PBDB Taxon

Basic info	Taxonomic history	Classification	Included Taxa
Morphology	Ecology and taphonomy	External Literature Search	Age range and collections

Oligotheriomys

Osteichthyes - Rodentia - Castoridae

Taxonomy

Oligotheriomys was named by Korth (1998). Its type is Oligotheriomys primus.

It was assigned to Agnotocastorinae by Korth (1998).

Species

O. magnus (syn. O. primus), O. senrudi

Entered

by J. Alroy on 2003-01-23; modified by J. Marcot on 2026-05-19

Synonymy list

Year	Name and author
1998	Oligotheriomys Korth

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Rank	Name	Author
kingdom	Animalia	()
—	Bilateria
—	Eubilateria	Ax 1987
—	Deuterostomia
phylum	Chordata	Haeckel 1874
subphylum	Vertebrata
superclass	Gnathostomata
class	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
—	Euarchontoglires	Murphy et al. 2001
—	Gliriformes	Wyss and Meng 1996
—	Glires	()
—	Simplicidentata	()
order	Rodentia
infraorder	Castorimorpha
superfamily	Castoroidea	Gray 1821
family	Castoridae
subfamily	Agnotocastorinae
genus	Oligotheriomys

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. †Oligotheriomys Korth 1998

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†Oligotheriomys magnus Wood 1937

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Invalid names: Oligotheriomys primus Korth 1998 [synonym]

†Oligotheriomys senrudi Wood 1945

Diagnosis

Reference	Diagnosis
W. W. Korth 1998	Agnotocastorine beaver similar to Anchitheriomys and differing from other agnoto- castorines in having a posterior maxillary notch rather than foramen, upper tooth rows diverge slightly posteriorly (not as much as in castorines, palaeocastorines, and castoroidines), upper molars unilaterally hypsodont, occlusal pattern of cheek teeth more complex (more fossettes), and hypoflexus much shallowerthanonotheragnotocastorines. Differsfrom Anchitheriomys in being much smaller (approximately half of all dental dimensions of Anchitheriomys), having cheek teeth lower crowned, P3 present (lost in Anchitheriomys), and lacking a deep mesoflexus on all upper molars (deep mesoflexus always present in Anchitheriomys).

Measurements

No measurements are available

Composition:

phosphaticsubp

Environment:

terrestrialsubc

Locomotion:

actively mobilec

Life habit:

amphibiousf

Diet:

browserf

Reproduction:

viviparoussubc

Created:

2005-06-08 10:11:09

Modified:

2005-08-26 13:05:29

Source: f = family, subc = subclass, c = class, subp = subphylum

References: Hendy et al. 2009, Lillegraven 1979, Ji et al. 2002, Carroll 1988, Nowak 1991

Age range: base of the Orellan to the top of the Middle Miocene or 33.90000 to 11.63000 Ma

Collections (6 total)

Time interval	Ma	Country or state	Original ID and collection number
Orellan	33.9 - 31.8	USA (North Dakota)	O. primus (17101)
Orellan	33.9 - 31.8	USA (South Dakota)	Eutypomys magnus (17115) O. magnus (17092)
Orellan	33.9 - 31.8	Canada (Saskatchewan)	Eutypomys magnus (17111)
Hemingfordian	18.5 - 16.3	USA (Wyoming)	Hystricops senrudi (17953)
Middle Miocene	15.98 - 11.63	USA (Montana)	Hystricops senrudi (18887)