New Basal Synapsid Supports Laurasian Origin for Therapsids

  title={New Basal Synapsid Supports Laurasian Origin for Therapsids},
  author={Jun Liu and Bruce S. Rubidge and Jin-ling Li},
The distant evolutionary ancestry of mammals is documented by a rich therapsid fossil record. While sphenacodontid synapsids are considered the sister-group of therapsids, the place of origin of therapsids is an enigma, largely because of a long standing morphological and temporal gap (Olson's Gap) in their fossil record. We describe a new large predatory synapsid, Raranimus dashankouensis gen. et sp. nov., from the Middle Permian of Dashankou in China which has a unique combination of… 

A re-assessment of the oldest therapsid Raranimus confirms its status as a basal member of the clade and fills Olson’s gap

CT scanning techniques are used to digitally reconstruct the bones and trigeminal canals of the snout of Raranimus in 3D and confirm that RarAnimus shares a high number of synapomorphies with more derived therapsids and is the only theraptor known so far to display a “pelycosaur”-like maxillary canal bearing a long caudal alveolar canal that gives off branches at regular intervals.

A faunivorous early sphenacodontian synapsid with a diastema

The diagnosis of this new form, Kenomagnathus scottae gen. et sp.

A new specimen of Biseridens qilianicus indicates its phylogenetic position as the most basal anomodont

A new well-preserved basal therapsid skull from the Xidagou Formation, Middle Permian of China, is identified as Biseridens qilianicus and is found to be the most basal anomodont, which highlights separate Laurasian and Gondwanan basal anamodont clades and suggests that dicynodonts had their origins in the Gondwana clade.

Adult morphology of the therocephalian Simorhinella baini from the middle Permian of South Africa and the taxonomy, paleobiogeography, and temporal distribution of the Lycosuchidae

The skull and partial skeleton of a large therocephalian from the uppermost Tapinocephalus Assemblage Zone of South Africa is described and forms the basis for a taxonomic re-evaluation of the Lycosuchidae as well as of the geographic and stratigraphic range of the family.

The Sphenacodontid Synapsid Neosaurus cynodus, and Related Material, from the Permo-Carboniferous of France

Sphenacodontid synapsids were major components of early Permian ecosystems. Despite their abundance in the North American part of Pangaea, they are much rarer in Europe. Among the few described

New Materials of the Enigmatic Dicynodont Abajudon kaayai (Therapsida, Anomodontia) from the Lower Madumabisa Mudstone Formation, Middle Permian of Zambia

ABSTRACT Dicynodonts were one of the most diverse and abundant clades of tetrapods from the Lopingian (late Permian) to the Late Triassic. Despite their ecological and biostratigraphic importance,

A new captorhinid reptile, Gansurhinus qingtoushanensis, gen. et sp. nov., from the Permian of China

The discovery of well-preserved captorhinid materials in the Middle Permian of China allows us to determine that the new taxon, Gansurhinus qingtoushanensis, gen. et sp.

“Pelycosaur”-Grade Synapsids: Introduction

  • R. Reisz
  • Environmental Science, Geography
  • 2014
Synapsids first appear in Late Carboniferous deposits in Nova Scotia, Canada. By the latest Carboniferous, they are the dominant vertebrates in terrestrial ecosystems and exceed their sister group

Re-evaluation of the historic Canadian fossil Bathygnathus borealis from the Early Permian of Prince Edward Island

The holotype and only known specimen of Bathygnathus borealis is a partial snout with maxillary dentition of a presumed sphenacodontid from the Lower Permian (Artinskian 283–290 Ma) redbeds of Prince

Early Evolutionary History of the Synapsida

Procrustes analysis of the two best-preserved specimens of these species allowed recognition of further shape differences: M. oligocynus has a taller but narrower cranium, taller snout, temporal opening more expanded laterally, pterygoid process located more anteriorly, and smaller suborbital vacuity.




Abstract:  The oldest records of mammal‐like therapsids in Laurasia are from the Ocher Complex of Russia and the Xidagou Formation of China, whereas in Gondwana they are restricted to the Eodicynodon

Evolutionary Patterns Among Permo-Triassic Therapsids*

Synapsids form the bulk of tetrapod diversity from Early Permian to Middle Triassic times and thus can provide critical information on the nature of the Permo-Triassic extinction in the terrestrial realm.

A global hiatus in the Middle Permian tetrapod fossil record

  • S. Lucas
  • Environmental Science, Geography
  • 2004
For about a half century, most vertebrate paleontologists have correlated the youngest Permian tetrapod assemblages in North America, which are from the San Angelo, Flowerpot and Chickasha formations

First record of a basal synapsid (‘mammal-like reptile’) in Gondwana

  • D. DilkesR. Reisz
  • Geography, Environmental Science
    Proceedings of the Royal Society of London. Series B: Biological Sciences
  • 1996
Elliotsmithia longiceps is a rare synapsid (‘mammal-like reptile’) from the middle part of the Tapinocephalus Assemblage Zone (Beaufort Group; Late Permian) of South Africa that belongs to the basal

A primitive anomodont therapsid from the base of the Beaufort Group (Upper Permian) of South Africa

Patranaomodonis primitive with respect to other anomodonts in having short palatal exposure of the premaxilla, an unreduced tabular, a slit-like interpterygoidal vacuity, a screw-shaped jaw articulation, and only three sacral vertebrae.

The origin and early radiation of the therapsid mammal‐like reptiles: a palaeobiological hypothesis

  • T. Kemp
  • Environmental Science, Geography
    Journal of evolutionary biology
  • 2006
An hypothesis is presented in which the origin of the therapsids resulted from a correlated progression of character evolution leading to higher levels of metabolic activity and homeostatic regulation of the body.

The osteology and relationships of Tetraceratops insignis, the oldest known therapsid

ABSTRACT Preparation and restudy of the Lower Permian synapsid Tetraceratops insignis demonstrate that it is related more closely to therapsids than to other Permo-Carboniferous synapsids. As the


A cladistic analysis of 10 therapsids, two outgroups, and 38 characters indicates that Lemurosaurus is the sister taxon to a clade including Bullacephalus, Proburnetia, and Burnetia and that it is most parsimonious to infer that burnetiamorphs originated in southern Africa.


Abstract The skull of the basal anomodont therapsid Anomocephalus africanus, from the Tapinocephalus Assemblage Zone of the Beaufort Group, Upper Permian of South Africa, is described in detail.

Cranial anatomy and phylogenetic position of Suminia getmanovi, a basal anomodont (Amniota: Therapsida) from the Late Permian of Eastern Europe

A cladistic analysis suggests that a «dicynodont-type» masticatory architecture, with an expanded adductor musculature and sliding jaw articulation, may have originated prior to the advent of the (Venyukovioidea+( Galeops +Dicynadontia)) clade.