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.
Ecological niche/Guild: small terrestrial and semi-aquatic carnivores, insectivores, and piscivores
Modern equivalents: weasel, otter
Horizon: 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 ( 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
Taxonomic status - valid Family
Synonyms: Permocynodon Woodward 1932
Dvinia prima Amalitzky 1922.
Synonyms: Permocynodon sushkini Woodward 1932.
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).
Procynosuchus delaharpeae Broom 1937.
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.
Parathrinaxodon proops Parrington 1936.
Nanocynodon seductus Tatarinov 1968b.
Remarks: Tatarinov placed this species in the Galesauridae, but according to Heerdon and Rubidge it is more likely a juvenile procynosuchid.
|some Links and References|
Procynosuchidae Palaeos - Vertebrates - Toby White's excellent technical summary, lots of links. Also incorporates material from these pages
Dvinia prima - same content as preceeding page, but bigger photo
Carroll, R. L. Vertebrate paleontology and evolution. -W. H. Freeman and company, New York, 1988
Edwin H. Colbert, Evolution of the Vertebrates, 2nd edition, 1969, John Wiley & Sons
Barry Cox, R.J.G. Savage, Brian Gardiner; Dougal Dixon, 1988 Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals
James 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
James 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
James A. Hopson and James W. Kitching, 1972, "A Revised Classification of the Cynodonts (Reptilia; Therapsida), Paleontologica Africa, 14. 17-85
Palaeos Page (incorporates some of this material, plus a lot of additional material)