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Procynosuchidae


Dvinia prima

The procynosuchids were the earliest cynodonts. They flourished during the latest Permian (Cistecephalus and Daptocephalus Zones of South Africa and Tartarian/Zone IV of Russia), evolving from unknown bauriamorph/therocephalian ancestors. Like certain bauriamorphs they possessed a long series of small multicusped cheek teeth and a secondary palate. However, they also posessed certain cynodont features as well, such as a closed braincase which probably served generally to strengthen the skull and to protect the brain and middle ear cavity from pressures generated by the contraction of the increased mass of musculature. The teeth cheek teeth also had a much more complex cusp pattern than that of all but the latest bauriamorph therocephalians (i.e., the Bauridae). The complex cheek teeth and secondary palate show that the animal was able to chew and breathe at the same time (which most reptiles cannot - they swallow their food in gulps). The food was broken down in the mouth rather than the stomach. The modifications in the jaw and the flared zygomatic arch reflect increased differentiation of jaw musculature, principally the development of a separate masseter muscle.

The procynosuchids were almost certainly warm-blooded.

FAMILY PROCYNOSUCHIDAE Broom 1948

Includes: Silphedestidae Haughton and Brink 1954; Dviniidae Tatarinov 1968 a.
Ecological niche/Guild: small terrestrial and semi-aquatic carnivores, insectivores, and piscivores
Modern equivalents: weasel, otter
Horizon: link to palaeos com Late Permian: Daptocephalus Zone, Beaufort Series, of South Africa; Zone IV of Russia; Kawinga Formation of Tanzania.
Distribution: it is likely these animals had a worldwide ( link to palaeos com Pangea) distribution
preferred food: small dicynodonts, small diapsids, nyctiphruretids, procolophonids, fish, invertebrates
length: about 60 cm long
weight: less than a few kg
Metabolism: partially or completely endothermic
Potential Predators: small Gorgonopsia, Therocephalians
Ancestor: Basal Therocephalian
Replaced: small small Gorgonopsids and therocephalians
Replaced by: Galesauridae
Descendents: Galesauridae
Taxonomic status - valid Family

List of genera

Genus Dvinia Amalitzky 1922

Synonyms: Permocynodon Woodward 1932 Dvinia prima Amalitzky 1922. Synonyms: Permocynodon sushkini Woodward 1932.
Horizon: Upper Permian: Upper Tatarian deposits of Arkhangel'sk region, Russia.

Remarks: Among the most primitive Procynosuchids.

Many genera and species have been based on juvenile specimens of Procynosuchus, including all forms placed in the Family Silphedestidae by Haughton and Brink (1954).


Genus Procynosuchus Broom 1937


Procynosuchus
sketch by Bob Bakker


Synonyms: ? Cyrbasiodon Broom 1931; Paracynosuchus Broom 1940a; Mygalesaurus Broom 1942; Aelurodraco Broom and Robinson 1948b; Leavachia Broom 1948; Galeoplirys Broom 1948; Galecranium Broom 1948; Supliedestes Broom 1949; Protocynodon Broom 1949; Si'phedocynodon Brink 1951; Scalopocynodon Brink 1961.

Procynosuchus delaharpeae Broom 1937.


Horizon: Late Permian: Daptocephalus Zone of South Africa.
Size: 60cm long
type species

Remarks: Although one of the earliest and most primitive members of the cynodont group, Procynouchus was already specialized for a semi-aquatic lifestyle. The rear of its body and tail were more flexible than was usual among cynodonts, and could obviously be flexed from side to side, in a crocodile-style swimming motion. The tail vertebrae were flattened, to increase the surface area, making the tail a more efficient swimming organ. And the limbs were paddlelike, like those of a modern otter.

Many genera and species have been based on juvenile specimens of Procynosuchus, including all forms placed in the Family Silphedestidae by Haughton and Brink (1954).

Synonyms: ?Cyrbasiodon boycei Broom 1931; Procynosuchus rubidgei Broom 1938; Paracynosuchus rubidgei Broom 1940a; Nanictosuchus melinodon Broom 1940a; Mygalesaurus platyceps Broom 1942; Aelurodraco microps Broom and Robinson 1948b; Leavachia duvenhagei Broom 1948; Galeophrys kitchingi Broom 1948; Galecranium liorhynchus Broom 1948; Suphedestes polyodon Broom 1949; Protocynodon pricei Broom 1949; Suphedocynodon gymnoternporalis Brink 1951; Leavachia microps Brink and Kitching 1951a; Leavachia gracilis Brink and Kitching 1951a; Scalopocynodon gracilis Brink 1961.

Genus Parathrinaxodon Parrington 1936

Parathrinaxodon proops Parrington 1936.


Horizon: Upper Permian: Kawinga Formation of the Ruhuhu Valley, Tanzania.

Genus Nanocynodon Tatarinov 1968b.

Nanocynodon seductus Tatarinov 1968b.


Horizon: Upper Permian: Upper Tatarian of Russia.

Remarks: Tatarinov placed this species in the Galesauridae, but according to Heerdon and Rubidge it is more likely a juvenile procynosuchid.



some printed references some Links and References Web links

Palaeos link to palaeos com Procynosuchidae Palaeos - Vertebrates - Toby White's excellent technical summary, lots of links. Also incorporates material from these pages

web pagephotographsDvinia prima

web pagephotographsDvinia prima - same content as preceeding page, but bigger photo

printed referenceCarroll, R. L. Vertebrate paleontology and evolution. -W. H. Freeman and company, New York, 1988

printed referenceEdwin H. Colbert, Evolution of the Vertebrates, 2nd edition, 1969, John Wiley & Sons

printed referenceBarry Cox, R.J.G. Savage, Brian Gardiner; Dougal Dixon, 1988 Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals

printed referenceJames A. Hopson, "The Origin and Adaptive Radiation of Mammal-Like Reptiles and Non-Therian Mammals, Annals of the New York Academy of Sciences 167:199-216, 1969

printed referenceJames A. Hopson and Herbert R. Barghusen, "An Analysis of Therapsid Relationships", in The Ecology and Biology of Mammal-Like Reptiles ed. by Nocholas Hotton III, Paul D. MacLean, Jan J. Roth and E. Carol Roth, Smithsonian Institute Press, Washington and London, 1986, pp.83-106

printed referenceJames A. Hopson and James W. Kitching, 1972, "A Revised Classification of the Cynodonts (Reptilia; Therapsida), Paleontologica Africa, 14. 17-85



link to palaeos com Permian Period Therapsida Theriodontia


link to palaeos com Palaeos link to palaeos com Palaeos Page (incorporates some of this material, plus a lot of additional material)




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page uploaded 7 September 2000. Reposted and last modified 1 September 2005, links updated 16 January 2010