Revision of the genus Halitherium (Mammalia: Sirenia) from the Oligocene of Europe

在莱茵-鲁尔地区下渐新世，对四具分离的、保存不完整的Sirenia骨骼进行了形态、系统和地层描述。经过广泛的比较研究，其中一个部分骨架可以明确地归属于美因茨盆地已知的Halitherium schinzi。有两个极其残缺的遗骸可归为盐石属；物种的确定是不确定的。另一个基于共同特征被确定为Halitherium的部分骨骼，由于存在一些个体特征而被认为是一个新种（Voß 2005：暂时被认为是Halitherium sp. K-H型）。目前认为在欧洲渐新世存在的有两种Halitherium: H. schinzi KAUP 1838和H. christoti FITZINGER 1842。两个分类群都表现出很大的种内变异（如KAUP 1855， LEPSIUS 1882, ABEL 1904, SlCKENBERG 1934）。此外，H. schinzi和H. christoli之间的差异很小（ABEL 1904）。因此，对莱茵-鲁尔地区遗骨的具体分配是困难的。本文在对来自德国、比利时和奥地利的古近系Sirenia的形态系统研究的基础上，对Sirenia进行了系统发育分析，重点讨论了Haffthenum属在Dugongidae中的系统地位。

Four disarticulated, incompletely preserved Sirenia skeletons were described morphologically, systematically and stratigraphically from the lower Oligocene of the Rhine-Ruhr area. After extensive comparative studies, one of the partial skeletons could clearly be assigned to Halitherium schinzi known from the Mainz Basin. Two extremely fragmentary remains could be assigned to the genus Halitherium; a species determination is uncertain. Another partial skeleton, determined as Halitherium based on common characters, was recognized as a new species (Voß 2005: provisionally as Halitherium sp. type K-H) because of the presence of some individual characteristics. At present, two species of Halitherium are regarded as valid within the European Oligocene, H. schinzi KAUP 1838 and H. christoti FITZINGER 1842. Both taxa show a great intraspecific variability (e.g. KAUP 1855, LEPSIUS 1882, ABEL 1904, SlCKENBERG 1934). In addition, the differences between H. schinzi and H. christoli are minimal (ABEL 1904). A specific allocation of the skeletal remains from the Rhine-Ruhr area was accordingly difficult. We propose a phylogentic analysis of the Sirenia based on morphological-systematic treatment of the sirenians from the Palaeogene of Germany, Belgium and Austria focusing on the systematic position of the genus Haffthenum within the Dugongidae.