华南古新世哺乳类一新科

本文记述了一个新科(丽(犭亚)科)的两个新属和四个新种。文中除对四新种进行了较详细的描述与对比外,还初步讨论了丽(犭亚)科、(犭亚)科与假古猬科同Kennalestes和zalambdalestids之间的亲缘关系。从目前材料来看,在形态上,丽(犭亚)比Gypsonictops更接近于Kennalestes。丽(犭亚)科有可能是后者的古新世后裔,(犭亚)科和假古猬科的起源或许与达种白垩纪真兽类也有密切关系。

NEW ANAGALOID MAMMALS FROM PALEOCENE OF SOUTH CHINA

Some mammalian fossils collected from the middle-lower Paleocene of South China in 1974 are reported in this note. They are described as four new spicies assigned to two genera and tentatively considered to represent a new anagalid family, the Astigalidae.Astigalids, as well as pseudictopids and anagalids, have probably derived from Kennalestes-like mammals. However, astigalids are more similar to the Cretaceous species in dental morphology than the two others. It seems unlikely that zalambdalestids referable to the order Anagalida can be considered as their derict ancestor.All these fossils described in the report, with the exception of the one specimen which was found in the Qianshan Basin, Anhui, were from the Nanxiong Basin, Guangdong.Order Anagalida Family Astigalidae Fam. nov.Type genus Astigale gen. nov.Included genus Astigale gen. nov. and Zhujegale gen. nov.Distribution Middle and Lower Paleocene, South China.Diagnosis Dental formula: I_?~? C_1~1 P_4~4 M_3~3. Muzzle long and narrow, horizontal ramus rather slender. Upper incisors small, canines strong. P_(1-2)~(1-2) each with a trenchant main cusp, P_1~1 single-rooted, P_2~2 doublerooted. P~(3～4) cosisting of tall main cusps and low protocones. Upper molars wide, with distinct conules, developed premetaconule crista, and hooklike parastyles, Apices of paracone and metacone separated, but fused throughout most of height. Pre. and postcingula low, lingually formed hypocone shelf. Paraconids and metaconids of lower molars connated, the latter taller than protoconids. M_(1-2) hypoconulid and entoconid subequal. M_3~3 not reduced.Astigale gen. nov.Type species A. nanxiogensis sp. nov.Included species A. nanxiogensis sp. nov. and A. wanensis sp. nov.Distribution Middle-Lower Paleocene, Guangdong and Anhui.Diagnosis Lower jaw with long diastemas anterior and posterior to P_1~1 and P_2~2. P~(3-4) metacone incipient, P~4 preprotocrista terminated on the interior border of main cusp, and metastyle distinct. Protocone and metacone of upper molars high, paraconule prominent, and premetaconule crista visible. M~(1-2) with developed metastyle, hook-like parastyles inflected anteriorly. P_(3-4) laterally compressed. P_4 with simple talonid crest. Lower jaw with, two mental foramens beneath P_1 and P_3 respectly, angular process slightly recurved interiorly.Astigale nanxiongensis gen. et sp. nov.Type A skull with lower jaw (V5215).Horizon and Locality Shanghu formation, Lofochai group, middle and lower Paleocene; NE 500 m. Jintang, Zhuje Commune, Nanxiong County, Guangdong.Diagnosis P_4 with incipient metacone and a cuspule on the posterior margin. M_3 entoconid developed and hypoconulid high.Astigale wanensis gen. et sp. nov.Type A right lower jaw (V5216).Horizon and Locality Lower Wanghudum formation, lower-middle Paleocene; E 500 m. Haixingdi, Qianshan, Anhui.Diagnosis Lower jaw relatively robust. P_4 metaconid very weak. Lower molars with rather reduced paraconid and feeble ectocingulum. Enctoconid of M_3 small, hypoconulid strong. Recurved angular process similar to that of Asiaryctes in outline.Zhujegale gen. nov.Type species Z. lirenensis sp. nov.Included species Z. lirenensis sp. nov. and Z. jintangensis sp. nov.Distribution Middle-Lower Paleocene, Guangdong.Diagnosis Smaller than Astigale in size. P~2 triangular at the base. Diasteme between P~2 and P~3 short, P~(3-4) main cusps rather not swollen and metacones small or absent. Paracones and metacones of upper molars laterally compressed, preconule crista distinct, paraconule developed, postparaconule crista absent, parastyle not so prominent as astigale, no metastyle. P_4 almost fully molariform with developed paraconid and metaconid, and with two cuspules on postcingulum.Z. lirenensis sp. nov.Type A right maxilla, a left lower jaw and a right P_4 (V6088).Horizon and Locality Shanghu formation, Lofochai group, middle and lower Paleocene; Liren, Zhuji Commune, Nanxiong County, Guangdong.Diagnosis P~4 with incipient metacone, parastyle strong, preprotocrista and postprotocrista low and feeble, pre. and postcingula weak. Upper molars short but wide, parastyle lower, cingula reduced, paraconule large.Z. Jintangensis sp. nov.Type A left maxilla with P~4-M~3 (V6089).Paratype A poor broken maxilla with left P~4-M~3, right P~3-M~3 (V6090) and a right maxilla with P~3-M~3 (V6091).Horizon and Locality Shanghu formation, Lofochai group, middle and lower Paleocene; Jintang, Zhuji Commune, Nanxiong County, Guangdong.Diagnosis Size smaller than Z. lirenensis. P~4 lacking metacone, with developed preprotocrista and postprotocrista. Upper molars wide, pre. and postcingula rather strong, the latter lingually inflanted into hypocone-like, parastyle slightly conical, metastyle absent, cingulum of M~2 continuous.