Eutherapsida

Reconstruction of Ulemosaurus svijagensis, copyright Dmitry Bogdanov.

Belongs within: Therapsida.
Contains: Dicynodontia, Cynodontia.

The Eutherapsida are the clade of synapsids uniting modern mammals with the Permian Dinocephalia. Members of the clade are characterised by a bowing of the zygomatic arch and increase in size of the temporal fenestra, together with loss of the olecranon ulnae and reduction of the fifth pedal digit to three phalanges.

<==Eutherapsida [Anomodontia, Cryptodontia] S03
    |  i. s.: Theriognathus Broom 1920 C07, D07
    |           `--T. microps D07
    |         Endothiodon [Endothiodontia] C07
    |         Dromasauria R61
    |           |--Galeops R61
    |           |--Galechirus R61
    |           `--Galepus R61
    |--+--Dicynodontia S03
    |  `--Theriodontia [Therosauria] S03
    |       |  i. s.: Binaralia C07
    |       |           |--Lycosaurus C07
    |       |           `--Tigrisuchus C07
    |       |         Inostrancevia [Inostranceviidae] C07
    |       |           |--I. annae C07
    |       |           `--I. uralensis Tatarinov 1974 TT05
    |       |         Ericiolacerta Watson 1931 [Ericiolacertidae] D07
    |       |           `--E. parva D07
    |       |--Gorgonops C07 [Gennetotheria, Gorgonopsia S03, Tectinaralia]
    |       `--Eutheriodontia HK01
    |            |--Cynodontia S03
    |            `--Therocephalia S03
    |                 |  i. s.: Lycosuchus HK01
    |                 |         Promoschorhynchus S03
    |                 |--Bauria HK01 [Bauriamorpha, Baurioidea K88]
    |                 `--Whaitsiidae K88
    `--Dinocephalia S03
         |  i. s.: Rhopalodon TT05
         |         Sinophoneus Cheng & Ji 1996 CL97
         |         Microsyodon orlovi CL97
         |         Estemmenosuchus Tchudinov 1960 D07 [Estemmenosuchidae TT05]
         |           |--E. mirabilis D07
         |           `--E. uralensis D07
         |--Stenocybus Cheng & Li 1997 [Stenocybusidae] CL97
         |    `--*S. acidentatus Cheng & Li 1997 CL97
         `--+--Tapinocephalidae [Tapinocephalia, Tretospondylia] CL97
            |    |--Tapinocephalus C07
            |    `--Ulemosaurus Rjabinin 1938 TT05, D07
            |         |--U. gigas TT05
            |         `--U. svijagensis D07
            `--Anteosauridae [Anteosauria] CL97
                 |--Titanophoneus adamanteus (Orlov 1958) CL97, TT05
                 |--Deuterosaurus jubilaei (von Nopcsa 1928) TT05
                 |--Syodon CL97
                 |--Australosyodon CL97
                 `--Anteosaurus Watson 1921 D07
                      `--A. magnificus D07

*Type species of generic name indicated

REFERENCES

[C07] Case, E. C. 1907. Revision of the Pelycosauria of North America. Carnegie Institute of Washington Publication 55: 1–176, 35 pls.

[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.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[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: Benton, M. J. (ed.) The Phylogeny and Classification of the Tetrapods vol. 2. Mammals pp. 1–22. Clarendon Press: Oxford.

[R61] Romer, A. S. 1961. Synapsid evolution and dentition. In: Vandebroek, G. (ed.) International Colloquium on the Evolution of Lower and Non Specialized Mammals. Koninklijke Vlaames Academie voor Wetenschappen, Letteren en Schone Kunsten van Belgie—Klasse der Wetenschapen 1961 (1): 9–56.

[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.

Kannemeyeriiformes

Reconstruction of Kannemeyeria, copyright Dmitry Bogdanov.

Belongs within: Dicynodontia.

The Kannemeyeriiformes are a cosmopolitan clade of dicynodonts known from the Triassic, some members of which reached the size of a modern cow. Members of the clade are united by a markedly enlarged preacetabular expansion of the iliac blade, a distinctly offset caput femoris on the femur, and an olecranon ulnae formed by a separate ossification (Maisch 2000).

