{{Short description|Extinct genus of dinosaurs}} {{Automatic taxobox | image = Aublysodon.jpg | image_caption = Illustrations of the teeth by Leidy and O. C. Marsh, 4: ''A. mirandus'' 5: "A." ''amplus'' 6: "A." ''cristatus'' | fossil_range = {{fossil range|75|prefix=Late Campanian, }}{{period fossil range|Cretaceous|75}} | display_parents = 3 | parent_authority = Nopcsa, 1928 <br>''nomen dubium'' | taxon = Aublysodon | authority = Leidy, 1868 <br>''nomen dubium'' | type_species = {{extinct}}'''''Aublysodon mirandus''''' | type_species_authority = Leidy, 1868 | subdivision_ranks = Species | subdivision = *{{extinct}}'''''A. mirandus''''' <small>Leidy, 1868 ''nomen dubium''</small> *{{extinct}}'''''A. cristatus'''''? <small>Marsh, 1892 ''nomen dubium''</small> and see text | synonyms = *''Ornithomimus mirandus'' <small>(Leidy, 1868) Hay, 1930</small> }}
'''''Aublysodon''''' (“backwards-flowing tooth") is a dubious genus of carnivorous dinosaurs known only from the Judith River Formation in Montana, which has been dated to the late Campanian age of the late Cretaceous period (about 75 million years ago).
The only currently recognized species, '''''Aublysodon mirandus''''', was named by paleontologist Joseph Leidy in 1868. It is sometimes considered dubious now because the type specimen consists only of an isolated premaxillary (front) tooth. Although this specimen is now lost, similar teeth have been found in many US states, western Canada, and Asia.<ref name="ageofdinosaursaublysodon"/> These teeth almost certainly belong to juvenile tyrannosaurine tyrannosaurids, but most have not been identified to species level. However, it is likely that the type tooth (and therefore the name ''A. mirandus'' itself) belongs to one of the species in the genus ''Daspletosaurus'', which was present in contemporary formations, and which matches specific details of the original tooth.<ref name=currie2005/>
The synapomorphies alleged to distinguish the Aublysodontinae, especially lack of serrations on premaxillary teeth, could have been caused by tooth wear in life, postmortem abrasion, or digestion.<ref name="tyrant-tax-res-67" /> Most other "aublysodontine"-type teeth may be from ontogenetic stages or sexual morphs of other tyrannosaurids.<ref name="tyrant-tax-res-67" /> Apart from the type species ''A. mirandus,'' several other species have been named over the years. These are now all considered either dubious, identical to other species, or even as having no close connection to ''A. mirandus''.
==History== In the mid-to-late 19th century many dinosaur taxa were named for isolated teeth; such genera include ''Trachodon'', ''Palaeoscincus'', and ''Troodon''. Even before the badlands of North America started revealing the bones of ''Tyrannosaurus'', teeth turning up in many localities in the Western United States revealed the presence of large predatory dinosaurs.
In 1856 Joseph Leidy had named fourteen teeth collected by Ferdinand Vandeveer Hayden in 1854 and 1855 from the Judith River Badlands of Montana<ref name="ageofdinosaursaublysodon"/> as the species ''Deinodon horridus''.<ref>Leidy, J., 1856, "Notices of the remains of extinct reptiles and fishes, discovered by Dr. F.V. Hayden in the badlands of the Judith River, Nebraska Territory", ''Proceedings of the Academy of Natural Sciences'' '''8'''(2): 72</ref> In 1866 Edward Drinker Cope chose three nonserrated teeth from the original syntype series of fourteen as the lectotypes of ''Deinodon horridus''.<ref>Cope, E.D., 1866, "Discovery of a gigantic dinosaur in the Cretaceous of New Jersey", ''Proceedings of the Academy of Natural Sciences of Philadelphia'', '''18''': 275-279</ref> Leidy named these same three teeth ''Aublysodon mirandus'' in 1868. The meaning of the generic name is uncertain because Leidy himself gave no etymology or explanation of the intended meaning. It is possible the genus name is derived from Greek αὖ, ''au'', "again", "backwards", "contrariwise", βλύζω, ''blyzo'', "to spout", "to flow" and ὀδών, ''odon'', "tooth". The specific name means "wonderful" or "strange" in Latin.{{citation needed|date=November 2022}} [[File:Deinodon.JPG|left|thumb|300px|Lithography of the original syntypes of ''Deinodon'': the small tooth shown in figures 41-45 is ANSP 9535, the later lectotype of ''Aublysodon mirandus''. Figures 37-40 show ANSP 9533, and figures 33 and 34 specimen ANSP 9534, the later lectotypes of ''Deinodon horridus'']] Because the name ''Aublysodon mirandus'' was based on the same type, it was at first a junior objective synonym of ''Deinodon horridus'', which latter name thus had priority. Cope in 1868 mistakenly thought the name ''Deinodon'' was preoccupied by the snake ''Dinodon'' and renamed ''Deinodon horridus'' into an ''Aublysodon horridus''.