[N] 2006 New Cretaceous Zalambdalestid mammal from China
Wood, C.B., Zan, S., Chen, J., Rougier, G. & Chaff, C. (2006) A new \\\\\\\"Middle\\\\\\\" Cretaceous Zalambdalestid mammal from Northeastern China. JVP 26(3) Abstracts pp. 141
Fossils from a new mid-Cretaceous locality near Gongzhuling City in Jilin Province, China, include two incomplete dentaries, which represent a newly described genus and species (Zhangolestes jilinensis) referable to the eutherian family Zalambdalestidae. Both dentaries possess an enlarged, procumbent first incisor combined with an interesting mosaic of both plesiomorphic and derived dental characters compared to the early zalambdalestid Kulbeckia kulbecke.
For example, the new specimens appear to show five premolars (including an almost fully molariform ultimate premolar) combined with only three incisors and a low but single-rooted canine. The trigonids on p5 and m1 are relatively open and not as compressed as in later zalambdalestids. Kulbeckia, from Turonian deposits in Uzbekistan has four premolars, and other than the typical procumbent incisor its anterior dentition is different in detail (e.g., four incisors plus double-rooted canine) compared to the Chinese material.
Cenomanian Bobolestes (now including Otlestes) has an almost fully molariform ultimate premolar but no sign of enlarged incisors. Other early eutherians such as Eomaia, Prokennelestes, and Montanalestes have a trenchant, non-molariform ultimate premolar.
Zhangolestes may therefore extend the range of certain, presumably derived eutherian characters to an earlier time than previously known. More work is needed on interbasinal correlation, but at present it seems unlikely that Zhangolestes could be younger than Cenomanian. The locality is in basin-margin outcrops of the Quantou Formation, which is widespread in the subsurface of Songliao Basin and which has been assigned ages ranging from Aptian to Cenomanian.
Songliao Basin is tectonically and sedimentologically distinct from the smaller but more numerous basins in western Liaoning. The Gongzhuling locality is likely to emerge as an important source of new information on “middle” Cretaceous vertebrates as additional mammalian, dinosaurian, and other specimens already collected are described from it.