中国首次发现恐象化石

FIRST DISCOVERY OF DEINOTHERE IN CHINA

记述了一件恐象类的下颌。经查证,该下颌产于甘肃临夏州东乡县班土村晚中新世柳树组底部的砂岩透镜体中。根据联合部斜向前下方和p3具下内尖等特征,该下颌被归入原恐象属Prodeinotherium。该下颌以p3相对于其他颊齿特别小、无真正下外脊而区别于该属已知各种。这是中国目前所知惟一一件恐象化石,故定名为中华原恐象P.sinense。恐象类在欧洲、南亚和非洲早一中中新世已广泛分布,至晚中新世已十分进步。中华原恐象一方面保留了某些早期恐象的性状,另一方面又具有一些自身特有的性状。这表明中华原恐象可能较早从恐象主干中分出,而后成为独立发展起来的一支。在中国或周边地区早-中中新世地层中应该还有恐象化石,等待我们去发现。

While visiting the Nei Mongol Museum in July 2005, the two senior authors of the present paper happened to have come across a mandible of apparently a kind of deinothere, although it was still largely embedded in yellow sandstone. The deinothere morphology of the specimen has soon been clearly revealed after further preparation. Fully realized the possible importance of the specimen, the authors immediately started to make every effort to find out its real provenance. Through repeated inquiries from the ＂dragon-bone＂ dealer who sold the mandible to the museum, Li Hong finally succeeded in locating the place where the fossil came, a village called Bantu in Dongxiang, Gansu. In order to eliminate any possible doubts, Deng Tao went to Bantu in November, 2006, and found the villager who had taken charge of the excavation at the site where the mandible had been unearthed. Being the single object with large teeth of some value among the large quantity of turtle shells from this site, the deinothere mandible had left a deep impression on the villager, and this could account for the easy finding of the site. A closer comparison of the sediments and the preservation states of the fossils of the site against those ob- served on the deinothere mandible left almost no doubt to Deng that this should be the right site of the deinothere mandible. As observed by Deng, this site is one of a few lenses composed of grayish yellow coarse sandstone, with particularly rich turtle shells, about 100 m high on a south-facing slope （ Fig. 1 ）. These lenses are located in the very basal part of Liushu Formation, which is paleontologically dated as of early Late Miocene in age. Unconformably underlying is a layer of conglomerates, a widespread unit highly characteristic of the top part of the Middle Miocene Hujialiang Formation （Tungurian） in the Linxia Tertiary basin. Some 2.5 km west of Bantu, from about the same level as the above lenses, a rich mammalian fauna was reported （Deng, 2001 ）. It is certainly of early Late Miocene in age （equivalent to the European Vallesian）, consisting of Dinocrocuta , Tetralophodon , Hipparion , Parelasmotherium , Ningxiatherium and Shaanxispira, etc.