<ref>Cope, E.D., 1868, "On some Cretaceous Reptilia", ''Proceedings of the Academy of Natural Sciences of Philadelphia'', '''20''': 233-242</ref> If ''Deinodon'' really had been preoccupied, this would have made ''Aublysodon'' a valid genus. In 1899 Oliver Perry Hay pointed out Cope's mistake; ''Aublysodon horridus'' is a junior objective synonym of ''Deinodon horridus'', just as ''Aublysodon mirandus'' had been.<ref>Hay, O.P., 1899, "On the nomenclature of certain American fossil vertebrates", ''American Geologist'' '''24''': 345-349</ref> However, in 1892 ''Aublysodon'' became an independent genus when Othniel Charles Marsh further limited its type by choosing a single small nonserrated premaxillary tooth with a D-shaped cross-section, specimen ANSP 9535, as the lectotype of ''Aublysodon mirandus''.<ref name=Marsh1892>Marsh, O.C., 1892, "Notes on Mesozoic vertebrate fossils", ''American Journal of Science'', '''44''': 170-176</ref> The two other teeth, ANSP 9533 and ANSP 9534, remained as the lectotypes of ''Deinodon horridus''. The names were thus separated.<ref>Carpenter, K., 1982, "Baby dinosaurs from the Late Cretaceous Lance and Hell Creek formations and a description of a new species of theropod", ''Contributions to Geology, University of Wyoming'', '''20'''(2): 123-134</ref>
The tooth-based taxon ''Aublysodon'' was a mystery for a long time since no further skeletal elements were found that could be assigned with certainty to the teeth. In the early twentieth century it was assumed by some workers that it represented a member of the Ornithomimidae when it was not yet known this group was toothless. Lawrence Morris Lambe in 1902 referred the tooth to ''Struthiomimus'';<ref>*Lambe, L.M., 1902, "New genera and species from the Belly River Series (mid-Cretaceous)", ''Geological Survey of Canada Contributions to Canadian Palaeontology'' '''3'''(2): 25-81</ref> Hay in 1930 renamed ''A. mirandus'' into ''Ornithomimus mirandus'',<ref>Hay, O.P., 1930, ''Second Bibliography and Catalogue of the Fossil Vertebrata of North America''. Carnegie Institution of Washington. '''390'''(II), pp 1-1074</ref> forgetting in that case ''Aublysodon'' would have priority.
Today it is known that similar teeth are found in juvenile specimens of ''Daspletosaurus'', and it is likely that teeth referred to ''Aublysodon'' came from that genus.<ref name=currie2005>Currie, P. (2005). "Theropods, including birds." Pp. 367-397 in Currie and Koppelhus (eds)., ''Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed''. Bloomington: Indiana University Press.</ref> In October 2000, the type specimen of ''Aublysodon'' went missing when being sent by registered mail from the Academy of Natural Sciences of Philadelphia to the Field Museum of Natural History. Because of the presence of ''Aublysodon''-type teeth in other juvenile tyrannosaurines than ''Daspletosaurus'', such as those of ''Tyrannosaurus'', remains of which can also be found in Montana, Thomas Carr no longer considered the name to represent a real biological taxon, but to be a ''nomen dubium''.<ref name=CW04/>
===Referred species=== Apart from ''Aublysodon mirandus'' and ''A. horridus'' several other species have been named within the genus. In 1876 Cope created an ''Aublysodon lateralis'', based on specimen AMNH 3956,<ref>Cope, E.D., 1876, "Descriptions of some vertebrate remains from the Fort Union Beds of Montana", ''Paleontological Bulletin'', '''22''': 1-14</ref><ref>Cope, E.D., 1876, "Descriptions of some vertebrate remains from the Fort Union Beds of Montana", ''Proceedings of the Academy of Natural Sciences of Philadelphia'', '''28''': 248-261</ref> a tooth of a juvenile tyrannosaur which has been synonymized with ''Deinodon horridus''.<ref name=sahni1972>Sahni, A. (1972). "The vertebrate fauna of the Judith River Formation, Montana." ''Bulletin of the AMNH'', '''147'''(6).</ref> In 1892 Marsh named two more species: ''Aublysodon amplus'' and ''Aublysodon cristatus'', respectively based on teeth YPM 296 and YPM 297; the latter has also been placed in the genus ''Deinodon''.<ref name=Marsh1892/> They may represent teeth from juvenile individuals of ''T. rex'' as they were found in the Maastrichtian Lance Formation.<ref name=CW04>Carr and Williamson (2004).</ref> In 1903 John Bell Hatcher renamed ''Laelaps explanatus'' Cope 1876 into an ''Aublysodon explanatus''.