PBDB Taxon

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Morphology	Ecology and taphonomy	External Literature Search	Age range and collections

Ischyromys

Mammalia - Rodentia - Ischyromyidae

Taxonomy

Ischyromys was named by Leidy (1856). Its type is Ischyromys typus.

It was assigned to Protomyidae by Cope (1879); to Ischyromyinae by Wang et al. (1998); and to Ischyromyidae by Leidy (1856), Hay (1902), Lambe (1908), Johnson (1966), McKenna and Bell (1997), Korth and Emry (2007), Kihm (2013), Korth (2014), Lofgren et al. (2020) and Korth et al. (2022).

Species

I. blacki, I. brevidens, I. douglassi, I. junctus, I. parvidens, I. typus (syn. Colotaxis cristatus, I. pliacus, Gymnoptychus chrysodon, I. troxelli) (type species), I. typus nanus, I. veterior (syn. Titanotheriomys wyomingensis)

Synonyms

Ischyromys typus nanus was named by Troxell (1922). It is a 3D body fossil.

It was considered a nomen dubium by Heaton (1996).
Colotaxis was named by Cope (1873).

It was synonymized subjectively with Ischyromys by Cope (1881), Hay (1902), Matthew (1910), Troxell (1922), Wood (1937), Howe (1966), Black (1968), Wood (1980) and Heaton (1996).
Gymnoptychus was named by Cope (1873).

It was synonymized subjectively with Ischyromys by Hay (1899), Hay (1902), Matthew (1910), Troxell (1921), Wood (1937), Howe (1966), Black (1968), Wood (1980) and Heaton (1996).

It was assigned to Rodentia by Cope (1873).
Ischyromys parvidens was named by Miller and Gidley (1920).

It was synonymized subjectively with Titanotheriomys veterior by Black (1968); it was considered a nomen dubium by Heaton (1996).
Titanotheriomys was named by Miller and Gidley (1920) [named as subgenus by Matthew 1910b; raised to genus level].

It was synonymized subjectively with Ischyromys by Wood (1969), Korth (1994) and Heaton (1996).

It was assigned to Ischyromyinae by Wang et al. (1998).

Synonymy list

Year	Name and author
1856	Ischyromys Leidy
1873	Colotaxis Cope
1873	Gymnoptychus Cope
1879	Ischyromys Cope p. 45
1902	Ischyromys Hay p. 725
1908	Ischyromys Lambe
1920	Ischyromys parvidens Miller and Gidley
1920	Titanotheriomys Miller and Gidley
1922	Ischyromys typus nanus Troxell
1966	Ischyromys Johnson p. 80
1976	Titanotheriomys Wood
1980	Ischyromys parvidens Wood
1980	Titanotheriomys Wood
1993	Ischyromys parvidens Heaton
1994	Ischyromys parvidens Korth
1997	Ischyromys McKenna and Bell
1998	Ischyromys Wang et al.
1998	Titanotheriomys Wang et al.
2007	Ischyromys Korth and Emry
2013	Ischyromys Kihm
2014	Ischyromys Korth p. 374
2020	Ischyromys Lofgren et al.
2022	Ischyromys Korth et al.

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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
—	Theriamorpha	(Rowe 1993)
—	Theriiformes	()
—	Trechnotheria
—	Cladotheria
—	Zatheria
subclass	Tribosphenida	()
subclass	Theria
—	Eutheria	()
—	Placentalia
—	Boreoeutheria
—	Euarchontoglires	Murphy et al. 2001
—	Gliriformes	Wyss and Meng 1996
—	Glires	()
—	Simplicidentata	()
order	Rodentia	Bowdich 1821
family	Ischyromyidae	Alston 1876
genus	Ischyromys

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. †Ischyromys Leidy 1856

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†Ischyromys blacki Wood 1974

†Ischyromys brevidens Korth et al. 2022

†Ischyromys douglassi Black 1968

†Ischyromys junctus Russell 1972

†Ischyromys typus Leidy 1856

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Invalid names: Colotaxis cristatus Cope 1873 [synonym], Gymnoptychus chrysodon Cope 1873 [synonym], Ischyromys pliacus Troxell 1922 [synonym], Ischyromys troxelli Wood 1937 [synonym], Ischyromys typus lloydi Troxell 1922 [invalid subgroup]

†Ischyromys veterior Matthew 1903

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Invalid names: Titanotheriomys wyomingensis Wood 1937 [synonym]

Invalid names: Colotaxis Cope 1873 [synonym], Gymnoptychus Cope 1873 [synonym], Ischyromys parvidens Miller and Gidley 1920 [nomen dubium], Ischyromys typus nanus Troxell 1922 [nomen dubium], Titanotheriomys Miller and Gidley 1920 [synonym]

Diagnosis

No diagnoses are available

Measurements

No measurements are available

Composition:

phosphaticsubp

Environment:

terrestrialsubc

Locomotion:

actively mobilec

Life habit:

ground dwellingo

Diet:

herbivoreo

Reproduction:

viviparoussubc

Created:

