Ptilodontoidea

Skull of Ptilodus mediaevus, copyright Nobu Tamura.

Belongs within: Cimolodonta.

The Ptilodontoidea are a group of multituberculate mammals known from the Upper Cretaceous to the Eocene of Eurasia and North America, characterised by a very large, arcuate lower rear premolar protruding dorsally above the level of the molars (Kielan-Jaworowska & Hurum 2001).

Characters (from Kielan-Jaworowska & Hurum 2001): Dental formula 2.0.4.2/1.0.2.2; enamel usually microprismatic (gigantoprismatic in Cimolodon); I2 probably single-cusped, I3 placed on margin of premaxilla; lower incisor usually gracile, completely covered with enamel (robust with limited enamel band in Neoliotomus); P4 elongated, shaped as isosceles triangle in lateral view, protruding ventrally over level of anterior premolars and molars; p4 very large, arcuate, strongly protruding dorsally over level of molars; molars with ornamentation of grooves and ridges, cusps tending to coalesce. Snout wide, gently incurved in front of zygomatic arches. Frontals small, pointed posteriorly.

<==Ptilodontoidea
    |--Cimolodontidae K-JH01
    |    |--Anconodon Jepsen 1940 K-JH01
    |    |--Liotomus Cope 1884 K-JH01
    |    `--Cimolodon Marsh 1889 K-JH01
    |         `--C. electus K-JH01
    `--+--Neoliotomus Jepsen 1930 K-JH01
       `--+--Ptilodontidae [Chirogidae] K-JH01
          |    |--Kimbetohia Simpson 1936 K-JH01
          |    |--Prochetodon Jepsen 1940 K-JH01
          |    |--Baiotomeus Krause 1987 SFY02
          |    |    |--B. douglassi (Simpson 1935) SFY02
          |    |    |--B. lamberti Krause 1987 SFY02
          |    |    `--B. russelli Scott, Fox & Youzwyshyn 2002 SFY02
          |    `--Ptilodus Cope 1881 SFY02
          |         |--P. douglassi Simpson 1935 S35b
          |         |--P. fractus Dorr 1952 SFY02
          |         |--P. gidleyi Simpson 1935 S35b
          |         |--P. gnomus Scott, Fox & Youzwyshyn 2002 SFY02
          |         |--P. kummae Krause 1977 SFY02
          |         |--P. mediaevus Cope 1881 SFY02
          |         |--P. montanus Douglass 1908 [incl. P. admirabilis Hay 1930, P. gracilis Gidley 1909 (preoc.)] S35b
          |         |--P. sinclairi Simpson 1935 S35b
          |         |--P. trovessartianus S35b
          |         |--P. tsosiensis Sloan 1981 SFY02
          |         `--P. wyomingensis D07
          `--Neoplagiaulacidae K-JH01
               |--Xyronomys Rigby 1980 K-JH01
               |--Cernaysia Vianey-Liaud 1986 K-JH01
               |--Krauseia Vianey-Liaud 1986 K-JH01
               |--Mesodma Jepsen 1940 K-JH01
               |--Mimetodon Jepsen 1940 K-JH01
               |--Mesodmops Tong & Wang 1994 K-JH01
               |--Xanclomys Rigby 1980 K-JH01
               |--Neoplagiaulax Lemoine 1882 K-JH01
               |    `--N. hazeni K-JH01
               |--Parectypodus Jepsen 1930 K-JH01
               |    |--P. jepseni Simpson 1935 S35b
               |    |--P. laytoni K-JH01
               |    |--P. simpsoni S35b
               |    `--P. tardus S35b
               `--Ectypodus Matthew & Granger 1921 K-JH01
                    |--*E. musculus Matthew & Granger 1921 S35a
                    |--E. cochranensis S35b
                    |--E. grangeri Simpson 1935 S35b
                    |--E. russelli Simpson 1935 S35b
                    |--E. silberlingi Simpson 1935 S35b
                    `--E. tardus K-JH01

*Type species of generic name indicated

REFERENCES

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

[K-JH01] Kielan-Jaworowska, Z., & J. H. Hurum. 2001. Phylogeny and systematics of multituberculate mammals. Palaeontology 44 (3): 389–429.

[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.

[S35a] Simpson, G. G. 1935a. The Tiffany fauna, Upper Paleocene. I.—Multituberculata, Marsupialia, Insectivora, and ?Chiroptera. American Museum Novitates 795: 1–19.