<ref>Hatcher, J.B., 1903, "Osteology of ''Haplocanthosaurus'', with description of a new species, and remarks on the probable habits of the Sauropoda and the age and origin of the Atlantosaurus Beds", ''Memoirs of the Carnegie Museum'', '''2'''(1): 1-72</ref> This probably represents a tooth of ''Saurornitholestes''. In 1932 Friedrich von Huene classified a fragmentary skeleton named ''Ornithomimus grandis'' by Marsh in 1890 as ''Aublysodon grandis'',<ref>Huene, F. von, 1932, ''Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte''. Monographien zur Geologie und Palaeontologie. '''4'''(1-2), pp 1-361</ref> but most later researchers have considered this a synonym of the Campanian tyrannosaur ''Deinodon horridus''.<ref name="sahni1972"/> In 1967 Alan Jack Charig named three species: ''Aublysodon lancinator'', ''Aublysodon novojilovi'' and ''Aublysodon lancensis''; these had originally been species of ''Gorgosaurus''.<ref>Charig, A.J., 1967, "Archosauria", pp 708-718 in: Walter Brian Harland (ed.) ''The Fossil Record: A Symposium with Documentation, jointly sponsored by the Geological Society of London and the Palaeontological Association'', Geological Society of London, pp 827</ref> The first two are today seen as juvenile specimens of ''Tarbosaurus'';<ref>Rozhdestvensky, A.K., 1965, "Возрастная изменчивость и некоторые вопросы систематики динозавров Азии", ''Палеонтологический журнал'' '''1965'''(3): 95-109</ref> the last represents either a juvenile individual of ''Tyrannosaurus'' or a separate genus ''Nanotyrannus''.<ref>Bakker, R.T., Williams, M. & Currie, P.J., 1988, "''Nanotyrannus'', a new genus of pygmy tyrannosaur, from the latest Cretaceous of Montana", ''Hunteria'' 1(5): 1-30</ref>
The first skeletal material referred to an original ''Aublysodon'' species was a partial skull unearthed in Jordan, Montana<ref name="ageofdinosaursaublysodon">"Aublysodon." Dodson, et al. Page 128.</ref> in 1966 and described by Ralph Molnar in 1977/1978.<ref>Molnar, R.E., 1978, "A new theropod dinosaur from the Upper Cretaceous of central Montana", ''Journal of Paleontology'' '''52'''(1): 73-82</ref> The skull, specimen LACM 28741 at forty-five centimetres the length of an average human arm, bore pointed teeth attached to a long narrow snout. First thought to be a juvenile ''Tyrannosaurus'', then interpreted as a large dromaeosaurid, this "Jordan theropod" was given the name ''Aublysodon molnaris'' by Gregory S. Paul in 1988;<ref name=Paul1988>Paul, G.S., 1988, ''Predatory Dinosaurs of the World''. Simon & Schuster, New York, pp 464</ref> in 1990 the name was by Paul emended to ''Aublysodon molnari'', applying the correct genitive.{{citation needed|date=March 2020}} It was made a separate genus ''Stygivenator'' by George Olshevsky in 1995,<ref>Olshevsky, G.; Ford, T.L. & Yamamoto, S., 1995, "The origin and evolution of the tyrannosaurids", ''Kyoryugaku Saizensen'' '''9/10''': 92-119/75-99</ref> but was later, in 2004, reinterpreted to be a juvenile ''Tyrannosaurus rex'' by Thomas Carr and Tom Williamson.<ref name=CW04/> Another partial skeleton from New Mexico, specimen OMNH 10131, was in 1990 considered to represent ''Aublysodon'',<ref>Lehman, T.M., Carpenter, K., 1990, "A partial skeleton of the tyrannosaurid dinosaur ''Aublysodon'' from the Upper Cretaceous of New Mexico", ''Journal of Paleontology'' '''64''': 1026-1032</ref> but later research by Thomas Carr and Tom Williamson first referred it to ''Daspletosaurus''<ref name=CW04/> and ultimately to ''Bistahieversor''.<ref>Carr, T.D., Williamson, T.E., 2010, "''Bistahieversor sealeyi'', gen. et sp. nov., a new tyrannosauroid from New Mexico and the origin of deep snouts in Tyrannosauroidea", ''Journal of Vertebrate Paleontology'' '''30''' (1): 1-16</ref> In 1988 Paul also created another species when renaming ''Shanshanosaurus huoyanshanensis'' Dong 1977 into ''Aublysodon huoyanshanensis''.<ref name=Paul1988/> It probably represents a ''Tarbosaurus'' specimen.<ref>Currie, P.J., J.H. Hurum, and K. Sabath, 2003, "Skull structure and evolution in tyrannosaurid dinosaurs", ''Acta Palaeontologica Polonica'' 48: 227–234</ref>
==Classification== Cope assigned ''Aublysodon'' to the Goniopoda in 1870,<ref>Cope, E.D., 1870, "Synopsis of the extinct Batrachia, Reptilia and Aves of North America", ''Transactions of the American Philosophical Society'', New Series '''14'''(1): 1-252</ref> a group roughly equivalent to the modern Theropoda. Marsh however, in 1892 was misled by the small size of the teeth, their D-shaped cross-section and their lack of serrations into considering ''Aublysodon'' a mammal exceptionally large for the Cretaceous.<ref name=Marsh1892/> By the early twentieth century it was again generally understood that ''Aublysodon'' was a theropod reptile; later it would be typically assigned to the Deinodontidae, a group today called the Tyrannosauridae.
