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Merycoidodon (Otarohyus) major

Mammalia - Ungulata - Merycoidodontidae

Oreodon major was named by Leidy (1853) [also said to be 1854]. Its type specimen is USNM 19099, a maxilla, and it is a 3D body fossil.

It was recombined as Eporeodon major by Marsh (1875), Hay (1902), Thorpe (1921), Thorpe (1924), Thorpe (1937), Scott (1940) and Galbreath (1953); it was recombined as Eucrotaphus major by Cope (1884); it was recombined as Eucrotaphus (Oreodon) major by Scott and Osborn (1887); it was recombined as Paramerycoidodon (Barbourochoerus) major by Schultz and Falkenbach (1968); it was recombined as Mesoreodon major by Fremd (1994) and Lander (1998); it was recombined as Merycoidodon (Otarohyus) major by Stevens and Stevens (1996); it was recombined as Merycoidodon major by Stevens and Stevens (2007).

Synonymy list
YearName and author
1853Oreodon major Leidy
1856Oreodon major Leidy p. 164
1857Oreodon major Leidy p. 89
1869Oreodon hybridus Leidy
1873Oreodon major Leidy p. 211
1873Oreodon hybridus Leidy p. 212
1875Eporeodon major Marsh p. 250
1884Eucrotaphus major Cope p. 517
1887Eucrotaphus (Oreodon) major Scott and Osborn p. 155
1902Merycoidodon hybridus Hay p. 666
1902Eporeodon major Hay p. 667
1921Eporeodon major Thorpe
1924Eporeodon hybridus Thorpe
1924Eporeodon major Thorpe
1937Eporeodon major Thorpe p. 74 figs. Fig. 7 ; PI. VI, figs. 1-3
1937Eporeodon major hybridus Thorpe p. 77 figs. Fig. 38
1940Eporeodon major Scott p. 679
1949Promesoreodon scanloni Schultz and Falkenbach p. 152 figs. 21-25
1953Eporeodon major Galbreath
1954Pseudodesmatochoerus milleri Schultz and Falkenbach p. 209 figs. 12-15, 18
1954Subdesmatochoerus shannonensis Schultz and Falkenbach p. 223 figs. 19 - 21
1968Genetochoerus (Osbornohyus) chamberlaini Schultz and Falkenbach
1968Otionohyus (Otarohyus) alexi Schultz and Falkenbach
1968Paramerycoidodon (Barbourochoerus) major Schultz and Falkenbach p. 92 figs. igures 6-9, 1~23, 52
1968Paramerycoidodon (Gregoryochoerus) wanlessi Schultz and Falkenbach p. 99 figs. Fgures 6-9, 19, 52
1968Otionohyus (Otarohyus) hybridus Schultz and Falkenbach p. 129 figs. Figures 11-13, 19-23
1968Otionohyus (Otarohyus) alexi Schultz and Falkenbach p. 132 figs. F:igures 11-13, 52
1968Genetochoerus (Osbornohyus) chamberlaini Schultz and Falkenbach p. 152 figs. Fgures 14-16
1994Mesoreodon major Fremd
1996Merycoidodon (Otarohyus) major Stevens and Stevens p. 529 figs. Figures 2D, 3D; Tables 1-7; Appendix B
1998Mesoreodon major Lander
2007Merycoidodon major Stevens and Stevens p. 160

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phylumChordataHaeckel 1847
subclassDipnotetrapodomorpha(Nelson 2006)
orderUngulata(Linnaeus 1766)
speciesmajor(Leidy 1853)

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.