2005-08-26 14:04:46

Modified:

2005-08-26 16:04:46

Source: o = order, subc = subclass, c = class, subp = subphylum

References: Nowak 1999, Lillegraven 1979, Carroll 1988, Hendy et al. 2009, Ji et al. 2002

Age range: base of the Late/Upper Uintan to the top of the Whitneyan or 46.20000 to 30.80000 Ma

Collections (123 total)

Time interval	Ma	Country or state	Original ID and collection number
Late/Upper Uintan	46.2 - 39.7	USA (Montana)	I. sp. (16584)
Duchesnean	39.7 - 37.0	USA (Texas)	I. blacki (16819 16821)
Duchesnean	39.7 - 37.0	USA (Wyoming)	I. sp. (16853 16884)
Duchesnean	39.7 - 37.0	Canada (Saskatchewan)	I. sp. (16845)
Duchesnean	39.7 - 37.0	USA (California)	I. sp. (17039)
Duchesnean - Chadronian	39.7 - 33.9	USA (Montana)	I. douglassi (16840)
Duchesnean - Early/Lower Chadronian	39.7 - 33.9	USA (Montana)	I. douglassi (230862)
Duchesnean - Early/Lower Chadronian	39.7 - 33.9	USA (Wyoming)	I. sp. (16881)
Chadronian	37.2 - 33.9	USA (South Dakota)	I. sp. (16885)
Chadronian	37.2 - 33.9	USA (Texas)	Titanotheriomys veterior (16894)
Chadronian	37.2 - 33.9	USA (Colorado)	I. troxelli, Titanotheriomys veterior (16977)
Chadronian	37.2 - 33.9	Canada (Saskatchewan)	I. junctus (16919)
Chadronian	37.2 - 33.9	USA (Wyoming)	I. parvidens (16943) I. sp. (16961) I. typus (16922 16986) I. veterior (16952 16955 17009) Titanotheriomys sp. (16901 16966) Titanotheriomys veterior (16920 16942 16960 16962 16963 16964 16965) Titanotheriomys wyomingensis (16902 16908)
Chadronian	37.2 - 33.9	USA (Montana)	I. douglassi (16990) I. pliacus, I. pliacus, Titanotheriomys veterior (17028) I. sp. (16927 16949) I. sp., I. veterior (16959 17010 17041) I. sp., Titanotheriomys veterior (16935) I. veterior, I. typus (16988) Titanotheriomys sp. (16946) Titanotheriomys veterior, I. pliacus (16924)
Chadronian	37.2 - 33.9	USA (North Dakota)	I. junctus, I. veterior (16991)
Chadronian	37.2 - 33.9	USA (Nebraska)	I. douglassi, I. veterior (17014) I. pliacus, Titanotheriomys wyomingensis (16929) I. sp. (17033) I. veterior (16917 16930 16940 17031)
Early/Lower Chadronian	37.2 - 33.9	USA (Montana)	I. douglassi (27245)
Late/Upper Chadronian	37.2 - 33.9	USA (Colorado)	I. douglassi, I. typus (85117)
Middle Chadronian	37.2 - 33.9	Canada (Saskatchewan)	I. veterior (16928)
Middle Chadronian - Late/Upper Chadronian	37.2 - 33.9	USA (Colorado)	I. sp. (156988)
Late/Upper Chadronian - Orellan	37.2 - 33.3	USA (Nebraska)	I. brevidens (230806)
Orellan	33.9 - 33.3	USA (Nebraska)	I. lloydi (17150) I. parvidens (17098 17203 17225 17226 17231 17235 17247 17255 17256 17271 17273 17279 17282 17283) I. pliacus (17242 17244 17250) I. typus (17062 17108 17164 17165 17212 17216 17223 17249 17253 17257 17275 17287 17297)
Orellan	33.9 - 33.3	USA (Montana)	I. sp. (17090)
Orellan	33.9 - 33.3	USA (South Dakota)	I. parvidens (17162) I. pliacus (17115) I. sp. (17136 17153 17186 17187 17188 17189 17190 17198 163487) I. troxelli (17179) I. typus (17094 17102 17103 17133 17173 17174 17182 17295) Rodentia indet. (17089)
Orellan	33.9 - 33.3	USA (Colorado)	I. typus (17082) I. typus, Titanotheriomys sp. (17081)
Orellan	33.9 - 33.3	USA (Wyoming)	I. parvidens (17104 17105 17106) I. pliacus (17086)
Orellan	33.9 - 33.3	USA (North Dakota)	I. sp. (17301) I. typus (17100 17101)
Whitneyan	33.3 - 30.8	USA (South Dakota)	I. pliacus (17336) I. sp. (17384) I. typus (170168)
Whitneyan	33.3 - 30.8	USA (Nebraska)	I. sp. (17414) I. typus (17427)