Problems of the Morphology of the Theriodonts (Reptilia)

Leonid P. Tatarinov


In scaloposaurians Karenites and Scalopognathus the mandibular coronoid process is not raised from the edge of the lower jaw and the external mandibular adductor is not attached to the summit of this process. Morphologically it is primitive state. High coronoid process was acquired by gorgonopsians and other theriodonts, including scaloposaurians, independently. In gorgonopsians, when mouth opened, the articular is rotated on the medial condyle of the quadrate; this movement is promoted by simultaneous rotation of the quadrate around its vertical axis. In therocephalians the quadrate is immovable, the articular is rotated on its lateral condyle. The division of the jaw joint on two condyles can be lost in scaloposaurians. The provisional connection of the stapes with the lower jaw, used for sound conduction, is established in some scaloposaurians. The basipterygoid articulation of some scaloposaurians is formed probably by the epipterygoid only, the carotid and Vidian canals are absent. In the evolution of theriodonts the palatal teeth are replaced with osseous ridges first, then these ridges are lost.


Theriodonts; Scaloposaurians; Permian; upper; Triassic; lower; morphology; skull; stapes

Full Text:



Barghusen H. R. (1968), «The lower jaw of cynodont (Reptilia, Therapsida) and the evolutionary origin of mammal-like adductor jaw musculature», Postilla Peabody Mus. Nat. Hist. Yale Univ., 116, 1 – 49.

Barghusen H. R. (1972), «The origin of the mammalian jaw apparatus», in: G. H. Schumacher (ed.), Morphology of the Maxillo-Mandibular Apparatus, VEB G. Thieme, Leipzig, pp. 26 – 32.

Barghusen H. R. and Hopson J. A. (1970), «Dentary-squamosal joint and the origin of mammals», Science, 168(9), 573 – 575.

Barry T. H. (1968), «Sound conduction in the fossil anomodont Lystrosaurus», Ann. S. Afr. Mus., 50(11), 275 – 281.

Boonstra L. D. (1953), «The lower jaw articulatory region in some pristerognathid therocephalians», Ann. S. Afr. Mus., 42(4), 54 – 63.

Boonstra L. D. (1954), «A scaloposaurid from the Tapinocephalus-zone», Ann. A. Mag. Nat. Hist. (Str. 12), 7(3), 54 – 63.

Brink A. S. (1982), «Illustrated bibliographical catalogue of the Synapsids. 1», Dept. Miner. Energy Affairs. Rep. S. Afr. Geol. Surv. Handb., 10, Pt. 1..

Brink A. S. (1988), «Illustrated bibliographical catalogue of the Synapsids. 2», Dept. Miner. Energy Affairs. Rep. S. Afr. Geol. Surv. Handb., 10, Pt. 2.

Broom R. L. (1932), The Mammal-Like Reptiles of South Africa and the Origin of Mammals, Witherby, London.

Bystrow A. P. (1955), «A gorgonopsian from the Upper Permian deposits on Volga River», in: Vopr. Paleontol. (Leningr.), 2, 7 – 18 [in Russian].

Carrol R. L. (1987), Vertebrate Paleontology and Evolution, W. H. Freeman and Co., New York.

Crompton A. W. (1955), «A revision of the Scaloposauridae with special reference to kinetism in the family», Navors. Nasion. Mus. Bloemfontein, 1(7), 149 – 183.

Crompton A. W. (1963a), «On the lower jaw of Diarthognathus and the origin of the mammalian lower jaw», Proc. Zool. Soc. London, 140(8), 697 – 750.

Crompton A. W. (1963b), «The evolution of the mammalian jaw», Evolution, 17(5), 431 – 439.

Crompton A. W. (1972), «The evolution of the jaw articulation of cynodont», in: K. A. Joysey and T. S. Kemp (eds.), Studies in Vertebrate Evolution, Winchester Press, New York, pp. 231 – 251.

Crompton A. W. and Hylander W. L. (1986), «Changes in mandibular function following the acquisition of a dentary-squamosal jaw articulation», in: N. Hotton III, P. D. MacLean, J. J. Roth, and C. E. Roth (eds.), The Ecology and Biology of Mammal-Like Reptiles, Smithsonian Inst. Press, Washington – London, pp. 263 – 282.

Findlay G. H. (1968), «On the scaloposaurid skull of Oliveria parringtoni Brink, with notion the origin of hair», Palaeontol. Afr., 11, 47 — 60.

Hartmann-Weinberg A. P. (1938), «Gorgonopsids of the USSR as an indicators of time», Vopr. Paleontol. (Moscow), 4, 47 – 87 [in Russian].

Kemp T. S. (1969), «On the functional morphology of the gorgonopsid skull», Phil. Trans. Roy. Soc. London, 256(801), 1 – 83.

Kemp T. S. (1972), «The jaw articulation and musculature of the whaitsiid Therocephalia», in: K. A. Joysey and T. Kemp (eds.), Studies in Vertebrate Evolution, Winchester Press, New York, pp. 213 – 230.

Kemp T. S. (1979), «The primitive cynodont Procynosuchus: functional anatomy of the skull and relationships», Phil. Trans. Roy. Soc. London, 285(1005), 73 – 122.

Kemp T. S. (1982), Mammal-Like Reptiles and the Origin of Mammals, Acad. Press, London, New York, etc..