[S35b] Simpson, G. G. 1935b. New Paleocene mammals from the Fort Union of Montana. Proceedings of the United States National Museum 83 (2981): 221–244.

Cimolodonta

Lower jaw of Cimexomys, from Palaeos.

Belongs within: Multituberculata.
Contains: Ptilodontoidea.

The Cimolodonta are a group of multituberculate mammals known from the Early Cretaceous to the Eocene, including all multituberculates to survive the end of the Cretaceous (Kielan-Jaworowska & Hurum 2001).

Characters (from Kielan-Jaworowska & Hurum 2001): Enamel prismatic; dental formula 2.0.1–4.2/1.0.1–2.2; I1 absent, I2 single- or two-cusped, I3 small, single-cusped; p1 and p2 absent, p3, if present, peg-like, non-functional; p4 primitively arcuate with oblique ridges, single or no posterobuccal cusp present.

Cimolodonta [Boffiini]
    |--Barbatodon Râdulescu & Samson 1986 K-JH01
    |--Dakotamys Eaton 1995 K-JH01
    |    `--D. malcolmi K-JH01
    |--Bryceomys Eaton 1995 K-JH01
    |    `--B. fumosus K-JH01
    |--Paracimexomys Archibald 1982 K-JH01
    |    |--P. crossi K-JH01
    |    `--P. robinsoni K-JH01
    |--Cimexomys Sloan & van Valen 1965 K-JH0
    |    |--C. antiquus D07
    |    |--C. gratus D07
    |    |--C. gregoryi D07
    |    |--C. hausoi D07
    |    |--C. judithae K-JH01
    |    |--C. magnus D07
    |    `--C. minor D07
    `--+--Boffius Vianey-Liaud 1979 [Boffiidae] K-JH01
       |--Ptilodontoidea K-JH01
       `--Taeniolabidoidea K-JH97
            |--Cimolomyidae K-JH01
            |    |--Meniscoessus Cope 1882 K-JH01
            |    |--Cimolomys Marsh 1889 K-JH01
            |    |--Essonodon Simpson 1927 K-JH01
            |    `--Buginbaatar Kielan-Jaworowska & Sochava 1969 [Buginbaatarinae] K-JH01
            |         `--B. transaltaiensis Kielan-Jaworowska & Sochava 1969 K-JH97
            `--+--Djadochtatherioidea K-JH01
               |--Kogaionidae K-JH01
               |    |--Hainina Vianey-Liaud 1979 K-JH01
               |    `--Kogaionon Râdulescu & Samson 1996 K-JH01
               |--Eucosmodontidae K-JH01
               |    |--Eucosmodon Matthew & Granger 1921 K-JH01
               |    |--Stygimys Sloan & van Valen 1965 K-JH01
               |    `--Clemensodon Krause 1992 K-JH01
               |--Microcosmodontidae K-JH01
               |    |--Microcosmodon Jepsen 1930 K-JH01
               |    |--Pentacosmodon Jepsen 1940 K-JH01
               |    `--Acheronodon Archibald 1982 K-JH01
               `--Taeniolabididae K-JH01
                    |--Prionessus Matthew & Granger 1925 K-JH01
                    |--Sphenopsalis Matthew, Granger & Simpson 1928 K-JH01
                    |--Lambdopsalis Chow & Qi 1978 K-JH01
                    |    `--L. bulla K-JH97
                    |--Catopsalis Cope 1882 K-JH01
                    |    `--C. joyneri K-JH01
                    `--Taeniolabis Cope 1882 K-JH01
                         |--T. lamberti D07
                         |--T. sulcatus D07
                         `--T. taoensis K-JH97

*Type species of generic name indicated

REFERENCES

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

[K-JH97] Kielan-Jaworowska, Z., & J. H. Hurum. 1997. Djadochtatheria - a new suborder of multituberculate mammals. Acta Palaeontologica Polonica 42 (2): 201–242.

[K-JH01] Kielan-Jaworowska, Z., & J. H. Hurum. 2001. Phylogeny and systematics of multituberculate mammals. Palaeontology 44 (3): 389–429.

Eutriconodonta

Reconstruction of Repenomamus giganticus, copyright Nobu Tamura.

Belongs within: Mammalia.

