PBDB Taxon

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Cynthiacetus

Mammalia - Cetacea - Basilosauridae

Taxonomy

Cynthiacetus was named by Uhen (2005). It was considered monophyletic by Uhen (2008).

It was synonymized subjectively with Pontogeneus by Gingerich (2015).

It was assigned to Dorudontinae by Uhen (2005), McLeod and Barnes (2008), Uhen (2008), Uhen (2009), Schouten (2011) and Gao and Ni (2015); and to Basilosauridae by Martinez-Cáceres and Muizon (2011), Uhen (2013), Marx et al. (2016), Martínez-Cáceres et al. (2017), Berta (2017) and Uhen (2018).

Species

C. maxwelli, C. peruvianus

Synonymy list

Year	Name and author
2005	Cynthiacetus Uhen p. 159 figs. 1-7
2008	Cynthiacetus McLeod and Barnes p. 94
2008	Cynthiacetus Uhen p. 561
2009	Cynthiacetus Uhen p. 93
2011	Cynthiacetus Martinez-Cáceres and Muizon
2011	Cynthiacetus Schouten p. 18
2013	Cynthiacetus Uhen p. 9 figs. Figure 6
2015	Cynthiacetus Gao and Ni p. 156 figs. Table 1
2016	Cynthiacetus Marx et al. p. 101
2017	Cynthiacetus Berta p. 159
2017	Cynthiacetus Martínez-Cáceres et al. p. 11
2018	Cynthiacetus Uhen

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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
—	Cladotheria
—	Zatheria
subclass	Tribosphenida	()
subclass	Theria
—	Eutheria	()
—	Placentalia
—	Boreoeutheria
—	Laurasiatheria
—	Scrotifera
—	Euungulata
—	Artiodactylamorpha
—	Artiodactyla	()
—	Whippomorpha
order	Cetacea
—	Pelagiceti
family	Basilosauridae
genus	Cynthiacetus

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. †Cynthiacetus Uhen 2005

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†Cynthiacetus maxwelli Uhen 2005

†Cynthiacetus peruvianus Martinez-Cáceres and Muizon 2011

Diagnosis

Reference	Diagnosis
M. D. Uhen 2005	Large body size distinguishes Cynthiacetus from other dorudontines. Skull, cervical vertebrae, and anterior thoracic vertebrae are similarin morphology to those of Basilosaurus. The posterior thoracic vertebrae, lumbar vertebrae, and anterior caudal vertebrae are not elongate, but have proportions similar to other dorudontines, distinguishing Cynthiacetus from Basilosaurus.
M. D. Uhen 2008	Skull, cervical vertebrae, and anterior thoracic vertebrae are similar in size and morphology to those of Basilosaurus, distinguishing Cynthiacetus from other dorudontines. The posterior thoracic vertebrae, lumbar vertebrae, and anterior caudal vertebrae are not elongate, but have proportions similar to other dorudontines, distinguishing Cynthiacetus from Basilosaurus.
M. Martinez-Cáceres and C. Muizon 2011	Large basilosaurid lacking vertebral elongation observed in Basilosaurus; skulls lightly shorter than Basilosaurus and significantly longer than all other dorudontines (e.g., Dorudon, Zygorhiza, Saghacetus). Cynthiacetus differs from all other basilosaurids in: nasal strongly tapering anteriorly in both species (even more than in Dorudon); atlas with a high, massive and dome-shaped neural arch; vertebrarterial foramina on the cervical vertebrae significantly larger; absence of the ventral expansion of the transverse processes in cervical vertebrae. The supraoccipital shield of Cynthiacetus proportionally wider than that in Saghacetus; nuchal crest posterodorsally oriented (anterodorsally in Zygorhiza).
M. D. Uhen 2013	Large basilosaurid lacking elongation of the posterior thoracic, lumbar and anterior caudal vertebrae seen in Basilosaurus; skull similar in size, but slightly shorter than Basilosaurus and much longer than all other basilosaurids. Cynthiacetus differs from all other basilosaurids in: nasal strongly tapering anteriorly; atlas with a high, massive and dome-shaped neural arch; verte- brarterial foramina on the cervical vertebrae significantly larger; absence of the ventral expansion of the transverse processes in cervical vertebrae. The supraoccipital shield of Cynthiacetus proportionally wider than that seen in Saghacetus (after Martínez-Cáceres and de Muizon, 2011).