大连骆驼山地点真枝角鹿的新材料及其意义

2013年以来在辽宁大连骆驼山金远洞堆积(39°23'59.01"N,121°41'20.28"E)进行的系统发掘出土了大量的哺乳动物化石。最近从偶蹄类化石中鉴定出泥河湾期动物群的典型成员布氏真枝角鹿(Eucladoceros boulei)的头骨等材料。金远洞标本角柄粗短,角柄在额骨上向上、外侧方向生长,角枝长而弯曲;头骨额部宽而平,上颌骨高;颊齿齿冠高度中等偏低,上前臼齿舌侧主尖具釉质褶,P2和P3具明显的内中凹,上臼齿具内附尖(底柱),p4没有臼齿化迹象,下臼齿无古鹿褶,但具下外附尖(底柱)。布氏真枝角鹿的产出层位集中在下更新统,因此是早更新世动物群的代表。布氏真枝角鹿以前主要见于华北,向南可达安徽。大连金远洞标本的发现说明这个种的地理分布范围可以到达东北,但从整体看仍是北方动物群的成员。布氏真枝角鹿与欧洲维拉方期的真枝角鹿在形态上有一定的相似性,说明在早更新世期间欧亚大陆的东西两侧存在过动物群的交流。布氏真枝角鹿高度偏低的齿冠指示其食嫩叶的食性,说明在早更新世期间大连金远洞一带很可能存在一定范围的阔叶林环境。

NEW MATERIALS OF EUCLADOCEROS(ARTIODACTYLX,MAMMALIA)FROM LUOTUOSHAN LOCALITY OF DALIAN,LIAONING PROVINCE

A large quantity of mammalian fossils were unearthed during the systematic excavations since 2013 from the Early Pleistocene deposits in Jinyuandong(=Jinyuan Cave)(39°23'59.01"N,121°41'20.28"E)at Luotuoshan in Dalian Municipality,Liaoning Province.A Nihewanian cervid,Eucladoceros boulei,named by Teilhard de Chardin and Piveteau in 1930,was identified from collected materials in recent study.Its pedicles are stout,stretching upwards and laterally,its tines are long and curved;the frontals are wide and flat,the maxillae are high(deep);cheek teeth are mostly brachyodont,the enamel folds on the lingual main cusps of upper premolars are present,entoflexus is evident on P2 and P3,entostyle(basal pillar)is present on upper molars,no molarization tendency on p4,ectostylid(basal pillar)is present but Palaeomeryx fold is absent on lower molars.Eucladoceros is a genus frequently found in European Villafranchian deposits.Only two species of the genus have been confirmed to be present in Chinese Late Neogene and Early Pleistocene deposits.The earliest Eucladoceros in China is E.proboulei from Yushe Basin in the Late Miocene and Pliocene deposits.It is probably the direct ancestor of E.boulei,another species of the genus mainly found in the Early Pleistocene of China.E.boulei was previously found in North China,with southward extension to Anhui Province.The discovery of the species in Jinyuandong indicates that its geographical range extended to Northeast China.The stratigraphic distribution of the species is mainly in the Lower Pleistocene,indicating that it is a representative taxon of the Early Pleistocene faunas.An uncertain species of the genus,Eucladoceros sp.was reported from the Early Pleistocene deposits at Dianzhong in Yunnan Province and it indicates the genus extended to Southern China.The affinity of E.boulei with European Villafranchian E.senezensis implies that there existed faunal exchanges between West Europe and East Asia during the Early Pleistocene.The brachyodont teeth of E.boulei indicates its folivorous and browsing diets,it indicates further the existence of a certain range of broadleaf forest environment in Dalian in the Early Pleistocene.