<==Kannemeyeriiformes
    |--Shansiodontidae M00
    |    |--Vinceria Bonaparte 1967 M00
    |    `--+--Rhinodicynodon Kalandadze 1970 M00
    |       `--+--Shansiodon Yeh 1959 M00
    |          `--Tetragonias Cruickshank 1967 M00
    |               `--T. njalilus M00
    `--+--Kannemeyeriidae M00
       |    |--Rabidosaurus Kalandadze 1970 M00
       |    |--Wadiasaurus Roy-Chowdhury 1970 M00
       |    |    `--W. indicus M00
       |    `--Kannemeyeria Seeley 1908 M00
       |         |--K. erithrea D07
       |         |--K. jenseni D07
       |         `--K. simocephala M00
       `--+--Dinodontosauridae [Dinodontosaurinae, Sinokannemeyeriini] M00
          |    |--Dinodontosaurus Romer 1943 M00
          |    `--+--Sinokannemeyeriinae M00
          |       |    |--Parakannemeyeria Sun 1960 M00
          |       |    `--Sinokannemeyeria Young 1937 M00
          |       `--Rechnisaurinae M00
          |            |  i. s.: Shaanbeikannemeyeria Cheng 1980 M00
          |            |--Rhadiodromus Efremov 1951 (see below for synonymy) M00
          |            `--+--Rechnisaurus Roy-Chowdhury 1970 M00
          |               `--Sangusaurus Cox 1969 M00
          |                    `--S. parringtonii NB17
          `--Stahleckeriidae M00
               |--Stahleckeriinae M00
               |    |--Angonisaurus Cox & Li 1983 M00
               |    |    `--A. cruickshanki NB17
               |    |--Stahleckeria von Huene 1925 [incl. Barysoma Cox 1965] M00
               |    |    `--S. potens von Huene 1935 [incl. S. lenzii Romer & Price 1944, Barysoma lenzii] M00
               |    `--Zambiasaurus Cox 1968 M00
               |         `--Z. submersus M00
               `--Placeriinae M00
                    |--Moghreberia Dutuit 1980 M00
                    |--Placerias Lucas 1904 M00
                    |    `--P. gigas M00
                    `--Ischigualastia Cox 1962 M00
                         `--I. jenseni M00

Kannemeyeriiformes incertae sedis:
  Jachaleria Bonaparte 1971 M00
  Dolichuranus Keyer 1973 M00
  Azarifeneria Dutuit 1989 (n. d.) M00
  Calleonasus Kalandadze 1986 (n. d.) M00
  Edaxosaurus Kalandadze 1986 (n. d.) M00
  Elatosaurus Kalandadze 1986 (n. d.) M00
  Nasoplanites Surkov 1999 M00
  Cristonasus Surkov 1999 M00
  Parvobestiola Surkov 1999 M00
  Planitorostris Surkov 1999 M00

Rhadiodromus Efremov 1951 [incl. Rhinocerocephalus Vjushkov 1969, Uralokannemeyeria Danilov 1971] M00

*Type species of generic name indicated

REFERENCES

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[M00] Maisch, M. W. 2000. Observations on Karoo and Gondwana vertebrates. Part 2: A new skull-reconstruction of Stahleckeria potens von Huene, 1935 (Dicynodontia, Middle Triassic) and a reconstruction of kannemeyeriiform phylogeny. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen 220 (1): 127–152.

[NB17] Nesbitt, S. J., R. J. Butler, M. D. Ezcurra, P. M. Barrett, M. R. Stocker, K. D. Angielczyk, R. M. H. Smith, C. A. Sidor, G. Niedźwiedzki, A. G. Sennikov & A. J. Charig. 2017. The earliest bird-line archosaurs and the assembly of the dinosaur body plan. Nature 544: 484–487.

Mammaliaformes

Left lower jaw of Shuotherium dongi, from Kielan-Jaworowska et al. (2002).

Belongs within: Cynodontia.
Contains: Mammalia.

The Mammaliaformes has been defined as the most exclusive group containing both crown mammals and Sinoconodon, and represents the broader group of animals generally considered as 'mammals'. Sinoconodon rigneyi is known from a partial skull from the lower Jurassic of China.

Synapomorphies (from Luo et al. 2002): Craniomandibular joint comprised of dentary condyle and squamosal glenoid; petrosal promontorium present; extensive development of a petrosal floor for the cavum epiptericum housing the trigeminal ganglion; separate tympanic aperture for prootic canal containing the prootic vein; fenestra vestibuli lacking thickened rim; hypoglossal foramen (cranial nerve XII) separated from the jugular foramen (cranial nerves IX, X, XI).

