The Early Holocene vertebrate fauna from Aili Cave in Nanling, Anhui

Vertebrate faunas are rare in southern Anhui Province since the Late Pleistocene, which limits the overall understanding of the biostratigraphy in the lower reaches of the Yangtze River. In 2020 and 2024, more than 600 Early Holocene vertebrate subfossils were recovered from Aili Cave, which is located in the transition zone between the southern Anhui Mountainous Area and the lower Yangtze River floodplain. Aili Cave is narrow and inclined in profile; the fossil layer is mainly composed of brown clay, with small amounts of limestone breccia. The fossil assemblage is located at the entrance of the limestone cave system, which is a natural accumulation formed by water transport.The Aili fauna consists of 27 species, including the following taxa: Viperidae gen. et sp. indet., Colubridae gen. et sp. indet., Testudinidae gen. et sp. indet., Phasianidae gen. et sp. indet., Talpinae gen. et sp. indet., Crocidura sp. A, Crocidura sp. B, Rhinolophus ferrumequinum, Typhlomys cinereus, Apodemus draco, Leopoldamys edwardsi, Hystrix brachyura, Macaca sp., Panthera pardus, Paguma larvata, Nyctereutes procyonoides, Canis lupus familiaris, Ursus thibetanus, Meles leucurus, Rhinocerotidae gen. et sp. indet., Sus scrofa, Muntiacus reevesi, Muntiacus gigas, Cervus nippon, Rusa unicolor, Bovinae gen. et sp. indet., and Capricornis sumatraensis. The Aili fauna is mainly composed of recent species from the southern Anhui Mountainous Area, but also includes some regionally extirpated species such as giant tortoises, rhinoceros, giant muntjac and sambar deer.Regional faunal comparisons show that the main components of the recent fauna of the lower reaches of the Yangtze River have been formed since the Early Holocene, characterized by the absence of Pleistocene extinct taxa, such as Crocuta ultima, Megatapirus, Stegodon, and Palearctic endemic taxa, such as Ursus arctos, Equus. Since the Middle Holocene, some taxa have retreated southwards, resulting in regional extirpation. The formation of the recent fauna was the results of both climate change and human activities.