PBDB Taxon

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Morphology	Ecology and taphonomy	External Literature Search	Age range and collections

Serridentinus floridanus

Osteichthyes - Proboscidea - Gomphotheriidae

Discussion

Mastodon (Trilophodon) floridanus

Taxonomy

Mastodon (Trilophodon) floridanus was named by Leidy (1886). It is a 3D body fossil. Its type locality is Mixson's Bone Bed, which is in a Hemphillian terrestrial horizon in the Alachua Formation of Florida.

It was recombined as Mastodon floridanus by Leidy and Lucas (1896); it was recombined as Mammut floridanum by Hay (1902); it was recombined as Serridentinus floridanus by Osborn (1923) and Gazin and Collins (1950); it was recombined as Trilophodon (Serridentinus) floridanus by Frick (1926); it was recombined as Ocalientinus floridanus by Osborn (1936); it was recombined as Amebelodon floridanus by Turner (1975), Shoshani and Tassy (1996), Lambert and Shoshani (1998); it was recombined as Stenobelodon floridanus by Lambert (2023), Eshelman et al. (2026).

Synonyms

Amebelodon sinclairi was named by Barbour (1930).

It was synonymized subjectively with Amebelodon fricki by Voorhies (1990); it was synonymized subjectively with Amebelodon floridanus by Shoshani and Tassy (1996).
Trilophodon (Serridentinus) leidii was named by Frick (1926). Its type specimen is USNM 3064, a tooth, and it is a 3D body fossil. Its type locality is Mixson's Bone Bed, which is in a Hemphillian terrestrial horizon in the Alachua Formation of Florida.

It was recombined as Ocalientinus floridanus leidii by Osborn (1936); it was synonymized subjectively with Amebelodon floridanus by Turner (1975).
Trilophodon hicksi was named by Cook (1922).

It was recombined as Amebelodon hicksi by Barbour and Hibbard (1941); it was synonymized subjectively with Amebelodon floridanus by Shoshani and Tassy (1996), Lambert and Shoshani (1998).
Trilophodon paladentatus was named by Cook (1922).

It was recombined as Amebelodon paladentatus by Frick (1933), Barbour and Hibbard (1941); it was synonymized subjectively with Amebelodon hicksi by Tedford et al. (1987); it was synonymized subjectively with Amebelodon floridanus by Shoshani and Tassy (1996), Lambert and Shoshani (1998).

Synonymy list

Year	Name and author
1886	Mastodon (Trilophodon) floridanus Leidy p. 12
1896	Mastodon floridanus Leidy and Lucas p. 15
1902	Mammut floridanum Hay p. 710
1922	Trilophodon hicksi Cook
1922	Trilophodon paladentatus Cook
1923	Serridentinus floridanus Osborn p. 2
1926	Trilophodon (Serridentinus) floridanus Frick p. 169
1926	Trilophodon (Serridentinus) leidii Frick p. 169
1930	Amebelodon sinclairi Barbour
1933	Amebelodon paladentatus Frick p. 609
1936	Ocalientinus floridanus Osborn p. 416
1936	Ocalientinus floridanus leidii Osborn p. 419
1941	Amebelodon hicksi Barbour and Hibbard
1941	Amebelodon paladentatus Barbour and Hibbard
1950	Serridentinus floridanus Gazin and Collins
1975	Amebelodon floridanus Turner p. 44
1996	Amebelodon floridanus Shoshani and Tassy
1998	Amebelodon floridanus Lambert and Shoshani p. 613
2023	Stenobelodon floridanus Lambert p. 2
2026	Stenobelodon floridanus Eshelman et al. p. 145

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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	()

Rank	Name	Author
infraorder	Cynodontia	()
—	Mammaliamorpha
—	Mammaliaformes
class	Mammalia
—	Cladotheria
—	Zatheria
subclass	Tribosphenida	()
subclass	Theria
—	Eutheria	()
—	Placentalia
superorder	Afrotheria
—	Paenungulatomorpha
superorder	Paenungulata
—	Tethytheria
order	Proboscidea	()
family	Gomphotheriidae	Hay 1922
genus	Serridentinus
species	floridanus	()

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.

†Serridentinus floridanus Leidy 1886

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Invalid names: Amebelodon sinclairi Barbour 1930 [synonym], Trilophodon hicksi Cook 1922 [synonym], Trilophodon leidii Frick 1926 [synonym], Trilophodon paladentatus Cook 1922 [synonym]

Diagnosis

Reference	Diagnosis
W. D. Lambert 2023	Third molar moderately elongated (5–5 + lophs/ lophids rather than 3–4 + lophs/lophids such as is found in Gom- photherium); lophs/lophids on the third molar weakly double- trefoiled (see explanation below), though not down the entire tooth length; intermediate cheek teeth (P/p4–M/m2) trilopho- dont; cheek teeth serridentine (cones, conules, and accessory conules tending to subdivide and form serrated crests within the loph structure; see discussion below); mandibular symphysis relatively slender, with modest widening at its anterior end and shallow suprasymphyseal ridges; lower tusks relatively narrow, much like Gomphotherium in overall proportions, and only mod- estly flattened by comparison with other shovel-tusked gom- photheres such as Konobelodon and Amebelodon; lower tusk with a conservative laminar internal structure like that found in Gomphotherium; upper tusk with a prominent lateral enamel band, and largely indistinguishable from Gomphotherium and other conservative gomphotheres.

Measurements

No measurements are available

Composition:

phosphaticsubp

Environment:

terrestrialsubc

Locomotion:

actively mobilec

Life habit:

ground dwellingg

Diet:

browserg

Reproduction:

viviparoussubc

Created:

2005-08-31 15:16:35

Modified:

2005-08-31 22:16:35

Source: g = genus, subc = subclass, c = class, subp = subphylum

References: Carroll 1988, Lambert and Shoshani 1998, Ji et al. 2002, Hendy et al. 2009, Lillegraven 1979

Age range: base of the Serravallian to the top of the Tortonian or 13.82000 to 7.24600 Ma

Collections (13 total)

Time interval	Ma	Country or state	Original ID and collection number
Miocene	23.04 - 5.333	USA (Florida)	Serridentinus floridanus (18530)
Serravallian	13.82 - 11.63	USA (Maryland)	Stenobelodon floridanus (70546 278687)
Tortonian	11.63 - 7.246	USA (Florida)	Serridentinus floridanus (18505)
Hemphillian	9.4 - 4.7	USA (Texas)	Amebelodon hicksi (18198)
Hemphillian	9.4 - 4.7	USA (Montana)	Amebelodon hicksi (18870)
Hemphillian	9.4 - 4.7	USA (Kansas)	Stenobelodon floridanus (18415)
Hemphillian	9.4 - 4.7	USA (Colorado)	Amebelodon hicksi (18495)
Hemphillian	9.4 - 4.7	USA (Idaho)	Amebelodon floridanus (19085)
Hemphillian	9.4 - 4.7	USA (Florida)	Amebelodon floridanus (26549) Mastodon floridanus (216990) Mastodon floridanus, Trilophodon leidii (18563) Serridentinus floridanus (18529)