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Merycochoerus

Mammalia - Merycoidodontidae

Taxonomy

Merycochoerus was named by Leidy (1858) [said by Cope 1884 to be a nomen nudum in Leidy 1858 and Leidy 1869, but validated by Leidy 1873; however, Cope then accepts 1858 as the correct date for M. proprius]. Its type is Merycochoerus proprius. It is the type genus of Merycochoerinae.

It was assigned to Merycoidodontinae by Hay (1902); to Oreodontidae by Leidy (1873), Cope (1884) and Scott (1913); to Merycoidodontidae by Leidy (1858), Thorpe (1937) and Lander (1998); and to Merycochoerinae by Schultz and Falkenbach (1940), Stevens and Stevens (2007) and Stevens et al. (2023).

Species

M. (Brachycrus), M. magnus, M. matthewi, M. pinensis, M. proprius (type species)

Synonyms

Merycochoerus (Brachycrus) was named by Matthew (1901) [named as a subgenus of Merycochoerus by Matthew 1901; raised to genus level]. Its type is Merycochoerus rusticus. It is the type subgenus of Brachycrurinae.

It was considered an invalid subgroup of Merycochoerus by Hay (1930); it was synonymized subjectively with Ticholeptus by Thorpe (1937); it was reranked as Brachycrus by Palmer (1904), Schultz and Falkenbach (1940), Simpson (1945), Schultz and Falkenbach (1968), Kelly and Lander (1988), Lander (1998), Stevens and Stevens (2007) and Stevens et al. (2023).

It was assigned to Merycochoerus by Matthew (1901); to Agriochoeridae by Palmer (1904); to Merycochoerinae by Schultz and Falkenbach (1940), Simpson (1945) and Schultz and Falkenbach (1968); to Merycoidodontidae by Kelly and Lander (1988) and Lander (1998); and to Brachycrurinae by Stevens and Stevens (2007) and Stevens et al. (2023).
Paracotylops was named by Matthew (1901) [in Merriam].

It was synonymized subjectively with Promerycochoerus by Loomis (1920), Thorpe (1921), Thorpe (1924), Thorpe (1937) and Schultz and Falkenbach (1949); it was synonymized subjectively with Merycochoerus by Lander (1998).
Pronomotherium was named by Douglass (1907).

It was reranked as Merycochoerus (Pronomotherium) by Merriam (1919); it was synonymized subjectively with Brachycrus by Schultz and Falkenbach (1940), Shotwell (1968) and Lander (1998).

It was assigned to Agriochoeridae by Douglass (1907); to Oreodontidae by Scott (1913); to Merycochoerus by Merriam (1919); and to Merycoidodontidae by Thorpe (1937).

Synonymy list

Year	Name and author
1858	Merycochoerus Leidy
1873	Merycochoerus Leidy p. 319
1884	Merycochoerus Cope p. 520
1901	Paracotylops Matthew
1901	Merycochoerus (Brachycrus) Matthew p. 397
1902	Merycochoerus Hay p. 667
1904	Brachycrus Palmer p. 141
1907	Pronomotherium Douglass
1913	Merycochoerus Scott p. 361
1913	Pronomotherium Scott p. 361
1919	Merycochoerus (Pronomotherium) Merriam p. 575
1937	Merycochoerus Thorpe p. 151
1937	Pronomotherium Thorpe p. 160
1940	Brachycrus Schultz and Falkenbach p. 218
1940	Merycochoerus Schultz and Falkenbach p. 277
1945	Brachycrus Simpson p. 149
1968	Brachycrus Schultz and Falkenbach p. 366
1988	Brachycrus Kelly and Lander
1998	Brachycrus Lander
1998	Merycochoerus Lander
2007	Merycochoerus Stevens and Stevens p. 160
2007	Brachycrus Stevens and Stevens p. 164
2023	Merycochoerus Stevens et al. p. 76
2023	Brachycrus Stevens et al. p. 104

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Rank	Name	Author
kingdom	Animalia	()
—	Bilateria
—	Eubilateria	Ax 1987
—	Deuterostomia
phylum	Chordata	Haeckel 1874
subphylum	Vertebrata
superclass	Gnathostomata
—	Osteichthyes	()
subclass	Sarcopterygii	()
subclass	Dipnotetrapodomorpha	(Nelson 2006)
subclass	Tetrapodomorpha	()
—	Tetrapoda
—	Reptiliomorpha
—	Anthracosauria
subclass	Amphibiosauria	Kuhn 1967
—	Cotylosauria	()
—	Amniota
subclass	Synapsida
—	Therapsida	()
infraorder	Cynodontia	()
—	Mammaliamorpha

Rank	Name	Author
—	Mammaliaformes
class	Mammalia
—	Theriamorpha	(Rowe 1993)
—	Theriiformes	()
—	Trechnotheria
—	Cladotheria
—	Zatheria
subclass	Tribosphenida	()
subclass	Theria
—	Eutheria	()
—	Placentalia
—	Boreoeutheria
—	Laurasiatheria
—	Scrotifera
—	Euungulata
—	Artiodactylamorpha
—	Artiodactyla	()
family	Merycoidodontidae
subfamily	Merycochoerinae
genus	Merycochoerus

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.

G. †Merycochoerus Leidy 1858

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†Merycochoerus magnus Loomis 1924

†Merycochoerus matthewi Loomis 1924

†Merycochoerus pinensis Schultz and Falkenbach 1949

†Merycochoerus proprius Leidy 1858

Invalid names: Merycochoerus (Brachycrus) Matthew 1901 [invalid subgroup], Paracotylops Matthew 1901 [synonym]

Diagnosis

Reference	Diagnosis
C. B. Schultz and C. H. Falkenbach 1940	SKULL.-Medium to very large size; brachycephalic; occipital region fan- shaped with supraoccipital crests protruding posteriorly; cranial region fore- shortened; brain case laterally expanded; frontals wide and moderately convex; zygomatic arches of medium to heavy construction; malars under orbits deep; nasals much reduced; infraorbital foramina above region of M 1 ; muzzle moder- ately to extremely deep; maxillre form a curve along the upper contour in advance of the anterior narial opening; pronounced extension of· the posterior palate to the pterygoid region; bullre inflated but small for size of skull. MANDIBLE.-Medium to large; long symphysis, with tuberosity on the posterior border. DENTITION-Brachyodont. LIMBs.-Moderately heavy to robust; feet vary from long and light to short and heavy.
M. S. Stevens et al. 2023	Medium to very large-sized oreodonts, with brachycephalic skulls, fan-shaped occipital regions with posteriorly protruding supraoccipital crests; short cranium with laterally expanded braincase, and wide convex frontals; heavy zygomatic arches with a deep malar beneath the orbits; nasals extremely reduced to small blunt curve in the derived species; maxillae forming a curve along the upper contour in front of the anterior narial opening; infraorbital foramen above M1; palate extended posteriorly to the pterygoid region; inflated bullae which are small in relation to the size of the skull.