PBDB Taxon

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Leptauchenia

Mammalia - Merycoidodontidae

Taxonomy

Leptauchenia was named by Leidy (1856).

It was assigned to Merycoidodontinae by Hay (1902); to Oreodontidae by Cope (1884), Scott (1913); to Leptaucheniini by Schultz and Falkenbach (1968); to Merycoidodontidae by Leidy (1856), Thorpe (1937), Scott (1940), Lander (1998); and to Leptaucheniinae by Stevens and Stevens (2007), Prothero and Sanchez (2008).

Species

Cyclopidius (Chelonocephalus), Cyclopidius californicus, L. (Sespia), L. decora (syn. Pithecistes decedens, Pithecistes copei, Hadroleptauchenia primitiva, Pithecistes mariae, Pseudocyclopidius orellaensis, L. minora, L. harveyi, Pithecistes brevifacies, Pithecistes breviceps, Cyclopidius (Chelonocephalus) schucherti, L. parasimus, Cyclopidius loganensis, Hadroleptauchenia eiseleyi, Pithecistes tanneri, L. martini, Pithecistes altageringensis, Pithecistes facies), L. lullianus (syn. Pseudocyclopidius lullianus expiratus, Cyclopidius quadratus), L. major (syn. Cyclopidius simus, Hadroleptauchenia extrema, Hadroleptauchenia shanafeltae, Pseudocyclopidius frankforteri, L. margeryae, Cyclopidius incisivus, L. densa, Brachymeryx feliceps, Cyclopidius emydinus)

Synonyms

Pseudoleptauchenia was named by Unknown.

It was synonymized objectively with Leptauchenia by Lander (1998).
Brachymeryx was named by Cope (1877). It is not extant.

It was synonymized subjectively with Cyclopidius by Cope (1884), Hay (1902), Loomis (1924), Thorpe (1937), Koerner (1940), Schultz and Falkenbach (1968), McKenna and Bell (1997); it was synonymized subjectively with Leptauchenia by CoBabe (1996), Lander (1998), Prothero and Sanchez (2008).
Cyclopidius was named by Cope (1877). It is not extant. Its type is Cyclopidius simus.

It was synonymized subjectively with Leptauchenia by CoBabe (1996), Lander (1998), Prothero and Sanchez (2008).

It was assigned to Merycoidodontinae by Hay (1902); to Oreodontidae by Cope (1884), Scott (1913); to Merycoidodontidae by Thorpe (1937); and to Leptaucheniini by Schultz and Falkenbach (1968), McKenna and Bell (1997).
Hadroleptauchenia was named by Schultz and Falkenbach (1968).

It was synonymized subjectively with Leptauchenia by CoBabe (1996), Lander (1998), Prothero and Sanchez (2008).

It was assigned to Leptaucheniini by Schultz and Falkenbach (1968), McKenna and Bell (1997).
Pithecistes was named by Cope (1877). It is not extant.

It was synonymized subjectively with Cyclopidius by Matthew (1899), Hay (1902), Thorpe (1921), Loomis (1925), Schlaikjer (1935), Thorpe (1937), Koerner (1940); it was synonymized subjectively with Leptauchenia by CoBabe (1996), Lander (1998), Prothero and Sanchez (2008).

It was assigned to Oreodontidae by Cope (1884); and to Leptaucheniini by Schultz and Falkenbach (1968), McKenna and Bell (1997).
Pseudocyclopidius was named by Schultz and Falkenbach (1968).

It was synonymized subjectively with Leptauchenia by CoBabe (1996), Lander (1998), Prothero and Sanchez (2008).

It was assigned to Leptaucheniini by Schultz and Falkenbach (1968), McKenna and Bell (1997).

Synonymy list

Year	Name and author
1856	Leptauchenia Leidy
1877	Pithecistes Cope p. 219
1877	Brachymeryx Cope p. 220
1877	Cyclopidius Cope p. 221
1878	Brachymeryx Cope
1878	Pithecistes Cope
1884	Cyclopidius Cope p. 546
1884	Leptauchenia Cope p. 546
1884	Pithecistes Cope p. 557
1902	Cyclopidius Hay p. 670
1902	Leptauchenia Hay p. 670
1913	Cyclopidius Scott p. 361
1913	Leptauchenia Scott p. 361
1937	Leptauchenia Thorpe p. 234
1937	Cyclopidius Thorpe p. 241
1940	Leptauchenia Scott p. 690 figs. Plates LXXIV , LXXV
1968	Hadroleptauchenia Schultz and Falkenbach
1968	Pseudocyclopidius Schultz and Falkenbach
1968	Pithecistes Schultz and Falkenbach p. 258 figs. Figures 32, 38, 40, 53 ( skulls, mandibles, and dentitions)
1968	Leptauchenia Schultz and Falkenbach p. 272 figs. Figures 33, 38, 40, 41, 53 ( skulls, mandibles, and dentition) ; 43 ( skeletal elements)
1968	Cyclopidius Schultz and Falkenbach p. 296 figs. Figures 34, 38, 40, 41
1968	Hadroleptauchenia Schultz and Falkenbach p. 303 figs. Fgures 34, 35, 38, 40, 53, 55 (skulls, mandibular rami), and 43 (limbs)
1968	Pseudocyclopidius Schultz and Falkenbach p. 323 figs. Figures 36-40, 53 (skull, mandibular rami), and 43 (limbs)
1997	Cyclopidius McKenna and Bell p. 409
1997	Hadroleptauchenia McKenna and Bell p. 409
1997	Pithecistes McKenna and Bell p. 409
1997	Pseudocyclopidius McKenna and Bell p. 409
1998	Leptauchenia Lander
2007	Leptauchenia Stevens and Stevens p. 158
2008	Leptauchenia Prothero and Sanchez

