伊朗新发现的中新世哺乳动物足迹的亲缘关系及其意义

伊朗晚中新世的几个地点新近发现了哺乳动物足迹化石。足迹化石在伊朗中北部分布在一套被称为上红组的厚层、混杂的泻湖-陆相地层序列的数个层位中;在伊朗北部的里海地区南部,则位于一套陆相沉积序列中。产自上红组的足迹以偶蹄动物类型为主,由于个体很小,可归入几种像羚羊一样大小的种;其他足迹则分别归入小型、中型和大型的鼬科和猫科食肉动物。产自伊朗北部的足迹化石主要为长鼻类,有些可能是犀牛,少数为偶蹄类足迹。根据上红组中发现的猫科动物(剑齿虎)足迹,可认为产足迹的地层年代为晚中新世,而产于伊朗北部古地中海边缘区沉积中的长鼻类足迹显示,地层的最大年龄为中新世最早期。这些足迹化石的发现填补了这一重要地区新近纪哺乳动物化石记录的空白。

AFFINITIES AND IMPLICATIONS OF NEW MIOCENE MAMMAL FOOTPRINTS FROM IRAN

Miocene mammalian footprints have been recently identified from several Late Miocene lo- calities in Iran.Tracksites occur exclusively throughout several stratigraphic levels of a thick,mixed-af- finity,lagoonal-terrestrial sequence known as the Upper Red Formation in north central Iron and within a continental series deposited in the southern Caspian area in north of the country.The tracks from the Upper Red Formation are mainly artiodactylan type,attributed to several gazelle sized species due to their small size,and other tracks attributed to small,medium and large sized mustelid and felid carni- vores.The fossil footprints from the north of Iran are mainly tracks of proboscideans,with some proba- ble rhino and a few artiodactyl prints.Based on the occurrence of felid (machairodontid) tracks in the Upper Red Formation,a Late Miocene age can be approved for the track-bearing strata,while probos- cidean tracks which occur within Paratethyan deposits in the north of the country suggest a maximum age of earliest Miocene for those levels.These tracks fill a gap in the record of Neogene mammals in this im- portant part of the world and contribute significantly to our knowledge of these faunas.