Holotheria

Holotheria is a diverse group of mammals that are descendants of the last common ancestor of Kuehneotherium (now known to be a non-mammalian cynodont) and Theria (the group that includes marsupials and placental mammals).^[2] The group is characterized by the beginning of the triangulation of a typical triconodont dentition in morganucodonts, towards a symmetrodonta. This triangulation occurs convergently in Docodontiformes^[3] although Shuotheriidae was formerly considered sister to Australosphenida.^[4] There are studies that place Docodonta as sister to Monotremata,^[5] which would make Docodontiformes fall within Pan-Monotremata instead of being a clade outside Holotheria.^[3]

Holotheria fell into disuse and was widely considered invalid by the early 2000s, but Mao et al. in 2024 revived the clade due to them finding Allotheria (the group containing multituberculates and their relatives) outside crown group of mammals.^[3]

Classification

According to McKenna/Bell (1997):^[1]

• Class Mammalia
  • Subclass Theriiformes
    • Infraclass Holotheria
      • Genus Chronoperates?
      • Superlegion Kuehneotheria
        • Genus Woutersia
        • Family Kuehneotheriidae
      • Superlegion Trechnotheria
        • Legion Symmetrodonta*
          • Genus Casamiquelia?
          • Genus Thereuodon?
          • Genus Atlasodon?
          • Genus Eurylambda?
          • Genus Peralestes?
          • Genus Shuotherium?
          • Order Amphidontoidea
            • Family Amphidontidae
          • Order Spalacotherioidea
            • Genus Gobiotheriodon?
            • Genus Maotherium
            • Genus Zhangheotherium
            • Family Tinodontidae
            • Family Barbereniidae?
              • Genus Guirogatherium?
              • Genus Barberenia?
            • Family Spalacotheriidae
              • Genus Microderson
              • Genus Shalbaatar
              • Genus Spalacotherium
              • Subfamily Spalacolestinae
                • Genus Symmetrolestes
                • Genus Akidolestes
                • Genus Heishanlestes
                • Genus Spalacotheroides
                • Genus Spalacotheridium
                • Genus Spalacolestes
                • Genus Symmetrodontoides
        • Legion Cladotheria
          • Genus Butlerigale?
          • Family Ausktribosphenidae?
          • Sublegion Dryolestoidea
            • Order Dryolestida
            • Order Amphitheriida
          • Sublegion Zatheria
            • Infralegion Peramura
            • Infralegion Tribosphenida
              • Genus Ambondro?
              • Genus Hypomylos?
              • Genus Montanalestes?
              • Genus Tribactonodon?
              • Supercohort Aegialodontia
                • Family Aegialodontidae
                  • Genus Aegialodon
                  • Genus Kielantherium
              • Supercohort Theria
                • Order Deltatheroida
                • Order Asiadelphia
                • Cohort Marsupialia
                  • Magnorder Australidelphia
                  • Superorder Microbiotheria
                  • Superorder Eometatheria
                    • • Order Yalkaparidontia
                      • Order Notoryctemorphia
                    • Grandorder Dasyuromorphia
                    • Grandorder Syndactyli
                      • Order Peramelia
                      • Order Diprotodontia
                  • Magnorder Ameridelphia
                • Cohort Placentalia
                  • • • Order Bibymalagasia
                  • Magnorder Xenarthra
                  • Magnorder Epitheria

According to Wang, Clemens, Hu & Li, 1998^[6]

• Class Mammalia
  • Subclass Theriiformes
    • Infraclass Holotheria
      • Genus Chronoperates?
      • Superlegion Kuehneotheria
      • Superlegion Trechnotheria
        • Family Amphidontidae
        • Superfamily Spalacotheroidea
        • Legion Symmetrodonta
          • Genus Asfaltomylos?
          • Genus Atlasodon?
          • Family Ausktribosphenidae?
          • Genus Casamiquelia?
          • Genus Thereuodon?
          • Genus Eurylambda?
          • Genus Shuotherium
        • Legion Cladotheria
          • Genus Butlerigale?
          • Sublegion Dryolestoidea
            • Order Dryolestida
            • Order Amphitheriida
            • Genus Amphitherium
          • Sublegion Zatheria
            • Genus Arguitherium?
            • Genus Arguimus?
            • Genus Nanolestes?
            • Genus Vincelestes?
            • Infralegion Peramura
            • Infralegion Tribosphenida

References

1. ^ Mckenna. "Holotheria". Mikko's Phylogenetical Archive. Retrieved 19 July 2013.
2. ^ Wible, J. R., Rougier, G. W., Novacek, M. J. & McKenna, M. C. (2001). "Earliest eutherian ear region: A petrosal referred to Prokennalestes from the Early Cretaceous of Mongolia." American Museum Novitates, 3322.
3. ^ Mao, Fangyuan; Li, Zhiyu; Wang, Zhili; Zhang, Chi; Rich, Thomas; Vickers-Rich, Patricia; Meng, Jin (April 2024). "Jurassic shuotheriids show earliest dental diversification of mammaliaforms". Nature. 628 (8008): 569–575. Bibcode:2024Natur.628..569M. doi:10.1038/s41586-024-07258-7. ISSN 1476-4687. PMID 38570681
4. ^ Luo, Zhe-Xi; Ji, Qiang; Yuan, Chong-Xi (November 2007). "Convergent dental adaptations in pseudo-tribosphenic and tribosphenic mammals". Nature. 450 (7166): 93–97. Bibcode:2007Natur.450...93L. doi:10.1038/nature06221. ISSN 1476-4687. PMID 17972884
5. ^ Hoffmann, Simone; Beck, Robin M. D.; Wible, John R.; Rougier, Guillermo W.; Krause, David W. (2020-12-14). "Phylogenetic placement of Adalatherium hui (Mammalia, Gondwanatheria) from the Late Cretaceous of Madagascar: implications for allotherian relationships". Journal of Vertebrate Paleontology. 40 (sup1): 213–234. Bibcode:2020JVPal..40S.213H. doi:10.1080/02724634.2020.1801706. ISSN 0272-4634
6. ^ Wang; Clemens; Hu; & Li. "Holotheria". Mikko's Phylogenetical Archive. Retrieved 19 July 2013.