摘要
浙江金华双龙洞脊椎动物群包括9目24科48种,其中哺乳类47种,爬行类1种.成员中除含有 Ailuropoda melanoleuca baconi, Crocuta ultima, Stegodon orientalis, Megatapirus augustus 和 Sus sp. (cf. xiaozhu)等大熊猫—剑齿象动物群中的典型绝灭种之外,大部分都是现生种类.经 ^(14)C 绝对年代测定,动物群的年代为 7815±385aB.P,晚于江苏溧水神仙洞动物群,早于浙江余姚河姆渡、河南淅川下王岗和广西桂林甑皮岩等遗址动物群,而与云南保山蒲缥遗址动物群接近.研究表明,大熊猫—剑齿象动物群的绝灭年代大约在5000-4000aB. P., 距今5000年的一次降温事件以及后来的人类活动可能是导致这个动物群最后灭绝的直接原因.
The well-known native Ailuropoda-Stegod on Faunas had ever flourished in Pleistocene in South China, and is generally considered died at the end of late Pleistocene. In 1987, the first Holocene Ailuropoda-Stegodon Fauna was discovered at Shuanglong Cave, a famous scenery spot situated in the north of Jinhua, Zhejiang. The faunal assemblage suggests that it be the largest and most integrated of the common Ailuropoda-Stigodon Faunas ever found in the South China Holocene. This discovery is significant not only to the determination of Holocene paleogeography and paleoclimate in South China, but also to the study of its distribution, evolution and extinction. 1. Cave Deposits and Fossiliferous Horizons Shuanglong Cave is located 13 km north of Jinhua, near Dongqian Village with the geographical coordinate of 29°12'N, 119°37'E. It is a horizontal karst cave developed in the thick-be-dded limestone of the Upper Carboniferous Chuanshan Formation, and can be divided into three parts: Outer Hall, Central Hall and lnner Cavern. There are two kinds of deposits in it, one is the solidified tufa and brecciola, the ither loose sediments consisted of clay, sand and micropepble. There collected a great many of vertebrate fossils from reddish yellow loose clay and sand in Inner Cavern, although some are yielded in CentralHall. The fossiliferous deposits in Inner Cavern consist of six layers, and major remains come from the second one. The fossils are all poorly preserved in a state of weak or temperate fossilization. In the light of the assemblages yielded in different horizons, no divergence appear, thus the Shuanglong Cave Fauna is named for them for their conformity as a whole. 2. Characters and age of Shuanglong Cave Fauna Vertebrate fossils collected from Shuanglong Cave contain 48 species, including 47 mammals and 1 reptile, of which 44 species or genera are identical. Its faunal features reflect that it is a common Ailuropoda-Stegodon Fauna ever found in the middle and upper Quaterary of South China. Its noticeable characteristic is that in addition to some typical extinct members of the classic Ailuropoda-Stegodon Fauna such as Ailuropoda melanoleuca baconi, Croeuta ultima, Stegodon orientalis, Megatapirus augustus, and Sus sp. (cf. xiaozhu), most are living forms in which a horde of small mammals are included. The faunal characters are as follows: 1). Shuanglong Cave Fauna has many comparable species with late Pleistocene Ailuropoda-Stegodon Faunas ever found in South China, especially with jiulengshan Fauna at Duan, Guangxi and Xianren Cave Fauna at Xichou, Yunnan, but its lower percentage of extinct forms (10.4%) in dicates a modern nature. 2). Shuanglong Cave Fauna contains some nodern members which were ever as fossil collected only from Holocene deposits or neolithic site and are still alive or stamped out in China at present, such as Macaca cf. mulatta, Didermoerus sp., Rhinoceros cf. sondaicus and Cervus nippon. Macaca mulatta, a primate now living mainly in temperate climate in South China, has only been found in northern and sonthern neolithic sites. Similarly, Cervus nippon, centralizing in the east part of China nowadays, was kept in fossil also in neolithic sites. There are two kinds of rhinoceroses: Rhinoceros cf. sondaicus and Didermocerus sp., of which a part of specimens assigned to the latter may possibly be D. sumatrensis. Although these rhinocerotids have disappeared in China today, their remains were preserved in 7000 aB.P. in neolithic sites such as Hemudu at Yuyao, Zhejiang, Xiawanggang at Xichuan, Henan and Pupiao at Baoshan, Yunnan. 3). The extinct species of Shuanglong Cave Fauna were generally considered becoming extinct before Holocene. Recent discoveries indicate, however, that their living span could be extended to Holocene. Ailuropoda melanoleuca baconi, a subspecies of the contemporary A melanoleuca, had appeared as a fossil in early fissure deposits at Pupiao of Baoshan County, Yunnan; The latest record of Crocuta ultima was reported from the initial Holocene in Shenxian Cave at Lishui, Jiangsu; Stegodon can survived to 4100 aB.P. in southern border area of Yunnan, and Megatapirus augustus was still alive before 5000 aB.P. at Wushan, Sichuan on the north bank of the Yangzte River. Sus xiaozhu has been recorded in early and middle Pleistocene in South China. The structural features of the molars pertaining to Sus sp. (cf. xiaozhu) may suggest a progressive character, but its systematic relationship with a form of pygmy suid now living in Guangxi, China and Singapore has not been determined yet due to poor samples. 