Mammaliaformes [Atheria, Eotheria, Triconodonta]
    |--Sinoconodon [Sinoconodontidae] KH14
    |    `--S. rigneyi JL06
    `--+--Adelobasileus cromptoni KH14, LA02
       `--+--Hadrocodium Luo, Crompton & Sun 2001 KH14, LCS01
          |    `--*H. wui Luo, Crompton & Sun 2001 LCS01
          `--+--Morganucodontidae [Morganucodonta] KH14
             |    |  i. s.: Brachyozostrodon LK-JC02
             |    |         Helvetiodon LK-JC02
             |    |         Wareolestes LK-JC02
             |    |         Indotherium LK-JC02
             |    |         Gondwanadon tapani LK-JC02, DDL04
             |    |         Indozostrodon LK-JC02
             |    |         Erythrotherium parringtoni LK-JC02, CJ78
             |    |         Eozostrodon Parrington 1941 D07
             |    |           `--E. parvus D07
             |    |--Megazostrodon Crompton & Jenkins 1968 RW12, A02
             |    |    `--M. rudnerae CJ78
             |    `--+--Dinnetherium Jenkins et al. 1983 RW12, CM99
             |       `--Morganucodon Kühne 1949 BW14, A02
             |            |--M. oehleri OB13 [=Eozostrodon oehleri CJ78]
             |            `--M. watsoni Kühne 1949 S05 [=Eozostrodon watsoni CJ78]
             `--+--Megaconus Zhou, Wu et al. 2013 BW14, ZW13
                |    `--*M. mammaliaformis Zhou, Wu et al. 2013 ZW13
                `--+--+--Mammalia KH14
                   |  `--+--Pseudotribos KH14
                   |     `--Shuotherium Chow & Rich 1982 LC07, K-JCL02 [Shuotheridia, Shuotheriidae, Yinotheria]
                   |          |--*S. dongi Chow & Rich 1982 K-JCL02
                   |          |--S. kermacki Sigogneau-Russell 1998 K-JCL02
                   |          `--S. shilongi Wang et al. 1998 K-JCL02
                   `--+--Woutersia Sigogneau-Russell 1983 JL06, A02 [Woutersiidae]
                      `--+--Tikitherium JL06
                         `--Docodonta JL06
                              |  i. s.: Peraiocynodon inexpectatus Simpson 1928 N10
                              |--+--Tashkumyrodon JL06
                              |  `--Tegotheriidae N10
                              |       |--Tegotherium JL06
                              |       `--Sibirotherium JL06
                              `--+--+--Borealestes JL06
                                 |  `--+--Docodon Marsh 1881 JL06, N10
                                 |     `--Haldanodon exspectatus BW14, OB13
                                 `--+--Dsungarodon JL06
                                    `--+--Castorocauda Ji, Luo et al. 2006 BW14, JL06
                                       |    `--*C. lutrasimilis Ji, Luo et al. 2006 JL06
                                       `--+--Simpsonodon JL06
                                          `--Krusatodon JL06

*Type species of generic name indicated

REFERENCES

[A02] Averianov, A. O. 2002. Early Cretaceous “symmetrodont” mammal Gobiotheriodon from Mongolia and the classification of “Symmetrodonta”. Acta Palaeontologica Polonica 47 (4): 705–716.

[BW14] Bi, S., Y. Wang, J. Guan, X. Sheng & J. Meng. 2014. Three new Jurassic euharamiyidan species reinforce early divergence of mammals. Nature 514: 579–584.

[CM99] Cifelli, R. L., & S. K. Madsen. 1999. Spalacotheriid symmetrodonts (Mammalia) from the medial Cretaceous (upper Albian or lower Cenomanian) Mussentuchit local fauna, Cedar Mountain Formation, Utah, USA. Geodiversitas 21 (2): 167–214.

[CJ78] Crompton, A. W., & F. A. Jenkins Jr. 1978. Mesozoic mammals. In: Maglio, V. J., & H. B. S. Cooke (eds) Evolution of African Mammals pp. 46–55. Harvard University Press: Cambridge (Massachusetts).

[DDL04] Datta, P. M., D. P. Das & Z.-X. Luo. 2004. A Late Triassic dromatheriid (Synapsida: Cynodontia) from India. Annals of Carnegie Museum 73 (2): 12–24.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[JL06] Ji, Q., Z.-X. Luo, C.-X. Yuan & A. R. Tabrum. 2006. A swimming mammaliaform from the Middle Jurassic and ecomorphological diversification of early mammals. Science 311: 1123–1127.

