PBDB Taxon

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Morphology	Ecology and taphonomy	External Literature Search	Age range and collections

Symmetrodontoides

Mammalia - Spalacotheriidae

Taxonomy

Symmetrodontoides was named by Fox (1976). It is not extant. Its type is Symmetrodontoides canadensis.

It was assigned to Spalacotheriida by Prothero (1981); to Spalacotheriidae by Fox (1976), Cassiliano and Clemens (1979), McKenna and Bell (1997) and Li and Luo (2006); and to Spalacolestinae by Cifelli and Madsen (1999), Averianov (2002), Kielan-Jaworowska et al. (2004) and Han and Meng (2016).

Species

S. canadensis (syn. Mictodon simpsoni) (type species), S. foxi, S. oligodontos

Synonyms

Mictodon was named by Fox (1984). It is not extant.

It was synonymized subjectively with Symmetrodontoides by Kielan-Jaworowska et al. (2004).

It was assigned to Tinodontidae by Fox (1984) and McKenna and Bell (1997).

Synonymy list

Year	Name and author
1976	Symmetrodontoides Fox
1979	Symmetrodontoides Cassiliano and Clemens p. 151
1981	Symmetrodontoides Prothero p. 320
1984	Mictodon Fox
1997	Mictodon McKenna and Bell
1997	Symmetrodontoides McKenna and Bell
1999	Symmetrodontoides Cifelli and Madsen pp. 174-179
2002	Symmetrodontoides Averianov p. 714
2004	Symmetrodontoides Kielan-Jaworowska et al. pp. 345, 370 fig. 9.10F
2006	Symmetrodontoides Li and Luo p. 197
2016	Symmetrodontoides Han and Meng

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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

Rank	Name	Author
—	Cotylosauria	()
—	Amniota
subclass	Synapsida
—	Therapsida	()
infraorder	Cynodontia	()
—	Mammaliamorpha
—	Mammaliaformes
class	Mammalia
—	Theriamorpha	(Rowe 1993)
—	Theriiformes	()
—	Trechnotheria
—	Spalacotherioidea
family	Spalacotheriidae	Marsh 1887
subfamily	Spalacolestinae
genus	Symmetrodontoides

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. †Symmetrodontoides Fox 1976

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†Symmetrodontoides canadensis Fox 1976

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Invalid names: Mictodon simpsoni Fox 1984 [synonym]

†Symmetrodontoides foxi Cifelli and Madsen 1986

†Symmetrodontoides oligodontos Cifelli 1990

Invalid names: Mictodon Fox 1984 [synonym]

Diagnosis

No diagnoses are available

Measurements

No measurements are available

Composition:

phosphaticsubp

Environment:

terrestrialc

Locomotion:

actively mobilec

Life habit:

scansorialuc

Diet:

insectivoreuc

Created:

2005-09-06 19:53:51

Modified:

2005-09-07 19:44:02

Source: c = class, subp = subphylum, uc = unranked clade

References: Luo et al. 2003, Hopson 1973, Hendy et al. 2009, Carroll 1988

Age range: base of the Coniacian to the top of the Judithian or 89.80000 to 70.60000 Ma

Collections (14 total)

Time interval	Ma	Country or state	Original ID and collection number
Late/Upper Turonian	93.5 - 89.3	USA (Utah)	Spalacotheriidae indet. (14415)
Middle Turonian	93.5 - 89.3	USA (Utah)	S. oligodontos (14416)
Middle Turonian - Late/Upper Turonian	93.5 - 89.3	USA (Utah)	Spalacotheriidae indet. (14414)
Coniacian - Santonian	89.8 - 83.6	USA (Utah)	S. sp. (14389)
Santonian	86.3 - 83.6	USA (Montana)	S. canadensis (181582)
Late/Upper Santonian	85.8 - 83.5	Canada (Alberta)	Mictodon simpsoni (14428) S. canadensis (14425)
Early/Lower Campanian	83.5 - 70.6	USA (Utah)	S. foxi (14429 75839 75840 75845) S. sp., S. foxi (14421)
Judithian	83.5 - 70.6	USA (Utah)	S. foxi (14474)
Late/Upper Campanian	83.5 - 70.6	USA (Utah)	Picopsis sp. (14466)