摘要
描述了2005年和2010年采自青海柴达木盆地中部地区大红沟背斜和东陵丘背斜的河狸科化石,其中大红沟的材料包括1件下颌、l件门齿和6枚零散颊齿,被归人中国北方中中新世常见的通古尔单沟河狸（Monosaulax tungurensis）;其牙齿尺寸较小,门齿的釉质层圆凸,表面光滑;颊齿齿冠低,前臼齿大于臼齿;颊齿的（下）次沟向下延伸几乎到达牙齿基部,所有褶沟均填充白垩质;P4的前沟明显深于中沟和后沟;无次生的小坑发育.东陵丘的材料仅有1枚上臼齿,尺寸较大,冠面仅具4条褶（沟）,褶沟有厚实的白垩质填充,次沟向下延伸近至齿根,唇侧沟深浅不一,被归入上新世早期的安氏河狸（Castor anderssoni）.河狸科多营半水栖生活,生活于林地的湖或河流边,具有非常强的环境指示意义.柴达木盆地内新近纪河狸科化石的发现,进一步证明在中中新世和上新世早期,盆地的中部地区仍存在较大的水体和较多的林木.
We describe the Neogene beavers discovered at south wings of Donglingqiu（Fig.1 and 5）and Dahonggou（Fig.1 and 4）anticlines of central Qaidam Basin, northern Tibetan Plateau, which are 70km and 43km from the northeastern Dachaidan County seat, respectively.Samples from Dahonggou include a broken mandible（IVPP V 20131） from loc.CD1003（37°30＇29.4＂N, 95°08＇39.4＂E, 3248±12m above sea level（a.s.l.））, a lower incisor and six isolated cheek teeth（V 20132.1~7）from loc.CD1002（37°30＇30.2＂N, 95°08＇39.6＂E, 3256.9±28m a.s.l）（see Fig.3A^3G）.They are referred to Middle Miocene Monosaulax tungurensis Li, 1963 by having convex and smooth enamel surface of the lower incisor, low crown cheek teeth, premolar larger than molars, strias and striids filled with cement, hypostrias and hypostriids nearly extending to base of the teeth, parastria on P4 extending longer than mesostria and metastia, hypoflexids seated oppositely to metafossettid, and a lack of subparafossette and proparafossettid.On the other hand, the only upper molar（IVPP V20130, see Fig.3H） from the loc.CD0511（37°29＇26.4＂N, 94°41＇58.9＂E, 2941m a.s.l.） of Donglingqiu Anticline is referred to Early Pliocene Castor anderssoni（Schlosser, 1924）by having large size, four flexuses or strias filled with thick cement on cheek teeth, hypostria nearly extending to the tooth base and buccal strias in different length.
Judging by fauna correlation, the age of Monosaulax tungurensis from Dahonggou should be restricted within the Middle Miocene Tunggurian of the Chinese Land Mammalian Age or Stage and around 12.5Ma.It is inconsistence with paleomagnetic chronolgy of the neighboring Nanhonggou section by Lu et al.（2009）（see Fig.4）.The strata bearing Castor anderssoni in Donglingqiu section roughly corresponds to the middle part of the Shizigou Formation, which yields a Pliocene ostracod complex documented by Sun Zhencheng（unpublished data）（see Fig.5）.The length of strias extending to the tooth bas
出处
《第四纪研究》
CAS
CSCD
北大核心
2015年第3期584-595,共12页
Quaternary Sciences
基金
国家自然科学基金重点项目（批准号：41430102）、中国科学院战略性先导科技专项项目（批准号：XDB03020104）、国家重点基础研究发展规划项目（973项目）（批准号：2012CB821904）、美国自然科学基金项目（批准号：EAR.0446699,0444073,0958704和1227212）和国家自然科学基金面上项目（批准号：41472002）共同资助