[K-JCL02] Kielan-Jaworowska, Z., R. L. Cifelli & Z.-X. Luo. 2002. Dentition and relationships of the Jurassic mammal Shuotherium. Acta Palaeontologica Polonica 47 (3): 479–486.

[KH14] Krause, D. W., S. Hoffmann, J. R. Wible, E. C. Kirk, J. A. Schultz, W. von Koenigswald, J. R. Groenke, J. B. Rossie, P. M. O'Connor, E. R. Seiffert, E. R. Dumont, W. L. Holloway, R. R. Rogers, L. J. Rahantarisoa, A. D. Kemp & H. Andriamialison. 2014. First cranial remains of a gondwanatherian mammal reveal remarkable mosaicism. Nature 515: 512–517.

[LA02] Long, J., M. Archer, T. Flannery & S. Hand. 2002. Prehistoric Mammals of Australia and New Guinea: One Hundred Million Years of Evolution. University of New South Wales Press: Sydney.

[LC07] Luo, Z.-X., P. Chen, G. Li & M. Chen. 2007. A new eutriconodont mammal and evolutionary development in early mammals. Nature 446: 288–293.

[LCS01] Luo, Z.-X., A. W. Crompton & A.-L. Sun. 2001. A new mammaliaform from the Early Jurassic and evolution of mammalian characteristics. Science 292: 1535–1540.

[LK-JC02] Luo, Z.-X., Z. Kielan-Jaworowska & R. L. Cifelli. 2002. In quest for a phylogeny of Mesozoic mammals. Acta Palaeontologica Polonica 47: 1–78.

[N10] Naish, D. 2010. Tetrapod Zoology: Book One. CFZ Press: Bideford (UK).

[OB13] O'Leary, M. A., J. I. Bloch, J. J. Flynn, T. J. Gaudin, A. Giallombardo, N. P. Giannini, S. L. Goldberg, B. P. Kraatz, Z.-X. Luo, J. Meng, X. Ni, M. J. Novacek, F. A. Perini, Z. S. Randall, G. W. Rougier, E. J. Sargis, M. T. Silcox, N. B. Simmons, M. Spaulding, P. M. Velazco, M. Weksler, J. R. Wible & A. L. Cirranello. 2013. The placental mammal ancestor and the post-K–Pg radiation of placentals. Science 339: 662–667.

[RW12] Rougier, G. W., J. R. Wible, R. M. D. Beck & S. Apesteguía. 2012. The Miocene mammal Necrolestes demonstrates the survival of Mesozoic nontherian lineage into the late Cenozoic of South America. Proceedings of the National Academy of Sciences of the USA 109 (49): 20053–20058.

[S05] Säilä, L. K. 2005. A new species of the sphenodontian reptile Clevosaurus from the Lower Jurassic of south Wales. Palaeontology 48 (4): 817–831.

[ZW13] Zhou, C.-F., S. Wu, T. Martin & Z.-X. Luo. 2013. A Jurassic mammaliaform and the earliest mammalian evolutionary adaptations. Nature 500: 163–167.

Last updated: 24 August 2018.

Therapsida

Reconstruction of Lemurosaurus pricei, by Theropsida.

Belongs within: Sphenacodontidae.
Contains: Eutherapsida.

The Therapsida are a clade including all synapsids except for the basal 'pelycosaurs', first known from the Middle Permian. Basal members of the clade include the Biarmosuchia, a group of small to medium-sized carnivores known from the Middle and Upper Permian of South Africa and Russia, characterised by the possession of uniformly small upper incisor teeth (Sidor 2003).

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
    |--+--Eotitanosuchus [Eotitanosuchia] CL97
    |  `--Eutherapsida S03
    `--Biarmosuchia S03
         |  i. s.: Phthinosuchus Efremov 1954 K88, D07 [Phthinosuchia]
         |           |--P. discors D07
         |           `--P. horissiaki D07
         |--Biarmosuchidae TT05
         |    |--Biarmosuchoides romanovi Tverdochlebova & Ivakhnenko 1994 TT05
         |    `--Biarmosuchus Chudinov 1960 S03, D07 [incl. Biarmosaurus K88]
         |         |--B. antecessor D07
         |         |--B. tchudinovi D07
         |         `--B. tener D07
         `--+--Hipposaurus Broom 1940 S03, D07
            |    |--H. boonstrai D07
            |    `--H. seelyi D07
            `--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

