【作者】 刘艳；

【导师】 孙克勤； 张兆群；

【作者基本信息】 中国地质大学（北京） ， 古生物学与地层学， 2009， 硕士

【摘要】 本文对采自内蒙古通古尔中中新世晚期通古尔组的爪兽化石进行了详细的描述与研究。本文将这批材料归为三个种,分别为Chalicotherium cf. brevirostris,新种Anisodon gobiensis sp. nov.,及未定种Chalicotheriinae gen. et sp. indet.。对Chalicotherium cf. brevirostris的特征的补充主要为:水平支高度从前向后逐渐增加,下颌角突部向腹侧延伸,有臼齿后空间;下颌联合后缘达P3、P4;犬齿与P2间的齿隙较长;颏孔较大,卵圆形,位于齿隙下部前侧;下颌孔位于冠状突下部齿列位置;有门齿和犬齿;三个门齿向外侧依次增大;下臼齿的下三角座略呈U型,下跟座总体上呈V型,下跟座大于下三角座;下臼齿唇侧齿带发育,舌侧发育弱或不发育;M3后齿带发育,且向唇侧倾斜。新种Anisodon gobiensis sp. nov.的主要特征为:下颌支较粗壮,联合部后缘仅达P2,犬齿与P2间的齿隙很长;两个小颏孔,近圆形,位于犬齿齿槽下部后侧;有犬齿,犬齿齿冠顶端圆钝,齿根粗大而长;下臼齿下后附尖微弱,唇侧齿带发育,舌侧齿带略弱,三角座、跟座均为V型;前臼齿远远小于臼齿,前臼齿齿列短。目前将爪兽亚科分为五个属,即Anisodon,Chalicotherium,Butleria,Kalimantsia和Hesperotherium。探讨了爪兽亚科中Chalicotherium与Anisodon两属的特征,认为它们的形态特征极为接近,是否有必要分为两属仍值得商榷,如果为两个属,应该为姊妹群。根据它们的分布特点认为它们在共同演化的过程中,可能是一种相互竞争的关系,且中国的C. cf. brevirostris很可能是Hesperotherium属的祖先。尝试探讨了爪兽对气候环境特征的指示意义,肯定了前人通过动物群组成、生态形态学、孢粉特征及大洋气候恢复确定的气候环境特征。内蒙古通古尔地区中中新世晚期为一种温带温润向干凉过渡,多乔木、灌木的稀树草原环境,全球中中新世气候变冷事件对其的影响不甚明显,可能主要受控于陆地的区域环境。更多还原

【Abstract】 This paper describes and studies in detail the new materials of chalicotheres found from the late Middle Miocene Tunggur Formation of the Tunggur Tableland, Inner Mongolia, China. They are assigned to three taxa respectively, e.g. Chalicotherium cf. brevirostris, Anisodon gobiensis sp. nov., and Chalicotheriinae gen. et sp. indet. After the study of the new materials and revision of old collections, characters of Chalicotherium cf. brevirostris was complemented as: the corpus increases in height posteriorly, the angulus mandibulae expands ventrally, there exists retromolar space; the symphysis extends to P3 or P4; the diastema between the canine and P2 is long; the mental foramen is big, oval shaped, and located at the lateral side of the anterior diastema; the mandible foramen locates posterior to the dental row below the coronoid; there are incisors and canine; three incisors increase from the mesial to the distal; the talonid is more elongated than the trigonid on the lower molars, and the trigonid is U-shaped but the talonid is V-shaped; the buccal cingulum is developed while the lingual cingulum is weak or undeveloped; the posterior cingulum of M3 is well developed, and slopes labially. The new species, Anisodon gobiensis sp. nov., is characterized by having: strong mandible; the symphysis extends to the level of P2; the diastema between the canine and P2 very long; two small mental foramina nearly round and positioned at the posterior part below the canine alveolus; a blunt apex on the canine crown with a strong and long root; on the lower molar, the metastylid very weak; the buccal cingulum developed but the lingual cingulum weak; both trigonid and talonid V-shaped; the lower premolars much smaller than the lower molars, and short lower premolar row.Till now, five genera can be assigned to Chalicotheriinae, e.g. Anisodon, Chalicotherium, Butleria, Kalimantsia, and Hesperotherium. The characters of Chalicotherium and Anisodon of Chalicotheriinae are also discussed. They are very closely related and possibly be a sister group. However, the possibility of congeneric is still waiting for further evidence. By their geological and geographical distribution, they were possibly competitors living in a similar ecological niche, and Chalicotherium cf. brevirostris from China maybe the ancestor of Hesperotherium.The indication of the chalicotheres to climate and environmental changes is also discussed. This paper affirms the former climate and environmental reconstruction by the analysis of faunal composition, ecomorphology and sporopollen data. During the late Middle Miocene, the habitat in the Tunggur region of Inner Mongolia is suggested to be temperate plain zone with more arbors and shrubs. This period, the climate is warm and wet, and getting dry and cool. It’s not obvious that the Globe Cooling Event after Middle Miocene climate optimum affect this region which may be controlled by the terrestrial regional environment.更多还原