C. B. Schultz and C. H. Falkenbach 1949 (Promesoreodon scanloni)SKULL: Small; see generic characters.
MANDIBLE: Light; see generic characters.
DENTITION:Brachyodont; series of less length than that in known species of Mesoreo- don; pa with anterior internal pits and P' with external anterior pit (not observable in well-worn specimens).
LIMBS: Short and light, equal to small examples of Merycoidodon culbertsonii.
C. B. Schultz and C. H. Falkenbach 1954 (Pseudodesmatochoerus milleri)SKULL: Medium size; tendency to be slightly smaller than examples of P. koffmani, larger than in P. longiceps; supraoccipital wings with less spread than in P. longiceps; sagittal crest with slightly depressed medial region, not so pronounced as in examples of P. koffmani; nasals long and light, with slight anterior retraction, less retraction than in latter species; anterior nasal-maxilla contact above P1, slightly more anterior than in examples of P. koffmani; infraorbital foramen above PLP 4; bulla of moderate size, smaller than other examples of genus; post-glenoid process more peg-shaped than in examples of P. kojfmani (closer to that of P. longiceps in this respect, but with less height).
MANDIBLE: Postsymphysis below anterior portion of Pa; posterior border of ascending ramus lighter than in P. longiceps. ·
DENTITION: Series approximately same size as examples of P. koffmani, larger than in P. longiceps, slightly longer than in P. wascoensis; more robust than in latter two species.
LIMBS: (Unknown).
C. B. Schultz and C. H. Falkenbach 1954 (Subdesmatochoerus shannonensis)SKULL: Slightly larger than in S. socialis, smaller than that of holotype of S. montanus; exoccipital vacuities moderately large, smaller than those in S. montanus; zygomatic arch with less abrupt posterior rise and inward notch below posterior aspect of orbit more pronounced than in S. socialis; paroccipital process heavier at base than in that species; bulla similar to that in S. socialis except for less prominent external posterior groove and pit for hyoid attachment.
MANDIBLE: Slightly smaller than in holotype of S. montanus; larger than other forms of the genus.
DENTITION: Series with average length greater than that in S. socialis; anterior intermediate crests on PLP 3 each well de- veloped (a remnant of an analogous crest indicated in unworn C/).
LIMBS: Slightly larger and more robust than in S. socialis. (Known from fragmentary specimens only.)
M. S. Stevens and J. B. Stevens 1996The cranial characterization is the same as for the genus-subgenus, but the skull trends toward massiveness, with broad frontals and muzzle, widely spread zygomatic arches, well inflated auditory bullae which lack distinct hyoidal grooves, and small and generally pit-like preorbital fossae. The Subnasal L. averages 51.5% of the Nasal L. (13 specimens), the pl_P4;pLM3 averages 48.4% (Table 3), the APM3/ TM3 ratio averages 1.02 (Table 5), the mean APM3/Ht. M3 ratio is 1.68 (Table 4), and TM3/Ht. M3 averages 1.63 (Table 6).Merycoidodonmajor differs from Merycoidodon bullatus by a substantially (on the average , means of M . bullatus lie 1.7 SDs below those of Merycoidodon major; basis: SDs of M. major), and in terms of measurement means, systematically , larger size (significant for all measurement means except that of Nasal L.), a usually broader P.O.C., slightly but significantly more reduced premolars, and the cranial features noted above,otherwise similar. Merycoidodon major differs from Mesoreodon chelonyx by a system- atically smaller size (means average about 0.9 SDs of M . major smaller; signific ant: pl-M3, pl_P4 , MI -M3, APM3s, Ht. M3, and Nasal L.), significantly less anteroposteriorly attenuated M3s, and slightly lower crowned teeth , otherwise very similar.
No measurements are available
Composition: phosphaticsubp
Environment: terrestrialo
Locomotion: actively mobilec
Life habit: ground dwellingf
Diet: herbivoref
Created: 2005-08-31 14:37:21
Modified: 2005-08-31 16:37:21
Source: f = family, o = order, c = class, subp = subphylum
References: Nowak 1999, Lander 1998, Carroll 1988, Hendy et al. 2009

Age range: base of the Orellan to the top of the Arikareean or 33.90000 to 20.43000 Ma

Collections (30 total)

Time interval Ma Country or state Original ID and collection number
Orellan33.9 - 33.3USA (Nebraska) Genetochoerus norbeckensis (17222)
Orellan33.9 - 33.3USA (North Dakota) Genetochoerus norbeckensis (17101)
Whitneyan33.3 - 30.8USA (Wyoming) Merycoidodon major (17383)
Whitneyan33.3 - 30.8USA (Colorado) Eporeodon major (17426)
Whitneyan33.3 - 30.8USA (South Dakota) Eporeodon major (17343) Genetochoerus chamberlaini (17348) Merycoidodon lynchi (17355) Paramerycoidodon major (17317 17324 17339 17340 17353 17370 17378 17380 17387 17431) Paramerycoidodon wanlessi (17360 17364)
Whitneyan33.3 - 30.8USA (Nebraska) Genetochoerus chamberlaini (17401 17435) Merycoidodon lynchi (17409 17418) Otionohyus alexi (17417) Paramerycoidodon major (17419 17421) Paramerycoidodon wanlessi (17408) Subdesmatochoerus shannonensis (17376)
Arikareean30.8 - 20.43USA (Wyoming) Pseudodesmatochoerus milleri (17524 17532)