Therapsida incertae sedis:
  Delphinognathus N85
  Lycaenops Colbert 1948 D07
    |--L. angusticeps D07
    `--L. ornatus D07
  Microurania [Microuraniidae] TT05
    `--M. minima Ivakhnenko 1995 TT05
  Porosteognathus [Pristerognathidae] TT05
  Scylacosuchus [Scylacosauridae] TT05
    `--S. orenburgensis TT05
  Moschorhinidae TT05
    |--Annatherapsidus petri (Amalitskii 1922) TT05
    `--Chthonosaurus velocidens V’yushkov 1955 TT05
  Titanosuchus Owen 1879 D07
    |--T. cloeti D07
    `--T. ferox D07
  Jonkeria Van Hoepen 1916 D07
    |--J. boonstrai D07
    |--J. haughtoni D07
    |--J. ingens D07
    |--J. koupensis D07
    |--J. parva D07
    |--J. rossowi D07
    |--J. truculenta D07
    `--J. vanderbyli D07
  Moschops Broom 1911 D07
    |--M. capiensis D07
    |--M. koupensis D07
    |--M. oweni D07
    `--M. whaitsi D07
  Styracocephalus Houghton 1929 D07
    `--S. platyrhynchus D07

*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.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

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

Last updated: 27 August 2018.

Dicynodontia

Mounted skeleton of Lystrosaurus murrayi in the Muséum national d'histoire naturelle, Paris, photographed by FunkMonk.

Belongs within: Eutherapsida.
Contains: Kannemeyeriiformes.

The Dicynodontia are a group of herbivorous synapsids known from the the Late Permian to the Cretaceous, though they did not survive past the Late Triassic outside Australia. At their peak, they were the world's dominant herbivores. One genus, Lystrosaurus, included the most abundant terrestrial vertebrates in the earliest Triassic immediately following the end-Permian mass extinction. The name 'dicynodont' refers to the pair of large tusks that were generally the only teeth in their beaked jaws.

Synapomorphies (from Kemp 1988): Zygomatic arch dorsally displaced; dentaries fused at symphysis; articular surface of lower jaw sloping posteroventrally; horn developed on the jaws; intramandibular fenestra present; premaxillary secondary palate present.

<==Dicynodontia
    |--Kombuisia M00
    |--Myosaurus M00
    `--Pristerodontia M00
         |  i. s.: Odontocyclops M00
         |--Lystrosaurus Cope 1870 M00, D07 [Lystrosauridae]
         |    |--L. curvatus D07
         |    |--L. declivis D07
         |    |--L. georgi D07
         |    |--L. hedini D07
         |    |--L. mccaigi D07
         |    |--L. murrayi M00
         |    |--L. oviceps D07
         |    |--L. platycopes D07
         |    |--L. rajurkari D07
         |    |--L. robustus D07
         |    |--L. shichanggouensis D07
         |    `--L. weidenrichi D07
         `--+--+--Dinanomodon M00
            |  `--Kannemeyeriiformes M00
            `--Dicynodon Owen 1845 M00, D07 [Dicynodontidae]
                 |--D. bolorhinus D07
                 |--D. grimbeeki D07
                 |--D. lacerticeps M00
                 |--D. leontops D07
                 |--D. lissops D07
                 |--D. osborni D07
                 |--D. plateceps D07
                 |--D. trautscholdi D07
                 |--D. trigonocephalus D07
                 |--D. turpior D07
                 `--D. whaitsi D07

Dicynodontia incertae sedis:
  Cistecephalus Owen 1876 D07
    `--C. microrhinus D07
  Emydoses M00
  Otsheria K88
  Venyukovioidea TT05
    |  i. s.: Suminia getmanovi Ivakhnenko 1994 TT05
    `--Venyukoviidae TT05
         |--Ulemica efremovi Ivakhnenko 1996 TT05
         `--Venjukovia K88
  Aulacocephalodon peavoti N85
  Diictodon Owen 1876 D07
    `--E. feliceps D07

*Type species of generic name indicated

REFERENCES

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

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

[M00] Maisch, M. W. 2000. Observations on Karoo and Gondwana vertebrates. Part 2: A new skull-reconstruction of Stahleckeria potens von Huene, 1935 (Dicynodontia, Middle Triassic) and a reconstruction of kannemeyeriiform phylogeny. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen 220 (1): 127–152.