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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	()

Rank	Name	Author
—	Mammaliamorpha
—	Mammaliaformes
class	Mammalia
—	Cladotheria
—	Zatheria
subclass	Tribosphenida	()
subclass	Theria
—	Eutheria	()
—	Placentalia
—	Boreoeutheria
—	Laurasiatheria
—	Scrotifera
—	Euungulata
—	Artiodactylamorpha
—	Artiodactyla	()
suborder	Tylopoda	()
family	Merycoidodontidae
subfamily	Leptaucheniinae	Schultz and Falkenbach 1940
genus	Leptauchenia

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. †Leptauchenia Leidy 1856

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Subg. †Leptauchenia (Sespia) Stock 1930

†Leptauchenia decora Leidy 1856

Invalid names: Cyclopidius (Chelonocephalus) schucherti Thorpe 1921 [synonym], Cyclopidius loganensis Koerner 1940 [synonym], Hadroleptauchenia eiseleyi Schultz and Falkenbach 1968 [synonym], Hadroleptauchenia primitiva Schultz and Falkenbach 1968 [synonym], Leptauchenia harveyi Schultz and Falkenbach 1968 [synonym], Leptauchenia martini Schultz and Falkenbach 1968 [synonym], Leptauchenia minora Schlaikjer 1935 [synonym], Leptauchenia parasimus Schultz and Falkenbach 1968 [synonym], Pithecistes altageringensis Schultz and Falkenbach 1968 [synonym], Pithecistes brevifacies Cope 1877 [synonym], Pithecistes copei Schultz and Falkenbach 1968 [synonym], Pithecistes decedens Cope 1884 [synonym], Pithecistes facies Cope 1888 [synonym], Pithecistes mariae Schultz and Falkenbach 1968 [synonym], Pithecistes tanneri Schultz and Falkenbach 1968 [synonym], Pseudocyclopidius orellaensis Schultz and Falkenbach 1968 [synonym]

†Leptauchenia lullianus Thorpe 1921

Invalid names: Cyclopidius quadratus Koerner 1940 [synonym], Pseudocyclopidius lullianus expiratus Schultz and Falkenbach 1968 [synonym]

†Leptauchenia major Leidy 1856

Invalid names: Brachymeryx feliceps Cope 1877 [synonym], Cyclopidius emydinus Cope 1884 [synonym], Cyclopidius incisivus Scott 1893 [synonym], Cyclopidius simus Cope 1877 [synonym], Hadroleptauchenia extrema Schultz and Falkenbach 1968 [synonym], Hadroleptauchenia shanafeltae Schultz and Falkenbach 1968 [synonym], Leptauchenia densa Loomis 1925 [synonym], Leptauchenia margeryae Schultz and Falkenbach 1968 [synonym], Pseudocyclopidius frankforteri Schultz and Falkenbach 1968 [synonym]

Invalid names: Brachymeryx Cope 1877 [synonym], Cyclopidius Cope 1877 [synonym], Hadroleptauchenia Schultz and Falkenbach 1968 [synonym], Pithecistes Cope 1877 [synonym], Pseudocyclopidius Schultz and Falkenbach 1968 [synonym], Pseudoleptauchenia Unknown [objective synonym]

Diagnosis

Reference	Diagnosis
D. R. Prothero and F. Sanchez 2008	(modified from CoBabe, 1996, and Lander, 1998) Small to moderate-sized oreodonts with a greatly enlarged pair of nasal-facial vacuities enclosed by the nasal, frontal, premaxillary, and maxillary bones; fan-shaped occipital region; orbit elevated high on the skull; inflated auditory bullae; external auditory meatus tube long, large, elevated and posteriorly directed; deep zygomatic arch and malar bone; teeth hypsodont to extremely hypsodont, with thin occlusal enamel. I1 reduced or absent; P1-3 anteriorly shortened, nearly square, with central fossette; M1-3 lingual selenes rounded, closely appressed, broadly con- tinuous, forming a single crest extending toward the mesostyle, and off- set posteriorly relative to labial selenes. Differs from Sespia in having a larger body size, wider and thicker zygomatic arch (malar bone) than Sespia, and teeth which are not as hypsodont, but have more prominent styles on M1-3 and stylids on m1-3.