Cranial anatomy and relationships of anew ctenodactyloid (Mammalia, Rodentia) from the early Eocene of Hubei Province, China

IVPP-IR > 中科院古脊椎所（2000年以后）

	Cranial anatomy and relationships of anew ctenodactyloid (Mammalia, Rodentia) from the early Eocene of Hubei Province, China
	Wible, JR; Wang, YQ; Li, CK; Dawson, MR; Wible, JR (reprint author), Sect Mammals, 5800 Baum Blvd, Pittsburgh, PA 15206 USA.
	2005
发表期刊	ANNALS OF CARNEGIE MUSEUM
ISSN	0097-4463
卷号	74 期号:2 页码:91—150
摘要	Two remarkably complete skulls and associated mandibles from the late early Eocene of the Yuhuangding Formation of Hubei Province, central China, are described as a new genus and species of rodent, Exmus mini, and referred to the early ctenodectyloid family Cocomyidae. This is a small rodent in the size range of the early Eocene Asian Cocomys. Dental characters that link Exmus with other cocomyids include: non-molariform P4; cheek teeth increasing in size posteriorly; lower molar ectolophid weak or absent; and lower molar hypoconulid distinct, enlarged on m3. Cranial characters linking Exmus and Cocomys include: skull shape and proportions, including a short rostrum and large orbit; sagittal crest absent; large optic canal, confluent between the orbits; and no petrosal shelf posterior to the caudal tympanic process of the petrosal. Differences from Cocomys are numerous and include: absence of conules on P4 and loss of the protoconule on the upper molars; tiny metacone and hypocone on P4; molariform p4: and auditory bulla tightly attached, rather than loose as in Cocomys. Exmus also displays a number of autapomorphies that distinguish it from all other Eocene rodents examined in this study, such as substantial orbital roof formed by lacrimal and frontal, and a suture between the parietals that is nearly completely fused. A phylogenetic analysis based on characters of the skull, mandible, and dentition supports the concept of two clades within the ingroups, one composed of Eocene paramyids, sciuravids, and theridomyids and the other composed of Bandaomys, Exmus, Cocomys, Tamquammys, Advenimus, and Yuomys as stem taxa to etenodactylids and hystricognaths. This dichotomy, which has been suggested by others prior to the discovery of Exmus, is here considered to represent an accurate assessment of Eocene rodent evolution and makes good paleogeographic sense. However, the desirability of adding more taxa to a phylogenetic analysis of early rodents is clearly recognized.
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收录类别	SCI收录
文献类型	期刊论文
条目标识符	http://119.78.100.205/handle/311034/3545
专题	中科院古脊椎所（2000年以后）
通讯作者	Wible, JR (reprint author), Sect Mammals, 5800 Baum Blvd, Pittsburgh, PA 15206 USA.
推荐引用方式 GB/T 7714	Wible, JR,Wang, YQ,Li, CK,et al. Cranial anatomy and relationships of anew ctenodactyloid (Mammalia, Rodentia) from the early Eocene of Hubei Province, China[J]. ANNALS OF CARNEGIE MUSEUM,2005,74(2):91—150.
APA	Wible, JR,Wang, YQ,Li, CK,Dawson, MR,&Wible, JR .(2005).Cranial anatomy and relationships of anew ctenodactyloid (Mammalia, Rodentia) from the early Eocene of Hubei Province, China.ANNALS OF CARNEGIE MUSEUM,74(2),91—150.
MLA	Wible, JR,et al."Cranial anatomy and relationships of anew ctenodactyloid (Mammalia, Rodentia) from the early Eocene of Hubei Province, China".ANNALS OF CARNEGIE MUSEUM 74.2(2005):91—150.