The Eutriconodonta are a group of mammals known from the Jurassic and Cretaceous, characterised by triconodont molars with three laterally compressed cusps in a straight alignment (Luo et al. 2007).

Synapomorphies (from Krause et al. 2014): Dens not fused to axis; lumbar ribs not fused to vertebrae; tarsal spur absent; premaxilla with ventral internarial process present but not connected to nasal; single infraorbital foramen present; ventral opening of minor palatine foramen encircled by palatine and maxilla; postpalatine torus present; internal acoustic meatus cribriform plate absent; ear region with lateral flange narrowly separated from anterior paroccipital process (crista parotica); pterygoparoccipital foramen a laterally open notch; mallear manubrium robust; suture separating basioccipital and exoccipital absent; two lower and upper incisors in each quadrant; I3 with single cusp; seven lower postcanine teeth in each quadrant; four lower premolars in each quadrant; ultimate upper premolar (P5) with metacone present; penultimate lower premolar (p4) with paraconid (cusp b) absent or indistinct; ultimate lower premolar tooth (p5) with hypoconid absent; m1–2 with paracristid longitudinally oriented relative to longitudinal axis of molars; m1–2 with buccal curvature of protoconid (cusp a) at base level equivalent to curvature of paraconid (cusp b) and metaconid (cusp c); m1–2 with metacristid (protocristid), crest between protoconid (cusp a) and metaconid (cusp c) parallel to long axis of lower molars and lower jaw axis; m1 with main cusps of trigonid in single longitudinal row; m1–2 with labiolingual compression of primary functional cusps (at level of cusp base but above cingulid); M1–2 with stylar shelf absent; M1–2 with lingual cingulum discontinuous; dentary movement during power stroke of chewing cycle essentially dorsal (orthal); molar with prevallum/postvallid shearing absent.

<==Eutriconodonta
    |  i. s.: Phascolotherium Owen 1838 CM99
    |         ‘Kotatherium’ yadagirii Prasad & Manhas 1997 A02
    |--+--Amphilestes [Amphilestinae] KH14
    |  `--Gobiconodontidae LK-JC02
    |       |--Gobiconodon Trofimov 1978 KH14, CM99
    |       |    `--G. zofiae HM05
    |       `--Repenomamus Li, Wang et al. 2000 LC07, HM05 [Repenomamidae]
    |            |--R. giganticus Hu, Meng et al. 2005 HM05
    |            `--R. robustus HM05
    `--+--+--Jeholodens jenkinsi KH14, LC07
       |  `--Yanoconodon Luo, Chen et al. 2007 LC07
       |       `--*Y. allini Luo, Chen et al. 2007 LC07
       `--Triconodontidae [Triconodontinae] LK-JC02
            |--Priacodon KH14
            |--Trioracodon LK-JC02
            `--Astroconodon LK-JC02

*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.

[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.

[HM05] Hu, Y., J. Meng, Y. Wang & C. Li. 2005. Large Mesozoic mammals fed on young dinosaurs. Nature 433: 149–152.

[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.

[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.

[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.

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.

Trechnotheria

Left upper molars of Tinodon (left one) and Symmetrodontoides canadensis (right two) from Palaeos.

Belongs within: Mammalia.
Contains: Cladotheria.

The Trechnotheria are a clade of mammals defined as the most exclusive clade including Zhangheotherium and crown Theria, with the earliest members known from the late Jurassic. Trechnotherians are characterised by the development of a strong postvallum/prevallid shear between the upper and lower molars (Luo et al. 2002). Basal members of the clade, the Spalacotheroidea and Tinodontidae, have been classified in the past as members of the 'symmetrodonts' but this group of early mammals with triangular molars and reduced talonids is now generally regarded as non-monophyletic.

Synapomorphies (from Luo et al. 2002): Hypertrophied postvallum/prevallid shearing mechanism present, with acute triangulation of molar cusps; petrosal with large post-tympanic recess and caudal tympanic process; epitympanic recess bounded by lateral wall formed by squamosal. Scapula with posterior part of supraspinous fossa relatively expanded, far wider than glenoid region, fossa fan-shaped or triangular in outline; supraspinous fossa wider than infraspinous fossa. Proximo-lateral process of tibia vestigial or absent. Humerus with posterior aspect of distal articulation for radius cylindrical. Calcaneus with sustentacular facet oblique to the horizontal plane (uncertain in Spalacotherioidea).

