New materials of Cervidae (Artiodactyla, Mammalia) from Tuchengzi of Huade, Nei Mongol, North China
摘要： Five taxa of Cervidae were identified from the new collection at Tuchengzi locality in Huade, Nei Mongol: Eostyloceros blainvillei, E. triangularis, Euprox sp., Cervavitus huadeensis and C. shanxius, among which the first three taxa were discovered for the first time in Huade area, and the dental specimens of the last two taxa from Tuchengzi locality are also described for the first time. E. blainvillei is a large muntiacine, diagnosed by long, thick and medially curved main beam and a relatively long brow tine emerging directly from the burr. It was originally found in Yushe Basin in Shanxi Province, and reported later from Qaidam Basin in Qinghai Province. Huade is the third area yielding the species. E. triangularis distinguishes from E. blainvillei by its special main beam with triangular cross sections, and it was reported only from Yushe Basin. Its presence in Huade extended its geographic distribution northward to Nei Mongol. Euprox is a transitional form of cervids from permanent antlers to seasonally deciduous ones and it is found in several localities across Eurasia. Huade is the third area in Nei Mongol yielding the taxon after Tung Gur and Siziwang Qi (Siziwang Banner). C. huadeensis is a pliocervine with four tines, and particularly with two distal tines sword-like. It is found at Tuchengzi for the second time, but not elsewhere so far, and it seems to be an endemic taxon. C. shanxius distinguishes from C. novorossiae by absence of Palaeomeryx fold on lower molars. It is widely found in Shanxi, Shaanxi, Gansu and Nei Mongol of northern China. It is often found with numerous specimens in a locality that indicates it lived in large herds. E. blainvillei, E. triangularis and C. shanxius are main members of Yushe I, i.e. Mahui Formation or Baodean. Euprox appeared also mainly in the Late Miocene. The geological age of Tuchengzi locality based on excavated cervids is therefore the Late Miocene. The numerous specimens of C. shanxius indicates forested environment in Huade area in that age.
继1959年中苏古生物联合考察队在内蒙古化德地区发掘采集到大量晚中新世哺乳动物化石后，笔者的课题组于2013~2016年间在化德的土城子地点发掘采集到不少哺乳动物化石。经过修理和研究，鉴定出鹿科化石的5个种类：布氏始柱角鹿(Eostyloceros blainvillei), 三角始柱角鹿(E. triangularis), 真角鹿未定种(Euprox sp.), 化德祖鹿(Cervavitus huadeensis)和山西祖鹿(C. shanxius)。其中前3个种类是在化德地区首次发现，而后两个种的牙齿材料也是在土城子地点首次记述。布氏始柱角鹿是一种较大的麂类，以其鹿角具一个粗长而内弯的主枝及一个直接从角环上伸出的较长的眉枝为特征，以前主要发现于山西的榆社盆地，在青海柴达木盆地也找到过，而化德是出现这个种类的第三个地区。三角始柱角鹿以其主枝横切面呈三角形而与布氏始柱角鹿相区别，以前仅见于榆社盆地，因此新发现的三角始柱角鹿将其地理分布范围扩大到内蒙古。真角鹿是从非脱换型鹿角向季节性脱换型鹿角过渡的代表，在欧亚大陆都有分布，化德是继通古尔和四子王旗之后在内蒙古发现这个属的第三个地区。化德祖鹿的鹿角具有4个枝，远端两个枝剑形，在土城子地点是第二次发现，但目前尚未在其他地区发现过，似乎是化德一带的地方种类。山西祖鹿以其下臼齿不具古鹿褶而与新罗斯祖鹿(Cervavitus novorossiae)相区别。山西祖鹿在中国北方的分布较广，主要见于山西、陕西、甘肃和内蒙古，而且在每个地点的化石标本较多，指示其种群密度较大。布氏始柱角鹿、三角始柱角鹿和山西祖鹿是榆社盆地中榆社I带的主要鹿科成员，出现在岩石地层的马会组或生物年代学的保德期。真角鹿的时代分布主要在晚中新世。因此根据土城子地点的鹿科化石判断其地质时代应为晚中新世，而较多的山西祖鹿标本指示化德一带在晚中新世有较广的森林。