新疆准噶尔盆地北缘始新世Advenimus梳趾鼠类一新种(英文)

A NEW SPECIES OF ADVENIMUS (RODENTIA, MAMMALIA) FROM THE EOCENE OF NORTHERN JUNGGAR BASIN OF XINJIANG, CHINA

依据采自新疆福海县哈拉玛盖乡萨尔多依腊地点第三系的化石，建立了一个啮齿类新种 乌伦古河陌生鼠 Ａｄｖｅｎｉｍｕｓ ｕｌｕｎｇｕｒｅｎｓｉｓ ｓｐ． ｎｏｖ．。 Ａ ｕｌｕｎｇｕｒｅｎｓｉｓ为一中等大小的早期梳趾 鼠类，齿低冠，下齿列颊齿由前向后逐渐增大；上、下第４前臼齿均次臼齿化；Ｐ４具发育的前齿 带，前、后尖发育但紧相邻，分别以完整的原脊、后脊与原失相连。Ｍ２前齿带亦发育，前、后尖与 分别连接它们的原、后脊无明显界限，不具小尖，次尖小于原尖。下颊齿齿尖较钝。ｐ４跟座较三 角座宽；下臼齿下外脊和下中尖弱；下次脊弱，伸至下次小尖前基部．眶前孔据推测较大。与其 他早期梳趾鼠相比，新疆标本与发现于内蒙古、湖北以及吉尔吉斯的Ａｄｖｅｎｉｍｕｓ最为接近。在已 确认的Ａｄｖｅｎｉｍｕｓ的两个种中，Ａ．ｕｌｕｎｇｕｒｅｎｓｉｓ在ｐ４跟座宽于三角座且缺前齿带，颊齿齿尖较 钝、下后失前倾、下次脊弱且伸至下次小尖前基部、下中失较弱、跟座开阔等特点方面有别于Ａ． ｂｕｒｋｅｉ。以齿尖较纤细，下后尖前倾，下原尖后臂弱，下中尖弱小，下次尖与下次小尖连接较强等 与Ａ． ｈｕｐｅｉｅｎｓｉｓ相区别。 Ａｄｖｅｎｉｍｕｓ原来的两个种都仅以下齿列为依据。

A new species of 4dvenimus, A. ulungurensis sp. nov., is described based on dental specimens collected from Tertiary beds on the south bank of the Ulungur River in northem Junggar Basin of the Xinjiang Uygur Autonomous Region of China. These specimens represent the first record of ctenodactyloids in Xinjiang. Correlations with distributions of other species of Alvenimus indicate that the bed yielding the Xinjiang fossils is of probably early Eocene in age.