<==Trechnotheria
    |--Spalacotheroidea [Spalacotheriinae] A02
    |    |  i. s.: Heishanlestes MH06
    |    |--Zhangheotherium Hu et al. 1997 KH14, CM99
    |    |    `--Z. quinquecuspidens Hu et al. 1997 A02
    |    `--+--Akidolestes KH14
    |       `--+--Maotherium KH14
    |          `--Spalacotheriidae A02
    |               |  i. s.: Shalbaatar Nessov 1997 A02
    |               |           `--S. bakht Nessov 1997 A02
    |               |--Spalacotherium Owen 1854 KH14, CM99 [incl. Peralestes Owen 1871 A02]
    |               |    `--S. tricuspedens OB13
    |               `--Spalacolestinae CM99
    |                    |--Spalacotheroides Patterson 1955 CM99
    |                    |    `--S. bridwelli Patterson 1955 CM99
    |                    `--+--Spalacotheridium Cifelli 1990 CM99
    |                       |    |--*S. mckennai Cifelli 1990 CM99
    |                       |    `--S. noblei Cifelli & Madsen 1999 CM99
    |                       `--+--Spalacolestes Cifelli & Madsen 1999 CM99
    |                          |    |--*S. cretulablatta Cifelli & Madsen 1999 CM99
    |                          |    `--S. inconcinnus Cifelli & Madsen 1999 CM99
    |                          `--Symmetrodontoides Fox 1976 CM99 [incl. Mictodon Fox 1984 A02]
    |                               |--*S. canadensis Fox 1976 CM99
    |                               |--S. foxi Cifelli & Madsen 1986 CM99
    |                               |--S. oligodontos Cifelli 1990 CM99
    |                               `--‘Mictodon’ symmetrodontoides Fox 1984 A02
    `--+--Tinodontidae A02
       |    |--Gobiotheriodon Trofimov 1997 A02
       |    |    `--G. infinitus (Trofimov 1980) [=Gobiodon infinitus, Gobiondon (l. c.) infinitus] A02
       |    `--Tinodon Marsh 1879 KH14, A02 [incl. Eurylambda Simpson 1929 A02, Menacodon Marsh 1887 A02]
       |         |--T. bellus Marsh 1879 [incl. T. lepidus Marsh 1879] A02
       |         `--T. micron Ensom & Sigogneau-Russell 2000 A02
       `--Cladotheria LK-JC02

*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.

[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.

[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.

[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.

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

[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.

Last updated: 22 August 2018.

Mammalia

Left dentary of Shuotherium dongi in lingual view, from Kielan-Jaworowska et al. (2002).

Belongs within: Mammaliaformes.
Contains: Prototheria, Eutriconodonta, Multituberculata, Trechnotheria.

The name 'Mammalia' has generally been restricted in recent years to the crown-group of mammals, i. e. the smallest possible clade including monotremes, marsupials and placentals. Mammals are distinguished from other living vertebrates by their covering of hair and the production of milk, but these features probably evolved some time before the appearance of the crown group (exactly when being uncertain). Among living mammals, modern authors universally agree on a basal division between monotremes and the remaining taxa (therians). The name Prototheria has been applied to the monotreme total group (all species closer to Ornithorhynchus anatinus than Elephas maximus; O'Leary et al. 2013). Analyses disagree whether the Jurassic Shuotheriidae belong to this clade. The Shuotheriidae possessed a crushing heel, the pseudotalonid, on their molars that differed from the talonid of modern therians in being anterior rather than posterior to the trigonid (Kielan-Jaworowska et al. 2006).

Early members of the lineage leading to modern therians include Fruitafossor windsheffeli, a late Jurassic species from Colorado that is the earliest known mammal specialised for a fossorial (digging) lifestyle. Volaticotherium antiquum of the Chinese Daohugou formation (between middle Jurassic and early Cretaceous in age) bore a large patagium and represents the earliest known gliding mammal (Meng et al. 2006). The Tinodontidae are a Late Jurassic to Early Cretaceous group with lower jaws bearing three premolars and four molars with reduced talonids, and a relatively small and triangular pterygoid fossa (Averianov 2002).

