甘肃临夏盆地中中新世皇冠鹿—新种(英文)

A new species of crown-antlered deer Stephanocemas (Cervidae,Artiodactyla) from the Middle Miocene of the Linxia Basin in Gansu,China

根据在甘肃临夏盆地中中新世早期东乡组地层中发现的1支成年鹿角、3枚颊齿、1枚距骨和1枚跟骨建立了皇冠鹿新种——广河皇冠鹿(Stephanocemas guangheensis sp.nov.)。它是皇冠鹿属中一个体型相当小的种,其鹿角显著掌状化,在成年个体中具有6个角枝。新种鹿角的组合特征区别于皇冠鹿的其他已知种,如中等大小的掌状部和向上伸展的侧枝;掌状部腹面具短的角柄,其横截面为外缘平直的半圆形;未封闭的脱落疤痕浅凹并布满海绵状孔隙。S.guangheensis比早中新世晚期的S.aralensis和S.actauensis进步,但比中中新世的S.palmatus原始。东乡组是临夏盆地中含化石相当稀少的地层,S.guangheensis的发现为确定该组的地层时代提供了新的依据。

A new species of the crown-antlered deer, Stephanocemas guangheensis sp. nov. is described based on an adult antler, three cheek teeth, an astragalus, and a calcaneum. These specimens were discovered from the early Middle Miocene Dongxiang Formation of the Linxia Basin in Gansu Province, northwestern China. S. guangheensis is a small-sized crown-antlered deer, and its antler is broadly palmate, with six tines in the adult. It combines characters different from other species of the genus Stephanocemas, such as a moderately large palm, and superiorly orientated lateral tines. Its palmar base is a short semicircular column with a straight lateral margin and a shedding scar. This unclosed shedding scar is a shallow depression with dense spongy pores. S. guangheensis is more derived than S. aralensis and S. actauensis of the late Early Miocene, but more primitive than S. palmatus of the Middle Miocene. In the Linxia Basin, the Dongxiang Formation is poorly fossiliferous, so the discovery of S. guangheensis provides new evidence for the age estimation of this formation.