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Merycochoerus matthewi

Mammalia - Merycoidodontidae

Taxonomy
Merycochoerus matthewi was named by Loomis (1924). Its type specimen is AM 12970, a partial skeleton (Skullwith I1(rt.)-M3 (lacking supraoccipital region), mandible with i1(br.)-m3, radius, ulna, manus, and skeletal fragments), and it is a 3D body fossil. Its type locality is AMNH Rosebud 18, which is in a Harrisonian terrestrial horizon in the Rosebud Formation of South Dakota.

Synonymy list
YearName and author
1924Merycochoerus matthewi Loomis
1937Merycochoerus matthewi Thorpe p. 156 figs. PI. XXIII, figs. 4-5
1940Merycochoerus matthewi Schultz and Falkenbach p. 289
2007Merycochoerus matthewi Stevens and Stevens p. 160
2023Merycochoerus matthewi Stevens et al. p. 79 figs. Figures 53, 62, 63; Appendix 7B; Table A27

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RankNameAuthor
kingdomAnimalia()
Bilateria
EubilateriaAx 1987
Life
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
subfamilyMerycochoerinae
genusMerycochoerus
speciesmatthewi

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.

Merycochoerus matthewi Loomis 1924
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Diagnosis
ReferenceDiagnosis
C. B. Schultz and C. H. Falkenbach 1940SKULL.-Smaller and somewhat lighter construction than in M. proprius; muzzle low in comparison with that of M. proprius and nasals not as retracted; maxillary notch of sigmoid curve, below nasals, retracted to a point above PLP 4 ; nasals nearly h6rizontal; brain case more rounded than in M. proprius.
MANDIBLE.-Lighter construction than average of M. proprius.
DENTITIONS.-Tendency to be lighter in construction than M. proprius; length of upper and lower series equal in length to smaller examples of M. proprius.
LIMBs.-Equal in length to those of M. proprius, but lighter; metapodials longer and lighter than examples of M. proprius.
M. S. Stevens et al. 2023Smallest (M1-3 length = 77-88 mm; P2-M3 length = 130-150 mm; m1-3 length = 90-100 mm; p2-m3 length = 135-141 mm) and mostly lightly built of the species of Merycochoerus, with a lower rostrum, and the nasals pointing forward (rather that inclined upward and forward), and flat and longer, rather than short and stubby as in M. magnus and M. proprius; narial notch not nearly as retracted, reaching only to the level of P3-4. Dorsal border of premaxillae and maxillary in the narial notch slopes anteroventrally, with no sigmoidal curve as in more advanced species.
Measurements
No measurements are available
Composition: phosphaticsubp
Environment: terrestrialo
Locomotion: actively mobilec
Life habit: ground dwellingf
Diet: herbivoref
Reproduction: viviparoussubc
Created: 2005-08-31 14:37:21
Modified: 2005-08-31 16:37:21
Source: f = family, o = order, subc = subclass, c = class, subp = subphylum
References: Carroll 1988, Nowak 1999, Lander 1998, Lillegraven 1979, Hendy et al. 2009

Age range: base of the Early/Lower Miocene to the top of the Middle Miocene or 23.03000 to 11.60800 Ma

Collections (14 total)


Time interval Ma Country or state Original ID and collection number
Arikareean30.8 - 20.43USA (Oregon) Merycochoerus matthewi (188964 188965)
Harrisonian24.8 - 20.43USA (South Dakota) Merycochoerus matthewi (type locality: 17749)
Harrisonian24.8 - 20.43USA (Nebraska) Merycochoerus matthewi (17738) Merycochoerus sp. (17809)
Harrisonian24.8 - 20.43USA (Wyoming) Merycochoerus matthewi (17793 17833 17839 17850)
Early/Lower Miocene23.03 - 15.97USA (Colorado) Merycochoerus matthewi (18978)
Early/Lower Hemingfordian20.43 - 15.97Panama (Panama City) Merycochoerus matthewi (144879)
Early/Lower Hemingfordian20.43 - 15.97Panama Merycochoerus sp. (18725)
Early/Lower Hemingfordian20.43 - 15.97USA (Oregon) Merycochoerus matthewi (17925)
Middle Miocene15.97 - 11.608USA (Colorado) Merycochoerus matthewi (18976)