Synapomorphies (from Luo et al. 2002): Occlusal surfaces matching precisely between upper and lower molars upon eruption. Distinctive masseteric fossa present on mandible with a well−defined ventral margin, occupying entire mandibular angle region. Cochlear canal more elongate than in outgroups (although not always coiled). Ossified pila antotica absent between cavum epiptericum and braincase (except in multituberculates). Astragalus and calcaneus usually in partial superposition. Gyrencephalic cerebral hemispheres greatly enlarged (with external gyri and sulci on surface of endocast), at least in living taxa.

<==Mammalia [Holotheria, Marsupionta, Symmetrodonta, Tribosphenida]
    |--+--Prototheria OB13
    |  `--Shuotheriidae [Shuotheridia, Yinotheria] LJY07
    |       |--Pseudotribos Luo, Ji & Yuan 2007 LJY07
    |       |    `--*P. robustus Luo, Ji & Yuan 2007 LJY07
    |       `--Shuotherium Chow & Rich 1982 SK20, K-JCL02
    |            |--*S. dongi Chow & Rich 1982 K-JCL02
    |            |--S. kermacki Sigogneau-Russell 1998 K-JCL02
    |            `--S. shilongi Wang et al. 1998 K-JCL02
    `--Theriimorpha OB13
         |--Fruitafossor Luo & Wible 2005 BW14, D07
         |    `--*F. windsheffeli Luo & Wible 2005 LW05
         |--Volaticotherium Meng, Hu et al. 2006 [Volaticotheria, Volaticotheriidae] MH06
         |    `--*V. antiquum Meng, Hu et al. 2006 MH06, MH07, MH06 [=V. antiquus MH06]
         `--+--Eutriconodonta BW14
            `--Theriiformes LK-JC02
                 |--Multituberculata BW14
                 |--Trechnotheria BW14
                 `--Tinodontidae A02
                      |--Gobiotheriodon Trofimov 1997 A02
                      |    `--G. infinitus (Trofimov 1980) [=Gobiodon infinitus, Gobiondon (l. c.) infinitus] A02
                      `--Tinodon Marsh 1879 SK20, A02 [incl. Eurylambda Simpson 1929 A02, Menacodon Marsh 1887 A02]
                           |--T. bellus Marsh 1879 [incl. T. lepidus Marsh 1879] A02
                           `--T. micron Ensom & Sigogneau-Russell 2000 A02

Mammalia incertae sedis:
  Hypomylos LCK-J01
    |--H. micros H98
    `--H. phelizioni H98
  Hohomys lii Hu 1995 MHL03
  Motheretus telhebresus MHL03
  Untermannerix copiosus MHL03
  Dzungariotherium orgosense DW04
  Alloptox minor DW04
  Megacricetodon M-SA09
    |--M. ibericus M-SA09
    |--M. minor M-SK04
    |    |--M. m. minor M-SK04
    |    `--M. m. debruijni M-SK04
    `--M. sinensis DW04
  Sayimys obliquidens DW04
  Hispanotherium DW04
    |--H. matritense DW04
    `--H. tungurense DW04
  Dinocrocuta gigantea DW04
  Acerorhinus DW04
    |--A. fuguensis DW04
    |--A. hezhengensis DW04
    |--A. palaeosinensis DW04
    `--A. tsaidamensis DW04
  Pararhizomys hipparionum DW04
  Iranotherium morgani DW04
  Honanotherium schlosseri DW04
  Parataxidea sinensis DW04
  Eotheomys imaizumii (Jameson 1961) I92
  Acanthonotus Goldfuss 1809 C92
  Paraglirulus werenfelsi M-SK04
  Glirudinus undosus M-SK04
  Albanensia albanensis M-SK04
  Tapiravus polkensis WW04
  Wanotherium xuanchengensis HC97
  Pseudostoma Say 1823 [=Pseudotoma (l. c.) non Bellardi 1875] BR05
  Spinigera Lesson 1842 BR05
  Nothodectes gidleyi Matthew 1917 S35a
  Megopterna minuta Douglass 1908 S35b
  Cuscus G66
    |--C. brevicaudatus G66
    `--C. maculatus [incl. C. m. var. ochropus] G66
  Liaotherium Zhou et al. 1991 A02
    `--L. gracile Zhou et al. 1991 A02
  Sciuropterus W69
    |--S. horsfieldi T00
    |--S. hosei Thomas 1900 T00
    |--S. platyurus T00
    |--S. setosus T00
    |--S. thomsoni Thomas 1900 T00
    `--S. uphami W69
  Metacervulus astylodon AC98
  ‘Liops’ Gidley 1906 non Fieber 1870 KA-Z11
  Nakunodon Yadagiri 1985 A02
  Dinocyon thenardi V67
  Isodon Say 1822 CW92
  ‘Cynocephalus’ Geoffroy & Cuvier 1795 non Boddaërt 1768 C84
  Rhizoprion Jourdan 1861 C84
  Hapalotis R87
    |--H. apicalis R87
    |--H. boweri Ramsay 1887 R87
    `--H. hemileucura R87
  Sipalus Fischer 1813 Z93
  Thylacodictis Mercerat 1891 (see below for synonymy) V65
  Viscacia viscacia O05
  Platatherium pampaeum O05
  Pseudolestodon miloides O05
  Chlamydotherium typum O05
  Kuehneotheriidae A02
    |--Delsatia Sigogneau-Russell & Godefroit 1997 A02
    |--Kuehneotherium Kermack, Kermack & Mussett 1968 RW12, A02 [incl. Kuehneon Kretzoi 1960 (n. d.) A02]
    |    `--K. praecursoris Kermack, Kermack & Mussett 1968 S05
    `--Kotatherium Datta 1981 A02
         `--K. haldanei Datta 1981 A02
  Tribotherium africanum H98
  Meemannodon lujiatunensis MWL11
  Tapomys tapensis W96
  Shunkahetanka geringensis TS96
  Hitonkala andersontau TS96
  Alwoodia harkseni TS96
  Xenostephanus Simpson, Minoprio & Paterson 1962 EH19

