Therapsida

Reconstruction of Lemurosaurus pricei, by Theropsida.


Belongs within: Synapsida.
Contains: Dicynodontia, Cynodontia.

The Therapsida is the clade of all synapsids except for the basal 'pelycosaurs'. The earliest members of the clade are known from the Late Permian (Kemp 1988).

Synapomorphies (from Kemp 1988): Lateral temporal fenestra enlarged; supratemporal lost; shallow groove (external auditory meatus) on posterior face of squamosal; septomaxilla with long posterodorsal process; pineal foramen on raised boss; reflected lamina of angular greatly enlarged as thin sheet; jaw articulation shifted forwards; mobile basipterygoid articulation absent; interpterygoid vacuity reduced; palatal teeth reduced; paroccipital process extending more laterally than ventrally; vomer transversely widened between internal nares; transverse process of pterygoid shifted forward; no ossified intercentra in trunk; ossified sternum; cleithrum reduced, scapular blade narrow, coracoid and procoracoid reduced, screw-shaped glenoid absent; ilium expanded both anteriorly and posteriorly, acetabulum circular, fourth trochanter of femur absent; phalanges reduced.

<==Therapsida
    |  i. s.: Delphinognathus N85
    |         Lycaenops N85
    |         Microurania [Microuraniidae] TT05
    |           `--M. minima Ivakhnenko 1995 TT05
    |         Porosteognathus [Pristerognathidae] TT05
    |         Inostrancevia [Inostranceviidae] TT05
    |           `--I. uralensis Tatarinov 1974 TT05
    |         Scylacosuchus [Scylacosauridae] TT05
    |           `--S. orenburgensis TT05
    |         Moschorhinidae TT05
    |           |--Annatherapsidus petri (Amalitskii 1922) TT05
    |           `--Chthonosaurus velocidens V’yushkov 1955 TT05
    |--Biarmosuchia S03
    |    |  i. s.: Phthinosuchus K88
    |    |--Biarmosuchidae TT05
    |    |    |--Biarmosuchus S03 [incl. Biarmosaurus K88]
    |    |    `--Biarmosuchoides romanovi Tverdochlebova & Ivakhnenko 1994 TT05
    |    `--+--Hipposaurus S03
    |       `--Ictidorhinidae S03
    |            |--Lycaenodon Broom 1925 [incl. Hipposauroides Boonstra 1952] S03
    |            |    `--*L. longiceps Broom 1925 [incl. Hipposaurus rubidgei Broom 1940, *Hipposauroides rubidgei] S03
    |            `--+--Ictidorhinus martinsi S03
    |               `--Burnetiamorpha S03
    |                    |--Lemurosaurus pricei S03
    |                    `--Burnetiidae S03
    |                         |--Burnetia mirabilis S03
    |                         |--Proburnetia S03
    |                         `--Bullacephalus S03
    `--+--Eotitanosuchus [Eotitanosuchia] CL97
       `--Eutherapsida [Anomodontia] S03
            |--+--Dicynodontia S03
            |  `--Theriodontia [Therosauria] S03
            |       |--Gorgonopsia [Gennetotheria] S03
            |       `--Eutheriodontia HK01
            |            |--Cynodontia S03
            |            `--Therocephalia S03
            |                 |  i. s.: Lycosuchus HK01
            |                 |         Promoschorhynchus S03
            |                 |         Olivieria S03
            |                 |--Bauria HK01 [Bauriamorpha, Baurioidea K88]
            |                 `--Whaitsiidae K88
            `--Dinocephalia S03
                 |  i. s.: Rhopalodon TT05
                 |         Sinophoneus Cheng & Ji 1996 Cl97
                 |         Microsyodon orlovi CL97
                 |         Estemmenosuchus [Estemmenosuchidae] TT05
                 |--Stenocybus Cheng & Li 1997 [Stenocybusidae] CL97
                 |    `--*S. acidentatus Cheng & Li 1997 CL97
                 `--+--Ulemosaurus TT05 [Tapinocephalia CL97, Tapinocephalidae]
                    |    `--U. gigas TT05
                    `--Anteosauridae [Anteosauria] CL97
                         |--Titanophoneus adamanteus (Orlov 1958) CL97, TT05
                         |--Deuterosaurus jubilaei (von Nopcsa 1928) TT05
                         |--Syodon CL97
                         |--Anteosaurus CL97
                         `--Australosyodon CL97

*Type species of generic name indicated

REFERENCES

[CL97] Cheng Z. & Li J. 1997. A new genus of primitive dinocephalian - the third report on Late Permian Dashankou lower tetrapod fauna. Vertebrata PalAsiatica 35 (1): 35-43.

[HK01] Hopson, J. A., & J. W. Kitching. 2001. A probainognathian cynodont from South Africa and the phylogeny of nonmammalian cynodonts. Bulletin of the Museum of Comparative Zoology 156 (1): 5-35.

[K88] Kemp, T. S. 1988. Interrelationships of the Synapsida. In The Phylogeny and Classification of the Tetrapods, vol. 2. Mammals (M. J. Benton, ed.) pp. 1-22. Clarendon Press: Oxford.

[N85] Norman, D. 1985 (reprinted 2000). The Illustrated Encyclopedia of Dinosaurs. Salamander Books: London.

[S03] Sidor, C. A. 2003. The naris and palate of Lycaenodon longiceps (Therapsida: Biarmosuchia), with comments on their early evolution in the Therapsida. Journal of Paleontology 77 (5): 977-984.

[TT05] Tverdokhlebov, V. P., G. I. Tverdokhlebova, A. V. Minikh, M. V. Surkov & M. J. Benton. 2005. Upper Permian vertebrates and their sedimentological context in the South Urals, Russia. Earth-Science Reviews 69: 27-77.

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