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Amphidelphis

Osteichthyes - Cetacea

Taxonomy

Synonymy list
YearName and author
2025Amphidelphis Lambert et al. p. 388

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RankNameAuthor
kingdomAnimalia()
Bilateria
EubilateriaAx 1987
Deuterostomia
phylumChordataHaeckel 1874
subphylumVertebrata
superclassGnathostomata
classOsteichthyes
subclassSarcopterygii()
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda
Reptiliomorpha
Anthracosauria
subclassAmphibiosauriaKuhn 1967
Cotylosauria()
Amniota
subclassSynapsida
Therapsida()
infraorderCynodontia()
Mammaliamorpha
RankNameAuthor
Mammaliaformes
classMammalia
Cladotheria
Zatheria
subclassTribosphenida()
subclassTheria
Eutheria()
Placentalia
Boreoeutheria
Laurasiatheria
Scrotifera
Euungulata
Artiodactylamorpha
Artiodactyla()
Whippomorpha
orderCetacea
Pelagiceti
Neoceti
suborderOdontoceti
genusAmphidelphis

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. †Amphidelphis Lambert et al. 2025
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Diagnosis
ReferenceDiagnosis
O. Lambert et al. 2025The differential diagnosis focuses primarily on differ-
ences with taxa that were found to be closely related to Amphidelphis
in our phylogenetic analysis and comparison (other members of
the Chilcacetus clade, Eoplatanistidae, Eurhinodelphinidae, and
Squaloziphiidae). Amphidelphis bakersfieldensis n. comb. is a small
(bizygomatic width estimated at 174 mm in the holotype), longi-
rostrine, and homodont dolphin species differing from Argyrocetus
patagonicus in its smaller size, in the rostrum being proportionally
considerably shorter (ratio between preorbital width and rostrum
length estimated at 0.5), and lacking an extended premaxillary
portion, in the dorsal opening of the mesorostral groove being
narrower than the premaxilla at rostrum base, in the premaxillary
foramen being roughly at the level of the antorbital notch, and in
the absence of ankylosis for the symphysis of the mandibles; from
‘Argyrocetus’ joaquinensis in its smaller size, in the dorsal opening
of the mesorostral groove being narrower than the premaxilla at
rostrum base, in the presence of more than one dorsal infraorbital
foramen at rostrum base, in the proportionally shorter and wider
nasals, and in the nasals partly overhanging the bony nares; from
Chilcacetus in its smaller size, in the rostrum being proportionally
shorter, in possessing a deep sulcus anterior to the main dorsal in-
fraorbital foramen at rostrum base, and in the palatines not being
separated anteromedially for a long distance at rostrum base; from
Perditicetus in its smaller size, in the premaxillary foramen being
roughly at the level of the antorbital notch, and in the zygomatic
process of the squamosal being dorsoventrally more slender; from
Caolodelphis in its smaller size, the frontals not being separated
anteromedially on the vertex, and the basioccipital crests being
transversely thinner; from Macrodelphinus in its much smaller
size, in the rostrum being proportionally shorter and lacking an
extended premaxillary portion, in the premaxillary foramen being
roughly at the level of the antorbital notch, and in the exposure of
the frontals on the vertex being shorter and narrower.
It differs from Crisocetus, Dolgopolis, Squaloziphius, and Yaquinace-
tus in the postglenoid process of the squamosal being significantly
shorter anteroposteriorly, and from Dolgopolis, Squaloziphius, and
Yaquinacetus in the dorsal opening of the mesorostral groove be-
ing more gradual anterior to the bony nares. It differs from most
members of other longirostrine to hyper-longirostrine homodont
extinct families (including Eoplatanistidae and Eurhinodelphinidae)
in the absence of a deep lateral groove along most of the rostrum
and in the absence of ankylosis for the symphysis of the mandibles.
It further differs from Eurhinodelphinidae in lacking an extended edentulous anterior premaxillary portion of the rostrum and in the
nasals partly overhanging the bony nares. It further differs from Eo-
platanistidae in the premaxillary foramen being roughly at the level
of the antorbital notch, in the thinner and flatter antorbital process,
in the acute anterior margin of the nasal partly overhanging the
bony nares, and in the less anteriorly projected supraoccipital shield.