''Aublysodon'' was by Paul in 1988 thought to belong to a unique subfamily of tyrannosaurids called the Aublysodontinae,<ref name=Paul1988/> a name already coined, together with an Aublysodontidae, by Franz Nopcsa in 1928.<ref>Nopcsa, F., 1928, "The genera of reptiles", ''Palaeobiologica'' '''1''': 163-188</ref> This was a concept which afterwards enjoyed some popularity: Thomas Holtz proposed a stem clade definition of the Aublysodontinae in 2001, "''Aublysodon'' and all taxa sharing a more recent common ancestor with it than with ''Tyrannosaurus''".<ref name="tyrant-tax-res-66" />
''Aublysodon'' was for a time also used in definitions of higher-level taxa. Holtz proposed a node clade definition of the Tyrannosauridae in 2001 as "all descendants of the most recent common ancestor of ''Tyrannosaurus'' and ''Aublysodon''", using ''Aublysodon'' as an anchor taxon.<ref name="tyrant-tax-res-66" /> Paul Sereno has also used ''Aublysodon'' as an anchor taxon for the Tyrannosauridae, although his definition was problematic for other reasons.<ref name="tyrant-tax-res-67" /> These concepts have now been redefined without the dubious name.
Because ''Aublysodon'' is today considered a ''nomen dubium'' based on material probably belonging to ''Daspletosaurus'', its affiliations are likely tyrannosaurid and the terms Aublysodontinae and Aublysodontidae have become irrelevant.
==See also== {{Portal|Dinosaurs}} * Timeline of tyrannosaur research
==Footnotes== {{Reflist|2|refs= <ref name="tyrant-tax-res-66">"Results," in Holtz (2001). Pg. 66.</ref> <ref name="tyrant-tax-res-67">"Results," in Holtz (2001). Pg. 67.</ref> }}
==References== * {{cite journal |last=Carr |first=T.D. |author2=and Williamson, T.E. |year=2004 |title=Diversity of late Maastrichtian Tyrannosauridae (Dinosauria: Theropoda) from western North America |journal=Zoological Journal of the Linnean Society |volume=142 |issue=4 |pages=479–523 |doi=10.1111/j.1096-3642.2004.00130.x|doi-access=free }} * Dodson, Peter & Britt, Brooks & Carpenter, Kenneth & Forster, Catherine A. & Gillette, David D. & Norell, Mark A. & Olshevsky, George & Parrish, J. Michael & Weishampel, David B. ''The Age of Dinosaurs''. Publications International, LTD. p. 128. {{ISBN|0-7853-0443-6}}. * Holtz, TR Jr. (2001), "The phylogeny and taxonomy of the Tyrannosauridae" in: K Carpenter & D Tanke [eds.], ''Mesozoic Vertebrate Life''. Indiana Univ. Press, pp. 64–83. * Jacobsen, A.R. 2001. "Tooth-marked small theropod bone: An extremely rare trace". p. 58-63 In: ''Mesozoic Vertebrate Life''. Ed.s Tanke, D. H., Carpenter, K., Skrepnick, M. W. Indiana University Press.
{{Theropoda|C.}} {{Taxonbar|from=Q132625}}
Category:Tyrannosauridae Category:Dinosaur genera Category:Campanian dinosaurs Category:Judith River Formation Category:Fossil taxa described in 1868 Category:Taxa named by Joseph Leidy Category:Dinosaurs of the United States Category:Tooth taxa