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

[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.

Last updated: 24 August 2018.

Cynodontia

Skull of Diademodon mastacus on display at the Museum für Naturkunde, Berlin, photographed by FunkMonk.

Belongs within: Eutherapsida.
Contains: Mammaliaformes.

The clade Cynodontia, incluing modern mammals and a number of related non-mammalian synapsids, was defined by Hopson & Kitching (2001) as the most inclusive clade including Mammalia and excluding Bauria. Though the group was ancestrally carnivorous, herbivory evolved among the cynodonts in the Gomphodontia and the Tritylodontidae (as well as several times within the mammals). Cynodonts are first known from the Late Permian, where they are represented by Dvinia and the Procynosuchidae. The remaining cynodonts form a clade Epicynodontia, defined as all taxa closer to mammals than Procynosuchidae and united by synapomorphies including a dentary-surangular dorsal contact midway between the postorbital bar and jaw joint, a coronoid process on the dentary extending above the middle of the orbit, four upper incisors and three lower incisors (Hopson & Kitching 2001).

Characters (from Hopson & Kitching 2001): Nasal-lacrimal contact present; postfrontal absent; prefrontal-postorbital contact present; ectopterygoid not in contact with maxilla; palatal exposure of maxilla behind canine greater than 20% distance from canine to posterior end of palatine; secondary palatal plate on maxilla and palatine; pterygoid flange without teeth; tabular extending around posttemporal foramen; groove on prootic extending from pterygoparoccipital foramen to trigemimal foramen; trigeminal nerve exiting via foramen between prootic and epipterygoid; posteroventral process on quadrate in posterior notch of squamosal; ascending process of epipterygoid greatly expanded; epipterygoid overlapping prootic; lateral flange present on prootic; epipterygoid in contact with frontal; double occipital condyles; stapedial foramen with dorsoventral orientation; dentary masseteric fossa present high on coronoid region; dentary overlap of surangular long; reflected lamina of angula spoon-shaped plate; incisor cutting margins smoothly ridged; canine serrations absent; postcanines with two or more cusps in line; lower anterior cingulum or cusp present; anterior process of ilium 1.0 to 1.5 times diameter of acetabulum; pubis between 1.5 and 1.0 times acetabular diameter.

<==Cynodontia
    |  i. s.: Chaliminia LCS01
    |         Lepagia DDL04
    |         Chronoperates paradoxus Fox, Youzwyshyn & Krause 1992 SFY02
    |--Dvinia HK01
    `--+--Procynosuchidae TT05
       |    |--Uralocynodon tverdochlebovae (Tatarinov 1987) TT05
       |    `--Procynosuchus Broom 1931 MH06, D07
       |         |--P. delaharpeae D07
       |         `--P. rubidgei D07
       `--Epicynodontia HK01
            |--Galesaurus HK01
            `--+--Thrinaxodon Seeley 1894 MH06, D07 [Thrinaxodontidae]
               |    `--T. liorhinus HK01
               `--Eucynodontia [Mammaliamorpha, Tritylodontoidea] HK01
                    |--Cynognathia HK01
                    |    |--Cynognathus Seeley 1895 HK01, D07 [Cynognathidae]
                    |    |    `--C. crateronotus HK01
                    |    `--Gomphodontia [Diademodontidae] HK01
                    |         |--Diademodon mastacus HK01
                    |         `--+--Trirachodon HK01
                    |            `--+--Pascualgnathus HK01
                    |               `--+--Scalenodon angustifrons HK01
                    |                  `--+--Luangwa HK01
                    |                     `--Traversodontidae D07
                    |                          |--Massetognathus Romer 1967 HK01, D07
                    |                          |    |--M. ochagaviae D07
                    |                          |    `--M. pascuali D07
                    |                          `--+--‘Scalenodon’ hirschoni HK01
                    |                             `--+--Exaeretodon HK01
                    |                                `--Gomphodontosuchus HK01
                    `--Probainognathia HK01
                         |--Lumkuia Hopson & Kitching 2001 [Lumkuiidae] HK01
                         |    `--*L. fuzzi Hopson & Kitching 2001 HK01
                         `--+--Ecteninion HK01
                            `--+--+--Probainognathus [Probainognathidae] LY11
                               |  |    `--P. jenseni HK01
                               |  `--+--Pachygenelus [Tritheledontidae] LY11
                               |     |    `--P. monus Watson 1913 OB13
                               |     `--+--Mammaliaformes LY11
                               |        |--+--Brasilodon MH06
                               |        |  `--Brasilitherium MH06
                               |        `--Tritylodontidae LY11
                               |             |  i. s.: Tritylodon longaevus Owne 1884 OB13
                               |             |--Kayentatherium KH14
                               |             |--Yunnanodon KH14
                               |             |--+--Bienotherium KH14
                               |             |  `--Oligokyphus Hennig 1922 KH14, D07
                               |             |       |--O. major [incl. O. minor] D07
                               |             |       `--O. triserialis D07
                               |             `--+--Bocatherium KH14
                               |                `--Bienotheroides KH14
                               `--Chiniquodontoidea DDL04
                                    |--Chiniquodontidae HK01
                                    |    |--Probelesodon HK01
                                    |    `--+--Aleodon brachyrhamphus HK01, NS10
                                    |       `--Chiniquodon von Huene 1936 MH06, D07
                                    |            |--C. magnificus D07
                                    |            |--C. sanjuanensis D07
                                    |            `--C. theotonicus D07
                                    `--+--+--Therioherpeton DDL04
                                       |  `--Charruodon DDL04
                                       `--Dromatheriidae DDL04
                                            |--Microconodon tenuirostris [=Dromatherium tenuirostris] DDL04
                                            |--Tricuspes DDL04
                                            |--Meurthodon DDL04
                                            |--Rewaconodon Datta, Das & Luo 2004 DDL04
                                            |    `--*R. tikiensis Datta, Das & Luo 2004 DDL04
                                            `--Pseudotriconodon DDL04
                                                 |--P. chatterjeei Lucas & Oakes 1988 DDL04
                                                 `--P. wildi DDL04

