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Ticholeptus zygomaticus

Mammalia - Merycoidodontidae

Taxonomy
Ticholeptus zygomaticus was named by Cope (1878) [genotype]. Its type specimen is AMNH 8112, a partial skull (Crushed skull (lacking nasals, frontals, and a portion of the occipital region) with I1-M3 (P1 br.) and mandible with i1-m3), and it is a 3D body fossil. It is the type species of Ticholeptus.

It was recombined as Merychyus zygomaticus by Cope (1884), Scott (1890), Scott (1893) and Hay (1902).

Synonyms
Synonymy list
YearName and author
1878Ticholeptus zygomaticus Cope p. 380
1884Merychyus zygomaticus Cope p. 545
1886Merycochoerus obliquidens Cope p. 359
1890Merychyus zygomaticus Scott
1893Merychyus zygomaticus Scott
1902Merycochoerus obliquidens Hay p. 668
1902Merychyus zygomaticus Hay p. 669
1903Merychyus smithi Douglass
1903Poatrephes paludicola Douglass
1906Ticholeptus zygomaticus Douglass p. 567
1907Ticholeptus zygomaticus Douglass
1920Ticholeptus zygomaticus Loomis
1924Ticholeptus hypsodus Loomis
1930Promerycochoerus obliquidens Hay
1937Ticholeptus hypsodus Thorpe p. 191 figs. Fig. 140
1937Ticholeptus obliquidens Thorpe p. 192 figs. PI. XXIX, figs. 5-6
1937Ticholeptus smithi Thorpe p. 197 figs. Fig. 144
1937Ticholeptus zygomaticus Thorpe p. 198 figs. PLXXIX,figs. 1-2
1937Poatrephes paludicola Thorpe p. 200 figs. Fig. 145 ; PI. XXVII, figs. 1-2
1941Ustatochoerus schrammi Schultz and Falkenbach p. 49
1941Ticholeptus hypsodus Schultz and Falkenbach p. 76
1941Ticholeptus obliquidens Schultz and Falkenbach p. 82
1941Ticholeptus rileyi Schultz and Falkenbach p. 83
1941Ticholeptus zygomaticus Schultz and Falkenbach p. 85
1941Ticholeptus zygomaticus smithi Schultz and Falkenbach p. 86
1968Ticholeptus hypsodus leadorensis Schultz and Falkenbach p. 375 figs. Figure 44
1988Ticholeptus zygomaticus Kelly and Lander
1988Merychyus elegans smithi Kelly and Lander p. 8
1998Merychyus smithi Lander
1998Ticholeptus zygomaticus Lander
2001Merychyus smithi Tabrum and Nichols
2007Ticholeptus zygomaticus Stevens and Stevens p. 164
2023Ticholeptus zygomaticus Stevens et al. p. 88 figs. Figures 71-74; Appendix 9A; Table A30

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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
subfamilyTicholeptinae
genusTicholeptus
specieszygomaticus

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.

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Invalid names: Merychyus smithi Douglass 1903 [synonym], Merycochoerus obliquidens Cope 1886 [synonym], Poatrephes paludicola Douglass 1903 [synonym], Ticholeptus hypsodus Loomis 1924 [synonym], Ticholeptus hypsodus leadorensis Schultz and Falkenbach 1968 [synonym], Ticholeptus rileyi Schultz and Falkenbach 1941 [synonym], Ustatochoerus schrammi Schultz and Falkenbach 1941 [synonym]
Diagnosis
ReferenceDiagnosis
C. B. Schultz and C. H. Falkenbach 1941 (Ticholeptus obliquidens)SKULL.-Unknown.
MANDIBLE.-Similar to those of T. zygomaticus and T. hypsodus; slightly smaller and shallower than in T. zygomaticus but nearly equal in size to small examples of T. hypsodus.
DENTITION.-Superior series unknown; inferior series slightly heavier and of less length than that of T. zygomaticus, and approximately equal in size and form to that of T. hypsodus.
LIMBS.-Unknown.
C. B. Schultz and C. H. Falkenbach 1941 (Ticholeptus hypsodus)SKULL.-Slightly shorter, but approximately same width as that of T. zygomaticus; frontals robust above orbits.
MANDIBL'E,-Similarto T. zygomaticus; slightly smaller.
DENTITION.-Superior and inferior series approximately same length as those of T. zygomaticus, but somewhat lighter.
LIMBS.-Heavier than those of T. rileyi and T. tooheyi.
C. B. Schultz and C. H. Falkenbach 1941 (Ticholeptus rileyi)
SKULL.-Unknown.
MANDIBLE.-Approximate size of that of T. hypsodus; ramus shallow (even shallower than in T. obliquidens and T. tooheyi); ascending ramus shallow and narrow anteroposteriorly; condyle light.
DENTITION.-Superior series unknown; inferior series approximate size of those of T. zygomaticus and T. hypsodus.
LIMBs.-Known only from a partial femur; lighter than examples of T. hypsodus.
C. B. Schultz and C. H. Falkenbach 1941
SKULL.-Slightly longer but approximately same width as that of T. hypsodus; zygomatic arch similar to that of T. hypsodus and more robust than in T. tooheyi; postglenoid process slightly lighter than in T. hypsodus.
MANDIBLE.-Equal to some examples of T. hypsodus.
DENTITION.-Superior and inferior series approximately equal to large examples of those of T. hypsodus, but slightly heavier and longer than average of that species.
LIMBS.-Unknown.
C. B. Schultz and C. H. Falkenbach 1941 (Ustatochoerus schrammi)MANDIBLE.-Smallest of the genus; lighter and shallower than examples of
U. medius.
DENTITION.-lnferior series smaller than those of U. medius but larger than
in any known species of Tichowptus; P2 and P3 with cusps typical of Ustato- choerus but P4 with these cusps only slightly developed.
LIMBs.-Unknown.
M. S. Stevens et al. 2023Largest species of Ticholeptus, with a more robust skull than T. tooheyi, and a slightly heavier dentition