Thylacodictis Mercerat 1891 [incl. Amphiproviverra Ameghino 1891, Protoproviverra Ameghino 1891 non Lemoine 1891] V65

*Type species of generic name indicated

REFERENCES

[AC98] Alcover, J. A., X. Campillo, M. Macias & A. Sans. 1998. Mammal species of the world: additional data on insular mammals. American Museum Novitates 3248: 1–29.

[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.

[BR05] Bouchet, P., & J.-P. Rocroi. 2005. Classification and nomenclator of gastropod families. Malacologia 47 (1–2): 1–397.

[CW92] Cassis, G., & T. A. Weir. 1992. Dynastinae. In: Houston, W. W. K. (ed.) Zoological Catalogue of Australia vol. 9. Coleoptera: Scarabaeoidea pp. 383–425. AGPS Press: Canberra.

[C84] Compagno, L. J. V. 1984. FAO Species Catalogue vol. 4. Sharks of the World: An annotated and illustrated catalogue of shark species known to date. Part 2—Carcharhiniformes. United Nations Development Programme, Food and Agriculture Organization of the United Nations: Rome.

[C92] Crawford, R. L. 1992. Catalogue of the genera and type species of the harvestman superfamily Phalangioidea (Arachnida). Burke Museum Contributions in Anthropology and Natural History 8: 1–60.

[DW04] Deng T., Wang X., Ni X. & Liu L. 2004. Sequence of the Cenozoic mammalian faunas of the Linxia Basin in Gansu, China. Acta Geologica Sinica (English Edition) 78 (1): 8–14.

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

[EH19] Énay, R., & M. K. Howarth. 2019. Part L, revised, volume 3B, chapter 7: Systematic descriptions of the Perisphinctoidea. Treatise Online 120: 1–184.

[G66] Gray, J. E. 1866. Notes on some Mammalia from Port Albany (Cape York Peninsula), North Australia, with the descriptions of some new species. Proceedings of the Zoological Society of London 1866: 219–221.

[H98] Heinrich, W.-D. 1998. Late Jurassic mammals from Tendaguru, Tanzania, east Africa. Journal of Mammalian Evolution 5 (4): 269–290.

[HC97] Huang X. & Chen L. 1997. Mammalian remains from the Late Paleocene of Guichi, Anhui. Vertebrata PalAsiatica 35 (1): 49–67.

[I92] Iwahashi, J. (ed.) 1992. Reddo Deeta Animaruzu: a pictorial of Japanese fauna facing extinction. JICC: Tokyo.

[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.

