内蒙古呼和勃尔和陡坎晚始新世伊尔丁曼哈层及其哺乳动物群

<正> 呼和勃尔和陡坎,位于二连浩特市西南40余公里,在苏尼特右旗额仁诺尔公社所在地——毛登正东20余公里,即美国自然历史博物馆中亚考察团所谓“马捷茨营地”(CampMargetts)之所在地区(见 Radinsky,1964)。过去在此地区发现的早第三纪化石哺乳类,屡有报道,唯所记述之化石均注以“伊尔丁曼哈组(或层)”,莫一例外。1975—1977年,中国科学院古脊椎动物与古人类研究所、内蒙古区测队以及内蒙古

IRDIN MANHA UPPER EOCENE AND ITS MAMMALIAN FAUNA AT HUHEBOLHE CLIFF IN CENTRAL INNER MONGOLIA

Huhebolhe Cliff of Inner Mongolia,i.e.“Camp Margetts”(see Radinsky,1964),is situated 40km.(25 miles)to the southwest of Erenhot Shi city and 20km.to theeast of Maoden(Eren Nor Commune,Sunid Youqi).Formerly,all the fossils found in this area was considered to be of Upper EoceneIrdin Manha Formation.But,recent investigation indicates that the early Tertiarystrata of Camp Margetts area at least can be further subdivided into three distinctparts:1)Upper:Irdin Manha(Late Eocene),with fossil mammals described in thispaper(field loc.no.77037)and others,about 5m thick.2)Middle:Arshanto(Middle Eocene,with 35 mammalian species,including 27new ones,are recognized at present in the fauna(Qi,under investigation).(77027,77034,77036,77039),about 30m.3)Lower:Bayan Ulan(Early Eocene),with Mongolotherium sp.etc.(underinvestigation).about 36m.Mammalian species known in the Irdin Manha of Huhebolhe Cliff are as following:Order CondylarthraFam.Arctocyonidae Murray,1866 Gen.Paratriisodon Chow,1959Paratriisodon gigas Chow,Li et Chang(Chang),1973Material:Ⅴ 5806.1—4.two broken upper molars;a lower molar,and an incisor.Order Pantodonta gen.et sp.indet.Material:Ⅴ 5807,an incisor.Order PerissodactylaFam.Brontotheriidae Marsh,1873Protitan minor Granger et Gregory,1943Protitan sp.Material:Ⅴ 5808.1—5,a broken maxilla with half M~2 and a M~3;a left M~1;a rightfemur;a left tarsal bone;a left intermediate carpal bone.Fam.Lophialetidae Radinsky,1965Lophialetes expeditus Matthew et Granger,1925Material:Ⅴ 5809,a mandible with dP_(2-4) and M_1.Fam.Hyracodontidae Cope,1939Forstercooperia confluens Wood,2nd,1963These fossils,except Protitan minor and Forsterccoperia confluens,were collectedin 1977.Paratriisodon gigas is known for the first time in Inner Mongolia.It was firstreported by Chou(Chow,1959)as Paratriisodon sp.Later,Chou,Li and Chang(1973)named it as a new species,i.e.Paratriisodon gigas.Diagnosis of Paratriisodon gigas:1)size very large;2)paracone and metaconesubequal;3)cingula developed;4)paraconule and metaconule present on uppermolars;5)a distinct transverse groove on lower molar between the main cusp(prd)and metastylid.