河南淅川始新世核桃园组肉齿类和食肉类化石

这里记述了河南淅川核桃园组三种肉齿类: Propterodon sp., ? P. pishigouensis sp. nov.和 Sarkastodon henanensis sp. nov. 讨论了小孑鬣兽 (Prolaena parva Xu et al.) 的分类位置,并记述了卢氏细齿兽 (Miaeis lushiensis Chow) 的新增材料.

FOSSIL CREODONTS AND CARNIVORES (MAMMALIA) FROM THE HETAOYUAN EOCENE OF HENAN

Eocene carnivorous mammals are poorly known in Asia, only twelve species on record in China. Relatively, Pishigou, an Irdinmanhan fossil locality, seems to produce more material of creodonts and carnivores than other Eocene localities. Two species, Proleana parva and Miacis lushiensis, were described by Xu and others (1979), and other creodonts, ?Sinopa sp. and ?Tritemnodon sp., have/been reportel by Gao Yu (1976) from the Hetaoyuan Formation at Pishigou, near Hetaoyuan Village of Xichuan County, Henan. More material of carnivorous mammals was recently recovered from the same locality. In this paper, the new specimens and the available speeimens collected separately in 1959, 1960, and 1973 are described and reexamined. Creodonta Cope, 1875 Hyaenodontidae Leidy, 1865 Proviverrinae Matthew, 1909 Propterodon sp. (Text-fig. 1; P1. I, Fig. 1-2) A fragmentary right mandible with imcomplete P_8-M_3 and P_2 alveoli (IVPP. V7996) originally identified to ?Tritemnodon sp. by Gao Yu (1976), and now is assigned to the genus Propterodon as the paraconid moderately shifted anteriorly and talonid of M_3 reduced. The Hetaoyuan species differs from the genotype, P. morrisi, from the Irdin Manha Formation of Nei Mongol in having the mueh reduced talonid of M_3 and the relatively developed metaconid of the lower molars. A trigonid of right M_1 (IVPP. V7996. 1) is also referred to the genus Propterodon. ?Propterodon pishigouensis sp. nov. (Text-fig. 2; Pl. I, Fig. 3) Type Partial left mandible with P_4-M_1 (IVPP. V7997). Diagnosis Main cusp of P_4 with shaft recurved posteriorly and its height larger than the dental length, talonid of P_4 strong and wide. Talonid of M_1 relatively long and high. Oxyaenidae Cope, 1877 Oxyaeninae Wortman, 1902 Sarkastodon henanensis sp. nov. (Text-fig. 3; Pl. I, Fig. 4) Type A left M_1 (IVPP. V7998). Diagnosis Trigonid of M_1 narrow and long, metaconid small and posteriorly shifted. Talonid reduced but basing, and keeping clear hypoconid and hypoconulid. Remarks The posteriorly shifted metacondi, strong paraconid and protoconid, and reduced talonid suggest the Hetaoyuan species is morphylogically similar to the advanced oxyaenines, Patriofelis and Sarkastodon. A distinct difference of M_1 of Patriofelis from the Hetaoyuan species is the development of hypoconid into a median, anteroposterior ridge. The presence of lingual rim of talonid on M_1 is easily distinguished the new taxon from the Sarkastodon mongoliensis of Nei Mongol. Carnivora Bowdich, 1821 Miacidae Cope, 1880 Miacis lushiensis Chow, 1975 (Text-fig. 4; Pl. I, Fig. 5-6) Xu and others (1979) have referred a complete right mandible from the Hetaoyuan Formation to M. lushiensis, which was decribed by Chow (1975) on the basis of the material collected from the Lushi Formation of the Lushi Basin. In addition, a right M~1 (IVPP. V7999) collected recently from Pishigou, may be referable to M. lushiensis. The M~1 is distinct from the type specimen of M. invitus of the Irdin Manha For mation in having tapered lingual edge, reduced anterior and posterior wings of protocone, prominent conules, and posterolingually developed lingual cingulum. Morphylogically, M. lushiensis is relatively close to M. hargeri from the upper Bridger Eocene of North America, but difference between the two species is clear. M. lushiensis has less reduced M_3, subequal height of P_3 and P_4, and developed postero-lingual cingulum on M~1. The following characters may add to the diagnosis of M. lushiensis: P_1-M_3 = 40.2 41 mm. Diastema Dbetween P_1 and P_2 relatively long, height of P_3 and P_4 subequal, without accessory cusp, P_4 with accessory cusp on the posterior edge of main cusp and developed posterior cingulum. Talonid of M_1 wide, M_2 short and wide, M, less reduced. M~1 with pointed lingual part and developed postero-lingual eingulum. Discussion Prolaena parva was considered as an oxyaenid based on a fragmentary right mandible (V5361) (Xu and others, 1979), but then we place this species in the subfamily Limnocyoninae of the family Hyaenodontidae, after reobserved the specimen. Prolaena has a slightly reduced M_1 and the talonid of M_2 nearly subequal to that of M_1 in size, whereas in the advanced oxyaenines M_1 is much reduced and the talonid of M_2 is less developed. Most of the carnivorous mammals collected from the Hetaoyuan Formation are evidently comparable to the corresponding Eocene genera or species of North America. Although the generic name, Propterodon, was named on/the basis of an European specimen (Martin, 1906), but this specimen has been transformed to another genus Prodissopsalis and Asiatic species, Propterodon morrisi, has been assigned to genotype by Van Valen (1965). A conspicuous difference between Prodissopsalis of Europe and the known Asiatic species of Propterodon is the development of the molar talonid. The Asiatic species possess much reduced talonid on which the lingual rim has partially disappeared, while in Prodissopsalis the talonid is unreduced. It is not unique that Tritemnodon of North America also has reduced talonid rim, and the lingual rim on the talonid of Metasinopa in Africa is absent. The definite relationships of these proviverrines with reduced talonid of lower molars, of course, await further examination, but it is clear that the Asiatic species of Propterodon has no close relationship to the Lutetian proviverrines of Europe.