensis assemblage confirms the presence of a carbonate seaway in the Nyima region during the early Aptian (late Early Cretaceous), highlighting the significance of the Langshan Formation for reconstructing the paleogeography of northern Lhasa Terrane and the evolution of the Bangong-Nujiang Ocean. The occurrence of A. libanica in the Lhasa Terrane fills a critical geographic gap, bridging its known distribution from Arabia to East Asia during the early Aptian. It represents the first record of this species on the northern margin of the Tethys, as well as the first documentation of early Aptian rudists along the northern margin of the eastern Tethyan Ocean. These discoveries challenge the traditional division between northern and southern Tethyan rudist provinces, demonstrating cross-Tethyan faunal connectivity during the early Aptian. Crown Copyright (c) 2025 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights are reserved, including those for text and data mining, AI training, and similar technologies.