封面说明：集宁晚中新世三趾马动物群复原图。蒙古高原新生代火山活动形成大面积展布的玄武岩层。在晚中新世玄武岩喷发间隙，这里的环境主要为干旱的开阔草原，以草本植物为食的三趾马、古麟、小羚羊、瞪羚和捕食者剑齿虎等动物在此栖息。本次在内蒙古集宁发现的化石层正好夹于两层玄武岩之间。玄武岩样品的K-Ar测年结果表明这个动物群的时代介于7.2~6.8 Ma，这是对我国三趾马动物群时代的首次精确测年。通过对比集宁与中国北方其他三趾马动物群的物种组成相似性，可以进一步确定各动物群时代。详见本期王倩等人文。(绘图：史爱娟)
Cover image：The reconstruction of the Late Miocene Hipparion fauna in Jining District. Volcanic activity on the Mongolian plateau formed large area of basalts during the Cenozoic era. The environment here was supposed to be a dry and open grassland with inhabitation of some herbivores such as Hipparion, Palaeotragus, Dorcadoryx, Gazella and predators such as saber toothed cats etc. during the Late Miocene. The fossil layers discovered in the Jining District, Nei Mongol are sandwiched between two layers of basalt. The K-Ar dating of the basalt samples constrained the age of the Jining Hipparion fauna to be 7.2-6.8 Ma. This is the first precise numerical dating of the well known Hipparion fauna in China, which can be used as an inference for the age of other Hipparion faunas in North China by comparing the faunal similarity. See details in the paper of Wang et al. (illustrated by Shi Ai-Juan)
