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Merychyinae

Mammalia - Merycoidodontidae

Synonymy list
YearName and author
1945Merychyinae Simpson p. 149
1947Merychyinae Schultz and Falkenbach p. 168
1996Merychyinae Stevens and Stevens p. 510
2003Merychyinae Parris and Grandstaff p. 63
2007Merychyinae Stevens and Stevens p. 165
2023Merychyinae Stevens et al. p. 31

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RankNameAuthor
kingdomAnimalia()
Bilateria
EubilateriaAx 1987
Deuterostomia
phylumChordataHaeckel 1874
subphylumVertebrata
superclassGnathostomata
Osteichthyes()
subclassSarcopterygii()
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda
Reptiliomorpha
Anthracosauria
subclassAmphibiosauriaKuhn 1967
Cotylosauria()
Amniota
subclassSynapsida
Therapsida()
infraorderCynodontia()
Mammaliamorpha
RankNameAuthor
Mammaliaformes
classMammalia
Theriamorpha(Rowe 1993)
Theriiformes()
Trechnotheria
Cladotheria
Zatheria
subclassTribosphenida()
subclassTheria
Eutheria()
Placentalia
Boreoeutheria
Laurasiatheria
Scrotifera
Euungulata
Artiodactylamorpha
Artiodactyla()
familyMerycoidodontidae
subfamilyMerychyinae
subfamilyMerychyinae

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

Subfm. †Merychyinae Simpson 1945
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G. †Merychyus Leidy 1858
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Subg. †Merychyus (Metoreodon) Matthew and Cook 1909
Merychyus arenarum Cope 1884
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Invalid names: Merychyus arenarum idahoensis Schultz and Falkenbach 1947 [invalid subgroup], Merychyus arenarum leptorhynchus Cope 1884 [invalid subgroup], Merychyus euryops Cope 1899 [synonym]
Merychyus calaminthus Jahns 1940
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Invalid names: Merychyus crabilli Schultz and Falkenbach 1947 [synonym], Merychyus crabilli ziaensis Schultz and Falkenbach 1968 [synonym], Merychyus jahnsi Whistler 1967 [synonym]
Merychyus elegans Leidy 1858
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Invalid names: Merychyus paniensis Loomis 1924 [synonym]
Merychyus minimus Peterson 1907
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Invalid names: Merychyus delicatus Loomis 1924 [synonym]
Merychyus relictus Matthew and Cook 1909
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Invalid names: Merychyus (Metoreodon) relictus taylori Schultz and Falkenbach 1947 [invalid subgroup]
Merychyus verrucomalus Stevens 1970
Invalid names: Merychyus (Metoreodon) relictus fletcheri Schultz and Falkenbach 1947 [invalid subgroup], Metoreodon Matthew and Cook 1909 [synonym]
G. †Oreodontoides Thorpe 1921
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Oreodontoides curtus Loomis 1924
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Invalid names: Desmatochoerus anthyonyi Schultz and Falkenbach 1968 [synonym]
G. †Paramerychyus Schultz and Falkenbach 1947
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Paramerychyus harrisonensis Peterson 1907
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Invalid names: Merychyus siouxensis Loomis 1924 [synonym]
Paramerychyus relictus Loomis 1924
Diagnosis
ReferenceDiagnosis
C. B. Schultz and C. H. Falkenbach 1947Oreodonts of small to medium size; skulls mesocephalic; occipital region showing much variation with the supraoccipital wings in- corporated into a fan-shaped occipital; orbits large for size of skull; tendency for slight retraction of the nasals (anterior tip above C/); tympanic bulla well inflated and large, with a round to somewhat flattened inferior surface; teeth moderately large, brachyodont to subhypsodont (all the teeth in Merychyinae are in reality brachyodont, and the terms subhypsodont and brachyodont used in this paper are strictly comparative terms), premolars with simple to complicated patterns, the latter type found in the later Miocene species; PLP3 with anterior intermediate crest and Pa with posterior intermediate crest.
M. S. Stevens et al. 2023Small size (the smallest known Mioceneoreodonts), with shortened faces, slightly retracted nasals, wideinflated braincase with low sagittal crests, delicate zygomaticarches, arched frontal profile, small facial vacuities, a broadshallow lacrimal fossa anterior to the orbit, which forms a flat-bottomed depression. They have greatly inflated auditory bullaewith a “swollen” external auditory meatus, which completelyfills the space between the postglenoid and paroccipitalprocesses. The bulla is an inflated, sac-like structure with aslightly convex or flattened ventral surface that has a slightanteromedial slope. They have a relatively broad and fan-shapedoccipital region. The dentition is characterized by a longer molarrow that becomes quite hypsodont in later forms, and reducedpremolars, small caniniform teeth, and relatively long, delicate,slender limbs compared to most other larger Miocene oreodonts.