山西保德第30地点发现了两种跳鼠化石,主要是三趾跳鼠Dipus fraudator,还有少量的五趾跳鼠Paralactaga cf.P.suni。这个跳鼠组合虽然种类不如内蒙古二登图动物群中的丰富,但其优势类群和组成比例都与后者非常相似。而与陕西蓝田灞河组发现的跳鼠组合相比,两者相差很大,后者以Protalactaga为主,虽然可能有一颗颊齿属于Paralactaga,但其明显比所有已知的种类原始。保德的跳鼠虽然只是该地区首批详细研究的小哺乳动物化石,但已经表明保德动物群和灞河动物群在小哺乳动物组成上也差异显著,进一步证实了灞河期和保德期动物群的截然不同,支持了灞河期的有效性。分析表明,跳鼠从10Ma以后都是与高冠食草动物伴生,显示出其耐旱性。因此,保德第30地点和相关层位应该是开阔草原环境,这与之前根据大哺乳动物组合及牙齿稳定同位素分析所恢复的生态环境一致。由于缺乏有效的地理隔离,保德地区第30地点和第49地点的生态差异显然不是空间上的,而是时间上的。
Two types of jerboa are found from Loc. 30 of Baode, Shanxi Province. The three-toed jerboa Dipus fraudator is the dominant taxon, accompanied with few teeth of the five-toed jerboa Paralactaga cf. P. suni. Although the diversity of this jerboa assemblage is not as high as that from Ertemte fauna, the two assemblages are fairly similar to each other. The jerboa assemblage from Baode is quite different to that from the Babe Formation, where the dominant member is Protalactaga. The Lantian assemblage also contains one tooth assigned to Paralactaga sp., but it is much primitive than any known species. The Baode jerboa assemblage then has no shared taxa with that of Lantian. Although the small mammals from Baode have not been fully studied, the difference betweenthe Bahean and Baodean small mammals is already evident. Jerboas are associated with high large mammal hypsodonty values from 10 Ma onwards and can be regarded as a proxy for relatively arid environments since the Late Miocene. The steppe environment suggested by these jerboas for Loc. 30 is consistent with the early analyses of the large mammals and the stable isotopes from ungulate teeth. The two different biomes traditionally recognized in the Baode area are separated temporally other than spatially.