[KA-Z11] Kury, A. B., & M. A. Alonso-Zarazaga. 2011. Addenda and corrigenda to the “Annotated catalogue of the Laniatores of the New World (Arachnida, Opiliones)”. Zootaxa 3034: 47–68.

[LCK-J01] Luo, Z.-X., R. L. Cifelli & Z. Kielan-Jaworowska. 2001. Dual origin of tribosphenic mammals. Nature 409: 53–57.

[LJY07] Luo, Z.-X., Q. Ji & C.-X. Yuan. 2007. Convergent dental adaptations in pseudo-tribosphenic and tribosphenic mammals. Nature 450: 93–97.

[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.

[LW05] Luo, Z.-X., & J. R. Wible. 2005. A Late Jurassic digging mammal and early mammalian diversification. Science 308: 103–107.

[MHL03] Meng, J., Y. Hu & C. Li. 2003. The osteology of Rhombomylus (Mammalia, Glires): implications for phylogeny and evolution of Glires. Bulletin of the American Museum of Natural History 275: 1–247.

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

[MH07] Meng, J., Y. Hu, Y. Wang, X. Wang & C. Li. 2007. Corrigendum: A Mesozoic gliding mammal from northeastern China. Nature 446: 102.

[MWL11] Meng, J., Y. Wang & C. Li. 2011. Transitional mammalian middle ear from a new Cretaceous Jehol eutriconodont. Nature 472: 181–185.

[M-SA09] Moyà-Solà, S., D. M. Alba, S. Almécija, I. Casanovas-Vilar, M. Köhler, S. De Esteban-Trivigno, J. M. Robles, J. Galindo & J. Fortuny. 2009. A unique Middle Miocene European hominoid and the origins of the great ape and human clade. Proceedings of the National Academy of Sciences of the USA 106 (24): 9601–9606.

[M-SK04] Moyà-Solà, S., M. Köhler, D. M. Alba, I. Casanovas-Vilar & J. Galindo. 2004. Pierolapithecus catalaunicus, a new Middle Miocene great ape from Spain. Science 306: 1339–1344.

[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.

[O05] Outes, F. F. 1905. Sobre un instrumento paleolítico de Luján (Provincia de Buenos Aires). Anales del Museo Nacional de Buenos Aires, serie 3, 6: 169–173.

[R87] Ramsay, E. P. 1887. Description of a new species of Hapalotis, (H. boweri) from north west Australia. Proceedings of the Linnean Society of New South Wales, series 2, 1 (4): 1153–1154, pl. 18.

[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.

[S35a] Simpson, G. G. 1935a. The Tiffany fauna, Upper Paleocene. I.–Multituberculata, Marsupialia, Insectivora, and ?Chiroptera. American Museum Novitates 795: 1–19.

[S35b] Simpson, G. G. 1935b. New Paleocene mammals from the Fort Union of Montana. Proceedings of the United States National Museum 83 (2981): 221–244.

[SK20] Sulej, T., G. Krzesiński, M. Tałanda, A. S. Wolniewicz, B. Błażejowski, N. Bonde, P. Gutowski, M. Sienkiewicz & G. Niedźwiedzki. 2020. The earliest-known mammaliaform fossil from Greenland sheds light on origin of mammals. Proceedings of the National Academy of Sciences of the USA 117 (43): 26861–26867.

[TS96] Tedford, R. H., J. B. Swinehart, C. C. Swisher III, D. R. Prothero, S. A. King & T. E. Tierney. 1996. The Whitneyan-Arikareean transition in the High Plains. In: Prothero, D. R., & R. J. Emry (eds) The Terrestrial Eocene–Oligocene Transition in North America pp. 312–334. Cambridge University Press.

[T00] Thomas, O. 1900. Descriptions of two new Sciuropteri discovered by Mr. Charles Hose in Borneo. Annals and Magazine of Natural History, series 7, 5: 275–276.

[V65] Van Valen, L. 1965. Some European Proviverrini (Mammalia, Deltatheridia). Palaeontology 8 (4): 638–665.

[V67] Van Valen, L. 1967. New Paleocene insectivores and insectivore classification. Bulletin of the American Museum of Natural History 135 (5): 217–284.

[WW04] Wallace, S. C., & X. Wang. 2004. Two new carnivores from an unusual late Tertiary forest biota in eastern North America. Nature 431: 556–559.

