记大连晚更新世马属一新种

本文记述在大连复县古龙山洞穴堆积中发现的马属 (Epuus) 的—新种 (E. dalianensis sp. nov). 它是晚更新世的一种大型马类,曾广泛地分布于中国北方.

NOTE ON A NEW LATE PLEISTOCENE EQUUS FROM DALIAN

The mammalian fauna was from Gulongshan Cave in Fuxian County, Dalian (39°41′15″ N, 122°0l′59″ E). The Gulongshan fauna is dated to 17,610 years B.P. by C~(14) technique. According to Uranium-series dating, the fossils have reported dates of 20,000-40,000 years B.P. These dates demonstrated that the mammalian fauna may roughly be correlated with the late Late Pleistocene or O~(18) stages 2-4 in deep-sea sediments. There are 3 species of Equus in the Gulongshan fauna: the large wild horse, the small wild horse and the Asiatic wild ass. The latter two species were described many years ago (Boule and Teilhard, 1928), while the former (Equus dalianensis) is a new species of Equus, which was broadly distributed over the northern China in the late Late Pleistocene. Just as Dalquest (1978) thought, "Equus" is a composite genus. Various classifications with division into genera and subgenera, have been proposed. According to Skinner (1972) and Dalquest (1978), in the subgenus Equus (true horses), the ectoflexid (protoconid-hypoconid valley) of the lower malars is deep, penetrating well into the metaconid-metastylid isthmus, and usually is broad with a blunt or flat end. In the subgenus Hemionus (the Asiatic wild asses), the ectoflexid of the molars is shallow, not Penetrating into the isthmus, and USUally slender with a more pointed end The shape of the linguaflexid (metaconid-metastylid valley) of the lower check teeth is an another helpful character. The subgenus Equus (true horses) is characterized by broad and shallow, usually U-shaped linguafiexids, while in the subgenus Hemionus (the Asiatic wild asses), the linguaflexids are narrow and usually V-shaped. It is clear that the ectoflexid in E. dalianensis penetrates deeply into the isthmus. In most of the lower check teeth of E. dalianensis, the linguaflexids are broad and U-shaped. So E. dalianensis belongs to the subgenus Equus (true horses). Though it is close to E. przewalskyi in size of the upper and lower check teeth (Tables 1-2), E. dalianensis is a quite large horse and has a withers-size of 142-152 cm. Its metacarpals are about 231-249.5 mm long (the largest frequency is in the group 238.3-246.3 mm) and 49-61 mm wide at the proximal end (the largest frequency is in the group 54.4-56.4 mm) (according to the measurements for 30 specimens, Table. 3). Its metatarsals are about 265-293 mm long (the largest frequency is in the group 276.5-282.5 mm) and 50-60 mm wide at the proximal end (the largest frequency is in the group 52.9-54.4 mm) (according to the measurements for 32 specimens, Table. 4). Therefore, E. dalianensis is much taller than the living species E. przewaIskyi. Just as Nobis (1971) said, "Recent Przewalski-horses have a witherssize of 134.0 cm on an average and have relatively big teeth". These characters can distinguish E. dalianensis from E. przewalskyi.