记云南路南晚始新世化石獏类

本文记述了在云南省路南县路美邑地区发现的五种始新世化石獏类。这是西南地区该类动物最集中的一次发现。另外,本文对当时獏类在我国的分布以及它们与华北地区、西南地区化石獏类的关系作了初步的探讨。

NOTES ON LATE EOCENE TAPIROIDS FROM THE LUNAN BASIN, EASTERN YUNNAN

This paper describes a small collection of tapiroids collected by an IVPP field team in Lunan County, Yunnan Province in 1970. The geology of this area has already been reported by Zheng and al. (1978). Tapiroid fossils found at the Lumeiyi site in the Lunan Basin are more abundant and diverse than those previously collected. They comprise five species, four of which are new ones, and are represented by dozens of individuals. The diagnostic characters of the new species are as follows: 1) Lophialetes yunnanensis sp. nov.—A species similar in size and tooth structure to L. expeditus; molar Size increases from M~1 to M~3; the parastyle of a tooth overlaps externally the entire metacone of the tooth anterior to it; molar metalophs rather oblique and connected to both the ectolophs and the labial ends of the paralophs; M~(1-2) metacones flat and long; M~3 metaeone convex labially. 2) Breviodon lumeiyiensis sp. rov.-Essentially identical to B. minutus (Matthew and Granger, 1925) in the structure of the lower jaw and lower teeth but with a relatively longer and narrower symphysis; teeth about 20% narrower than those of B. minutus; M~3 longer than M~2; upper molars (especially M~3) have longer metacones and weaker (but still distinct) posterior processes (ribs) than B. minutus. 3) Hyrachyus lunanensis sp. nov.-P~4 and M~(1-3) relatively narrow; p~4 nonmolariform; M~(1-3) possess anterior and posterior cingula but lack internal and external cingula except M~1 which has a faint external cingulum; M~(1-2) ectolophs flat; M~3 paraloph and metaloph parallel and connected to the ectoloph to form a "U"; M~3 metacone short but distinct. 4) Hyrachyus minor sp. nov. -Somewhat similar to H. lumeiyiensis but much smaller in size; M~3 parastyle very close to paracone. The morphology of the Lumciyi tapiroids resembles that of the Irdin Manha tapiroids on the whole, but the former are more conservative. This conservatism is best revealed by the relatively small size of LophiaIetes cf. expeditus, Brevivdon lumeiyiensis and the two new species of Hyrachyus and by their nonmolariform P~4s. We therefore consider the age of the fossil bearing beds in Yunnan that produced these tapiroids to be earliest Late Eocene.