[W96] Walsh, S. L. 1996. S. Middle Eocene mammal faunas of San Diego County, California. In: Prothero, D. R., & R. J. Emry (eds) The Terrestrial Eocene–Oligocene Transition in North America pp. 75–119. Cambridge University Press.

[W69] Woodburne, M. O. 1969. Systematics, biogeography, and evolution of Cynorca and Dyseohyus (Tayassuidae). Bulletin of the American Museum of Natural History 141 (2): 271–356.

[Z93] Zimmerman, E. C. 1993. Australian Weevils (Coleoptera: Curculionoidea) vol. 3. Nanophyidae, Rhynchophoridae, Erirhinidae, Curculionidae: Amycterinae, literature consulted. CSIRO Australia.

Last updated: 19 March 2022.

Boreosphenida

Right upper molar of Kielantherium gobiensis in (a) occlusal, (b) anterior and (c) labial views, from Lopatin & Averianov (2006).

Belongs within: Trechnotheria.
Contains: Metatheria, Eutheria.

The Boreosphenida is the clade uniting modern marsupials and placentals with their immediate fossil relatives sharing ancestrally tribosphenic molars (with three cusps).

Synapomorphies (from Rougier et al. 1998): Protocone small with distinct trigon basin (inferred from talonid); lower molar talonid with multicuspidated basin.

<==Boreosphenida
    |  i. s.: Tribactonodon VG09
    |         Kermackia FP99
    |--Kielantherium gobiensis LC07, WR07
    `--+--Aegialodon LC07
       |--Potamolestes RWN98
       `--+--Slaughteria RWN98
          `--+--Pappotherium FP99
             `--Theria [Creophaga, Deltatheridia, Deltatheridioidea, Insectivora, Palaeoryctoidea, Sarcobora] WR07
                  |  i. s.: Chronozoon DeVis 1883 LA02
                  |           `--*C. australe DeVis 1883 LA02
                  |         Mixodectidae S35
                  |           |--Mixodectes S35
                  |           `--Eudaemonema Simpson 1935 S35
                  |                `--*E. cuspidata Simpson 1935 S35
                  |         Vulpavoides Matthes 1952 V66
                  |         Ziphacodon Marsh 1872 (n. d.) V66
                  |         Aethechinus algirus JP84
                  |         Miothen Cope 1873 M60
                  |           |--*M. crassigenus Cope 1873 M60
                  |           `--M. gracile Cope 1873 M60
                  |--Metatheria WR07
                  `--Eutheria WR07

*Type species of generic name indicated

REFERENCES

[FP99] Flynn, J. J., J. M. Parrish, B. Rakotosamimanana, W. F. Simpson & A. R. Wyss. 1999. A Middle Jurassic mammal from Madagascar. Nature 401: 57-60.

[JP84] Jolicoeur, P., P. Pirlot, G. Baron & H. Stephan. 1984. Brain structure and correlation patterns in Insectivora, Chiroptera, and Primates. Systematic Zoology 33 (1): 14-29.

[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.

Lopatin, A. V., & A. O. Averianov. 2006. An aegialodontid upper molar and the evolution of mammal dentition. Science 313: 1092.

[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.

[M60] McKenna, M. C. 1960. The Geolabidinae: a new subfamily of early Cenozoic erinaceoid insectivores. University of California Publications in Geological Sciences 37 (2): 131-164.

[RWN98] Rougier, G. W., J. R. Wible & M. J. Novacek. 1998. Implications of Deltatheridium specimens for early marsupial history. Nature 396: 459-463.

[S35] Simpson, G. G. 1935. New Paleocene mammals from the Fort Union of Montana. Proceedings of the United States National Museum 83 (2981): 221-244.

[V66] Van Valen, L. 1966. Deltatheridia, a new order of mammals. Bulletin of the American Museum of Natural History 132 (1): 1-126.

[VG09] Vullo, R., E. Gheerbrant, C. De Muizon & D. Néraudeau. 2009. The oldest modern therian mammal from Europe and its bearing on stem marsupial paleobiogeography. Proceedings of the National Academy of Sciences of the USA 106 (47): 19910-19915.

[WR07] Wible, J. R., G. W. Rougier, M. J. Novacek & R. J. Asher. 2007. Cretaceous eutherians and Laurasian origin for placental mammals near the K/T boundary. Nature 447: 1003-1006.

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.