江西萍乡杨家湾2号洞晚更新世野猪化石研究

New fossils of Late Pleistocene Sus scrofa from Yangjiawan Cave 2,Jiangxi,China

江西萍乡杨家湾2号洞是发育在二叠系灰岩中的溶洞,其中充填了晚更新世的黏土和沙砾堆积;自2015年至今已经挖掘6次,出土了万余件哺乳动物化石标本,其中野猪牙齿化石约占49%,代表目前我国更新世野猪牙齿化石最为丰富的地点。将杨家湾2号洞出土的猪科动物牙齿化石(尤其是犬齿和第三臼齿)与我国南方特有的化石种裴氏猪(Sus peii)和小猪(Sus xiaozhu)及盐井沟出土的野猪化石进行了牙齿形态学比较研究和一系列数据分析(包括散点图、回归分析、变异系数分析和线性判别分析等);所有雄性下犬齿均属于野猪型,数据分析结果也表明,杨家湾2号洞出土的猪科化石可全部归入野猪种(Sus scrofa);尽管雄性下犬齿和上第二及下第三臼齿测量数据的变异范围很大,但都在野猪的变异范围之内。在此基础上,还利用杨家湾2号洞出土的野猪第三臼齿化石进行了种内变异研究,上、下第三臼齿的散点图各自聚为两大聚集区,这一结果很可能是由性别差异所导致而非不同属种混合。中国南方地区早更新世之后的猪科动物基本只有野猪一种,这与毗邻的东南亚地区不同;东南亚的猪科动物十分多样,并且绝大多数具有爪哇疣猪型犬齿。

The YJW(Yangjiawan)Cave 2 of Pingxiang in Jiangxi Province is a karst cave that developed in the Permian limestone of the Changxing Formation,which is filled with clay and grit of Late Pleistocene age.Six excavations have been conducted at the site since 2015.More than ten thousand mammalian fossils have been unearthed,and the wild boar fossils account for approximately 49%,which represents the richest wild boar fossil tooth collection of Pleistocene age in southern China.This study focuses on the studies of the canine teeth and the third molars,and mainly compares fossils of Sus peii and S.xiaozhu in South China and the data of extant S.scrofa respectively in dental morphology and odontometric data analyses which includes scatter plot analysis,regression analysis,coefficient of variation analysis and linear discriminant analysis.The typical scrofic type of the male’s lower canine teeth confirmed the identification of the suid fossils from YJW Cave 2 as S.scrofa.Although the male’s lower canines,the M2s and m3s,are among the most variable teeth in sizes,they stay in the ranges of S.scrofa;furthermore,the scatterplots of both the upper and lower third molars form two distinct clusters respectively,which can probably be attributed to sexual dimorphism rather than resulting from a mixture of different suid species.The post-Early Pleistocene suid fauna in southern China is almost only composed of S.scrofa,which is quite different from the adjacent Southeast Asia where the suid fauna is quite taxonomically diversified and dominated by the verrucosic type.