Mesozoic Mammals from Arizona: New Evidence on Mammalian Evolution

  title={Mesozoic Mammals from Arizona: New Evidence on Mammalian Evolution},
  author={Farish A. Jenkins and Alfred W. Crompton and William R. Downs},
  pages={1233 - 1235}
Knowledge of early mammalian evolution has been based on Old World Late Triassic-Early Jurassic faunas. The discovery of mammalian fossils of approximately equivalent age in the Kayenta Formation of northeastern Arizona gives evidence of greater diversity than known previously. A new taxon documents the development of an angular region of the jaw as a neomorphic process, and represents an intermediate stage in the origin of mammalian jaw musculature. 

First record of the tritylodontid Oligokyphus (Synapsida) from the Lower Jurassic of western North America

  • H. Sues
  • Geography, Environmental Science
  • 1985
ABSTRACT Teeth and cranial remains of a small tritylodontid have recently been discovered in the “Silty Facies” of the Kayenta Formation of northeastern Arizona. Based on the characteristic structure

A new non-mammalian eucynodont from the Chinle Formation (Triassic: Norian), and implications for the early Mesozoic equatorial cynodont record

Recently collected non-mammalian eucynodontian jaws from the middle Norian Blue Mesa Member of the Chinle Formation in northeastern Arizona shed light on the Triassic cynodont record from western equatorial Pangaea, indicating that the faunal dissimilarity previously recognized between the western and eastern portions of equatorialPangaea is overstated.

Relationships of the Liassic Mammals Sinoconodon, Morganucodon oehleri, and Dinnetherium

New skulls of Sinoconodon and Morganucodon oehleri are studied from the Liassic of Yunnan, China, and the Kayenta Formation of Arizona to address the lack of morphological information about the relationships of advanced cynodonts and early mammals.

Earliest Cretaceous Mammals from the Western United States

Mammalian diversity in North America shifted significantly during the Early Cretaceous, from archaic groups dominant in the well-sampled faunas of the Late Jurassic to advanced forms (including early

A New Mammaliaform from the Early Jurassic and Evolution of Mammalian Characteristics

A fossil from the Early Jurassic represents a new lineage of mammaliaforms, the extinct groups more closely related to the living mammals than to nonmammaliaform cynodonts, and shows that several key mammalian evolutionary innovations in the ear region, the temporomandibular joint, and the brain vault evolved incrementally through mammaliaform evolution and long before the differentiation of the living mammal groups.

Late Jurassic Mammals from Tendaguru, Tanzania, East Africa

Records of Mesozoic mammals are extremely rare in Africa. The only previous record from the Upper Jurassic of Africa is a fragmentary mandible without teeth of Brancatherulum tendagurense. Here I

A new species of the theropod dinosaur Syntarsus from the Early Jurassic Kayenta Formation of Arizona

The discovery of Syntarsus in North America adds significantly to the increasingly detailed resemblance of African and North American Early Jurassic terrestrial vertebrate faunas.

A new family of primitive mammal from the Mesozoic of western Liaoning, China

This animal has several derived characteristics, such as well-developed dentary/squamosal articulation, reduced number of tooth, differentiation of premolars and molars in postcanine teeth, and presence of a dorsal process of the premaxilla that is not in contact with the nasal.


Abstract We describe a new fossil crocodyliform archosaur from the Early Jurassic Kayenta Formation of the Navajo Nation that is surprisingly derived for so ancient a specimen. High-resolution X-ray

A Large Morganucodontan Mammaliaform from the Late Jurassic of Germany

Abstract An upper “triconodont” molar from the Late Jurassic (late Kimmeridgian) of the Langenberg Quarry in northern Germany is attributed to Storchodon cingulatus gen. et sp. nov. of



29] gives crown measurements for six M. watsoni and one M. oehleri molar series

  • ) gives crown lengths (N = 16) and widths (N = 11) of M. watsoni M2
  • 1971

A recently discovered skull of Sinoconodon provides definitive evidence that this form is a mammal, but the relation of the genus remains unclear

    in press) give a brief synopsis of the Kayenta fauna which they con--sider to be of Liassic age