4) Of 48 members of Shuanglong Cave Fauna, 43 species are modern forms, amounting to 89.6% of the total. Except for 12 species that ate locally disappeared or stamped out in China, such as Crocidura russula, Anourosorex squamipes, Murina sp., Macaca cf. nemestrina, Rhinopithecus sp., Presbytis sp., Apodemus sytvaticus, Cuon javanicus, Didermocerus sp., Rhinoceros cf. sondaicus, Muntiacus cf. munijak, and Cervus unicolor, 27 forms belong to Zhejiang modern fauna. It is shown upon this that Shuanglong Cave Fauna has an intense modern tint. Compared with Holocene or neolithic site faunas, Shuanglong Cave Fauna share Crocuta ultima and Ailuropoda melanoleuca baconi with Shenxian Cave Fauna and Pupiao Fauna respectively, and its living forms have a good comparison with the neolithic site faunas of Hemudu, Xiawanggang and Zengpiyan at Guilin, Guangxi, but it reflects a primitiveness by its more extinct species. Based on ^(14)C dating of the fossils from the second horizon (7815±385 aB.P.) and combjned with the faunal characters mentioned above, Shuanglong Cave Fauna is reasonably dated early Holocene in age, younger than that of Shenxian Cave Fauna, older than those of Hemudu, Xiawanggang and Zengpiyan neolithic site faunas, but corresponding to that of Pupiao Fauna. 3. Preliminary study on the Age and Cause of Ailuropoda-Stegodon Fauna Extinction The native Ailuropoda-Stegodon Fauna was initiated in early Pleistocene and became prosperous throughout middle and late Pleistocene in South China, and then declined gradually to the end of Pleistocene. The discovery of ShuanglongCave Fauna fully proves that this peculiar fauna could survived into Holocene in South China. As far as known, the latest surviving records of the typical extinct forms of this fauna are documented as follows: that of Ailuropoda melanoleuca baconi, Crocuta ultima and Sus sp. (cf. Xiaozhu) is 7815±385 a.B.P., namely the age of Shuanglong Cave Fauna; that of Megatapirus augustus may be about the age older than 5000 aB.P. in Wushan, Sichuan; and that of Stegodon may possibly be 4100 aB.P. in Southern Yunnan (at Xiaohe Cave in Malipo County). Climatio changes and human activities in Holocene are regarded as the main causes of extinction of these mammals which had once flourished for thousands of years in South China in addition to evolutionary factors themselves. It is testified recently that there once occurred a climatic decline event all over the world around 5000 aB.P. at the end of the warmest Atlantic phase (8000-5000 aB.P.). All fossil sites from which the above extinct forms has been yielded are no later than 5000 a.B.P, except for Xiaohe Cave site lying at the southern border area of Yunnan. This phenomenon is far from accidental and probably related to the climatic decline event. When the sudden cold wave approached, the warm-like animals would be forced to migrate towards the South, in which some in a rare state might became wane due to their poor adaptation to the sudden climatic changes, and others like Stegodon might migrate into southern mountains and valleys where microclimate were available. These kinds of animals could not shun their misfortune of extinction at last as a resuit of both self factors of biological evolution and buman hunting. It can be reasonably inferred that these classic members of Ailuropoda-Stegodon Fauna became extinct around 5000-4000 aB. P. we owe much a debt to Profs. Huang Wanpo, Zheng Shaohua, Gu Yumin, Qiu Zhuding, Ji Hongxiang and Tong Yongsheng of IVPP, Academia Sinica for their instruction and help in our fossil identification and paper composition. Our thanks especially go to Profs. Zheng Shaohua and Huang Wanpo for going over this manuscript and giving valuable advices. And we are grateful to Mrs. Yu Jizhen of the Institute of Zoology, Academia Sinica for her presentation or specimens of living mammals for us to compare with.
出处
《古脊椎动物学报》
CSCD
北大核心
1992年第4期295-312,共18页
Vertebrata Palasiatica
关键词
大熊猫
剑齿象
动物群
浙江
全新世
Shuanglong Cave at Jinhua, Zhejiang
Holocene
Ailuropoda-Stegodon Fauna