Mendrez Ch. H. (1972), «On the skull of Regisaurus jacobi, a new genus and species of Bauriamorpha Watson and Romer, 1956 (Scaloposauria Boonstra 1953) from the Lystrosaurus zone of South Africa», in: K. A. Joysey and T. S. Kemp (eds.), Studies in Vertebrate Evolution, Winchester Press, New York, pp. 192 – 212.

Mendrez Ch. H. (1975), «Principeles variation du palais chez les therocephalen sud-africains (Pristerosauria et Scaloposauria) au cours du Permien superieur et Trias inferieur», in: Colloq. Int. C.N.R.S., Paris, 4 – 9 juin 1973. No. 218, «Problemes actuels du paleontologie at evolution des vertebres», pp. 379 — 408.

Mendrez-Carroll Ch. H. (1979), «Nouvelle etude du crane du type de Scaloposaurus constrictus Owen, 1876, specimen jeune, Therocephalia, Scaloposauria, Scaloposauridae, de la zone a Cistecephalus (Permien superieur) d’Afrique australe», Bull. Mus. Natl. Hist. Nat. (Paris) 4 ser., 1C(3), 155 – 201.

Orlov J. A. (1958), «Predatory deinocephalians of the Isheev fauna (titanosuchians) [Khishchnye deinotsefaly fauny Isheeva (titanosukhi)]», in: Trudy Paleontol. Inst. AN SSSR. Vol. 72, Nauka, Moscow [in Russian].

Parrington F. R. (1955), «On the cranial anatomy of some gorgonopsids and the synapsid middle ear», Proc. Zool. Soc. London, 125(1), 1 – 40.

Romer A. S. (1956), Osteology of the Reptilia, Univ. Chicago Press, Chicago.

Romer A. S. and Price L. W. (1940), «Review of the Pelycosauria», Geol. Soc. Am. Spec. Pap., 28(X), 1 – 538.

Sun Ailin and Hou Lian-hai (1981), «Hazhenia, a new genus of Scaloposauria», Acta Sci. Sinica, 20(4), 297 – 311.

Tatarinov L. P. (1966), «Basipterygoid articulation and vidian canals in therapsids», Paleontol. Zh., No. 1, 101 – 115 [in Russian].

Tatarinov L. P. (1968), «Morphology and systematics of the Northern Dvina cynodonts (Reptilia, Therapsida; Upper Permian)», Postilla Peabody Mus. Nat. Hist. Yale Univ., 126, 1 – 51.

Tatarinov L. P. (1974), «Theriodonts of the USSR», in: Trudy Paleontol. Inst. AN SSSR. Vol. 143, Nauka, Moscow, p. 252 [in Russian].

Tatarinov L. P. (1976), Morphological Evolution of the Theriodonts and General Problems of Phylogenetics, Nauka, Moscow [in Russian].

Tatarinov L. P. (1993a), «On the crossopterygian features in the skull of the Late Permian therocephalian Hexacynodon perlunensis (Reptilia, Theriodontia)», Dokl. Ross. Akad. Nauk, 332(1), 124 – 126 [in Russian].

Tatarinov L. P. (1993b), «On the unusual peculiarities in morphology of the head in therocephalian Hexacynodon perlunensis», Russ. J. Herpetol., 1(1), 5 – 16.

Tatarinov L. P. (1995a), «A new Upper Permian therocephalian Viatkosuchus sumini from the Kirov region», Paleontol. Zh., No. 1, 66 – 71 [in Russian].

Tatarinov L. P. (1995b), «A new ictidosuchid Karenites ornamentatus (Theriodontia) from the Upper Permian of the Kotel’nich locality in the Kirov region», Russ. J. Herpetol., 2(1), 18 – 33.

Tatarinov L. P. (1998), «New data about Scalopognathus multituberculatus — a theriodont from the Lower Triassic of the Pechora River Basin (Komi Republic)», Paleontol. Zh., No. 1, 67 – 75 [in Russian].

Tatarinov L. P. (2000), «New data on scaloposaurians from the Upper Permian of Kotel’nich, Kirov region», Paleontol. Zh., in press [in Russian].

Toerien M. J. (1963), «The sound-conducting systems of lizards without tympanic membranes», Evolution, 17(5), 540 – 547.

Vjushkov B. P. (1955), «Therocephalians of the Soviet Union», in: Trudy Paleontol. Inst. AN SSSR. Vol. 32, Moscow, pp. 128 – 175 [in Russian].

Vjushkov B. P. (1964), «Superfamily Scylacosauroidea (= Therocephalia). Therocephalians», in: J. A. Orlov (ed.), The Basis of Paleontology [Osnovy Paleontologii], Moscow, pp. 275 – 280 [in Russian].

Vorobjeva E. I. (1977), «Morphology and peculiarities of evolution of crossopterygian fishes», in: Trudy Paleontol. Inst. AN SSSR, Vol. 163, Moscow, Nauka [in Russian].

Watson D. M. S. (1931), «On the skeleton of a bauriamorth reptile», Proc. Zool. Soc. London, 3, 1163 – 1205.



  • There are currently no refbacks.

You can subscribe to the print or electronic version of the journal on the site of EastView Company. If you have any questions, please write to the email