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Paleoparadoxia

Osteichthyes - Perissodactyla - Paleoparadoxiidae

Taxonomy

Paleoparadoxia was named by Reinhart (1959) [Sepkoski's age data: T Mi-m T Mi-u]. Its type is Archaeoparadoxia weltoni. It was considered monophyletic by Beatty (2009).

It was assigned to Paleoparadoxidae by Reinhart (1959); to Cornwalliidae by Shikama (1966); to Desmostylidae by Carroll (1988), Inuzuka et al. (1995), McKenna and Bell (1997); to Desmostylia by Domning et al. (1986), Domning (1996), Sepkoski (2002), Domning (2008); to Desmostylia by Cooper et al. (2014); to Paleoparadoxiinae by Barnes (2013), Matsui and Kawabe (2015), Matsui (2017), Matsui et al. (2018); and to Paleoparadoxiidae by Inuzuka (2000), Saegusa (2002), Inuzuka et al. (2006), Domning and Barnes (2007), Hasegawa and Kimura (2008), Beatty (2009), Boessenecker (2011), Hasegawa et al. (2014), Fukuchi and Suzuki (2014), Berta (2017), Domning (2018), Matsui and Tsuihiji (2019), Asai et al. (2025).

Species

P. media, P. tabatai

Synonymy list

Year	Name and author
1959	Paleoparadoxia Reinhart p. 94 figs. Fig. 17
1966	Paleoparadoxia Shikama p. 154
1986	Paleoparadoxia Domning et al. p. 36 figs. Fig. 22
1988	Paleoparadoxia Carroll
1995	Paleoparadoxia Inuzuka et al. p. 524
1996	Paleoparadoxia Domning p. 395
1997	Paleoparadoxia McKenna and Bell p. 375
2000	Paleoparadoxia Inuzuka p. 105
2002	Paleoparadoxia Saegusa p. 4
2002	Paleoparadoxia Sepkoski
2006	Paleoparadoxia Inuzuka et al. p. 3
2007	Paleoparadoxia Domning and Barnes p. 749
2008	Paleoparadoxia Domning p. 643
2008	Paleoparadoxia Hasegawa and Kimura p. 16
2009	Paleoparadoxia Beatty
2011	Paleoparadoxia Boessenecker p. 2
2013	Paleoparadoxia Barnes p. 56
2014	Paleoparadoxia Cooper et al. p. 8 figs. Fig. 3
2014	Paleoparadoxia Fukuchi and Suzuki p. 8
2014	Paleoparadoxia Hasegawa et al. p. 71
2015	Paleoparadoxia Matsui and Kawabe p. 256
2017	Paleoparadoxia Berta p. 171
2017	Paleoparadoxia Matsui p. 4
2018	Paleoparadoxia Domning p. 251
2018	Paleoparadoxia Matsui et al. p. 6
2019	Paleoparadoxia Matsui and Tsuihiji p. 11
2025	Paleoparadoxia Asai et al. p. 8

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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
—	Laurasiatheria
—	Scrotifera
—	Euungulata
—	Panperissodactyla
superorder	Perissodactylamorpha
order	Perissodactyla	()
order	Desmostylia
order	Desmostyloidea	Abel 1933
family	Paleoparadoxiidae	()
genus	Paleoparadoxia

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. †Paleoparadoxia Reinhart 1959

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†Paleoparadoxia media Inuzuka 2005

†Paleoparadoxia tabatai Tokunaga 1939

Diagnosis

Reference	Diagnosis
K. Matsui and S. Kawabe 2015	Emended diagnosis for the genus (humeral characters only).—The greater tubercle extending toward the prox- imal side above the head, a large greater tubercle, a dis- tinct, medially projected lesser tubercle located on the medial side, the intertubercular groove located on the medial side, a shallow and narrow intertubercular groove, an oval head that is slightly convex at the distal end, and absence of the deltoid tuberosity.
K. Matsui et al. 2018	Relatively larger femoral head with respect to the proximal width than Neoparadoxia and Ashoroa; lesser trochanter is bulged to inside; lesser angle of intertrochanteric crest than Behemotops, Neoparadoxia, Ashoroa and Desmostylus; lesser trochanter closer to femoral head than Desmostylus, Cornwallius and Behemotops. For diagnosis of other parts, see [2,34].
Y. Asai et al. 2025	Paleoparadoxia differs from all other desmostylians in possessing the following characters: the zygomatic arch of squamosal inclined to caudally and not broadened dorsoventrally; the coronoid crest of the dentary curved anteriorly. It differs from Neoparadoxia in possessing following characters: the supraorbital process is slightly expanded laterally; the dorsal surface of cranium between supraorbital processes is not depressed; the orbit is positioned slightly dorsally; the mandibular symphysis is slightly rotated anteroventrally.