*Type species of generic name indicated

REFERENCES

[DDL04] Datta, P. M., D. P. Das & Z.-X. Luo. 2004. A Late Triassic dromatheriid (Synapsida: Cynodontia) from India. Annals of Carnegie Museum 73 (2): 12–24.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[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.

[KH14] Krause, D. W., S. Hoffmann, J. R. Wible, E. C. Kirk, J. A. Schultz, W. von Koenigswald, J. R. Groenke, J. B. Rossie, P. M. O'Connor, E. R. Seiffert, E. R. Dumont, W. L. Holloway, R. R. Rogers, L. J. Rahantarisoa, A. D. Kemp & H. Andriamialison. 2014. First cranial remains of a gondwanatherian mammal reveal remarkable mosaicism. Nature 515: 512–517.

[LCS01] Luo, Z.-X., A. W. Crompton & A.-L. Sun. 2001. A new mammaliaform from the Early Jurassic and evolution of mammalian characteristics. Science 292: 1535–1540.

[LY11] Luo, Z.-X., C.-X. Yuan, Q.-J. Meng & Q. Ji. 2011. A Jurassic eutherian mammal and divergence of marsupials and placentals. Nature 476: 442–445.

[MH06] Meng, J., Y. Hu, Y. Wang, X. Wang & C. Li. 2006. A Mesozoic gliding mammal from northeast China. Nature 444 (7121): 889–893.

[NS10] Nesbitt, S. J., C. A. Sidor, R. B. Irmis, K. D. Angielczyk, R. M. H. Smith & L. A. Tsuji. 2010. Ecologically distinct dinosaurian sister group shows early diversification of Ornithodira. Nature 464: 95–98.

[OB13] O'Leary, M. A., J. I. Bloch, J. J. Flynn, T. J. Gaudin, A. Giallombardo, N. P. Giannini, S. L. Goldberg, B. P. Kraatz, Z.-X. Luo, J. Meng, X. Ni, M. J. Novacek, F. A. Perini, Z. S. Randall, G. W. Rougier, E. J. Sargis, M. T. Silcox, N. B. Simmons, M. Spaulding, P. M. Velazco, M. Weksler, J. R. Wible & A. L. Cirranello. 2013. The placental mammal ancestor and the post-K–Pg radiation of placentals. Science 339: 662–667.

[SFY02] Scott, C. S., R. C. Fox & G. P. Youzwyshyn. 2002. New earliest Tiffanian (late Paleocene) mammals from Cochrane 2, southwestern Alberta, Canada. Acta Palaeontologica Polonica 47: 691–704.

[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.

Last updated: 24 August 2018.