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Xenorophus

Mammalia - Cetacea - Xenorophidae

Synonymy list
YearName and author
1923Xenorophus Kellogg p. 1
1923Xenorophus Miller p. 40
1928Xenorophus Kellogg p. 32 figs. Table 1
1930Xenorophus Hay p. 580
1945Xenorophus Simpson p. 100
1967Xenorophus Harland et al. p. 774
1973Xenorophus Keyes p. 385
1977Xenorophus Whitmore and Sanders p. 305
1981Xenorophus Fordyce p. 1041
1982Xenorophus Fordyce p. 423
1988Xenorophus Carroll
1997Xenorophus McKenna and Bell p. 371
2001Xenorophus Fordyce and de Muizon p. 178
2002Xenorophus Sepkoski
2003Xenorophus Geisler and Sanders p. 28
2005Xenorophus Uhen p. 1042
2008Xenorophus Uhen p. 435
2008Xenorophus Uhen et al. p. 570
2011Xenorophus Geisler et al. p. 5 figs. Table 1
2014Xenorophus Geisler et al.
2015Xenorophus Sanders and Geisler p. 3
2016Xenorophus Godfrey et al. p. 156
2016Xenorophus Marx et al. p. 117
2017Xenorophus Berta p. 160
2017Xenorophus Lambert et al. p. 936 figs. FIgure 14
2023Xenorophus Boessenecker and Geisler p. 11

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RankNameAuthor
kingdomAnimalia()
Bilateria
EubilateriaAx 1987
Deuterostomia
phylumChordataHaeckel 1874
subphylumVertebrata
superclassGnathostomata
Osteichthyes()
subclassSarcopterygii()
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda
Reptiliomorpha
Anthracosauria
subclassAmphibiosauriaKuhn 1967
Cotylosauria()
Amniota
subclassSynapsida
Therapsida()
infraorderCynodontia()
Mammaliamorpha
Mammaliaformes
classMammalia
RankNameAuthor
Theriamorpha(Rowe 1993)
Theriiformes()
Trechnotheria
Cladotheria
Zatheria
subclassTribosphenida()
subclassTheria
Eutheria()
Placentalia
Boreoeutheria
Laurasiatheria
Scrotifera
Euungulata
Artiodactylamorpha
Artiodactyla()
Whippomorpha
orderCetacea
Pelagiceti
Neoceti
suborderOdontoceti
familyXenorophidae
genusXenorophus

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. †Xenorophus Kellogg 1923
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Xenorophus simplicidens Boessenecker and Geisler 2023
Xenorophus sloanii Kellogg 1923
Diagnosis
ReferenceDiagnosis
M. D. Uhen et al. 2008Extraordinary widening of the proximal end of the premaxillary, extending outward under the maxilla, and the overspreading of the supraorbital process by the lacrimal, which also sheaths much of the orbit; nasals situated on a level with the postorbital extension of the supraorbital process; nasal passages slope backward; maxilla slopes abruptly downwards in front of the orbit; intertemporal constriction present (Kellogg 1923a, Whitmore and Sanders, 1977).
A. E. Sanders and J. H. Geisler 2015The antorbital process of supraorbital process is formed by the lacrimal and extends posteroventrally under the anterior margin of frontal and into the orbital region. Dorsally, it extends posterolaterally to form a thin layer over the lateral portion of the orbital region of the frontal. Nasal opening situated posterior to the level of the antorbital notches. Nasal bones short and broad, anterior margins on a level with middle of orbit. Ventral exposure of palatal process of premaxilla extends posteriorly to anterior margin of first double-rooted tooth (B3). Palatines exceptionally large, broad anteriorly and narrow posteriorly, and in close contact at the midline. Crown of preserved buccal teeth thick with a prominent cingulum labially and lingually, well-developed accessory cusps anteriorly and pos- teriorly, and moderate-sized roots (Fig. 5). The premaxillary sac region of the premaxilla demonstrates some asymmetry, being 19.1 mm in width on the left side and 16.6 mm on the right.
R. W. Boessenecker and J. H. Geisler 2023A large xenorophid dolphin with adult condylobasal length of 70–75 cm and bizygo- matic width of 26–30 cm, and possessing the following synapomorphies of Xenorophidae, and the xenorophid clade excluding ChM PV 4746: nasal process of premaxilla hypertro- phied, dense, expanded over the supraorbital process of the frontal, forming longitudinal paranaris crest adjacent to nares, and overlain by thin ascending process of maxilla; lacrimal expanded posterodorsally and covering most of anterolateral side of supraorbital process of the frontal; deeply excavated antorbital fossa on the posterior part of the maxilla; maxilla and premaxilla exposed ventrally in a ‘frontal window’ posterior to postorbital ridge; long bladelike lateral tuberosity of periotic; transversely narrow and bladelike anterior process of periotic; tympanic bulla with deep transverse sulcus giving involucrum a stepped dorsal margin; and primitively retaining a sagittal crest, parietals forming most of braincase, and upper and lower embrasure pits.
Xenorophus is characterized by the following features, to the exclusion of other xenorop- hids, unless where noted: palatal process of premaxilla extending posteriorly to level of PC3; rectangular/subrectangular nasals with flat dorsal surface (also shared with Albertocetus); relatively wide rostrum base (43–50% bizygomatic width); rostrum deviated 1.5–4.7◦ to the left; triangular apex of the supraoccipital shield (also shared with Albertocetus); present but low squamosal prominence; absence of a paranaris and postnarial fossae; nasals with a median furrow; rostrum at level of Pc1 wide (~20% of bizygomatic width; narrower in Echovenator and Cotylocara, ~15% BZW); asymmetrical and exceptionally large palatines, broadest anteriorly and tapering posteriorly, with right palatine extending further anteriorly than left (shared with Albertocetus); basioccipital crest bifurcated by a transverse cleft; periotic with thickened superior ridge bearing transverse striations and delimiting a small, deep, circular suprameatal fossa (shared with Albertocetus); proportionally large cheek teeth (5.5–7% of bizygomatic width); 9–10 maxillary teeth (probably 11, but possibly 12 in Cotylocara; 9 in Echovenator); distance between posterior edge of mandibular condyle and posteriormost tooth 1 cm shorter on left than right; and asymmetrical parapophyses and diapophyses on cervical vertebrae.
Measurements
No measurements are available
Composition: hydroxyapatitesubo
Form: roller-shapedo
Ontogeny: modification of partso
Environment: marine, freshwatersubo
Locomotion: actively mobileo
Life habit: aquatico
Depth habitat: surfaceo
Diet: carnivoresubo
Reproduction: viviparoussubo
Created: 2005-03-06 14:21:39
Modified: 2005-09-22 15:42:08
Source: subo = suborder, o = order
Reference: Uhen 2004

Age range: base of the Rupelian to the top of the Chattian or 33.90000 to 23.03000 Ma

Collections (9 total)


Time interval Ma Country or state Original ID and collection number
Rupelian33.9 - 28.1USA (South Carolina) X. sloani (229945) X. sloanii (45500 232432 232433) X. sp. (45777 188100)
Chattian28.1 - 23.03USA (South Carolina) X. simplicidens (229963 232431) X. sp. (112635)