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Xenorophus
Taxonomy
Xenorophus was named by Kellogg (1923) [Sepkoski's age data: T Ol-u Sepkoski's reference number: 506]. Its type is Xenorophus sloanii. It was considered monophyletic by Uhen (2008), Uhen et al. (2008).
It was assigned to Agorophiidae by Miller (1923), Kellogg (1928), Hay (1930), Simpson (1945), Keyes (1973), Fordyce (1982); to Autoceta by McKenna and Bell (1997); to Odontoceti by Fordyce and de Muizon (2001); to Cetacea by Sepkoski (2002); to Odontoceti by Kellogg (1923), Harland et al. (1967), Whitmore and Sanders (1977), Fordyce (1981), Carroll (1988), Geisler and Sanders (2003), Uhen (2005), Uhen et al. (2008); and to Xenorophidae by Uhen (2008), Geisler et al. (2011), Geisler et al. (2014), Sanders and Geisler (2015), Godfrey et al. (2016), Marx et al. (2016), Lambert et al. (2017), Berta (2017), Boessenecker and Geisler (2023).
It was assigned to Agorophiidae by Miller (1923), Kellogg (1928), Hay (1930), Simpson (1945), Keyes (1973), Fordyce (1982); to Autoceta by McKenna and Bell (1997); to Odontoceti by Fordyce and de Muizon (2001); to Cetacea by Sepkoski (2002); to Odontoceti by Kellogg (1923), Harland et al. (1967), Whitmore and Sanders (1977), Fordyce (1981), Carroll (1988), Geisler and Sanders (2003), Uhen (2005), Uhen et al. (2008); and to Xenorophidae by Uhen (2008), Geisler et al. (2011), Geisler et al. (2014), Sanders and Geisler (2015), Godfrey et al. (2016), Marx et al. (2016), Lambert et al. (2017), Berta (2017), Boessenecker and Geisler (2023).
Species
X. simplicidens, X. sloanii (type species)
Synonymy list
| Year | Name and author |
|---|---|
| 1923 | Xenorophus Kellogg p. 1 figs. Plates 1-2 |
| 1923 | Xenorophus Miller p. 40 |
| 1928 | Xenorophus Kellogg p. 32 figs. Table 1 |
| 1930 | Xenorophus Hay p. 580 |
| 1945 | Xenorophus Simpson p. 100 |
| 1967 | Xenorophus Harland et al. p. 774 |
| 1973 | Xenorophus Keyes p. 385 |
| 1977 | Xenorophus Whitmore and Sanders p. 305 |
| 1981 | Xenorophus Fordyce p. 1041 |
| 1982 | Xenorophus Fordyce p. 423 |
| 1988 | Xenorophus Carroll |
| 1997 | Xenorophus McKenna and Bell p. 371 |
| 2001 | Xenorophus Fordyce and de Muizon p. 178 |
| 2002 | Xenorophus Sepkoski |
| 2003 | Xenorophus Geisler and Sanders p. 28 |
| 2005 | Xenorophus Uhen p. 1042 |
| 2008 | Xenorophus Uhen p. 435 |
| 2008 | Xenorophus Uhen et al. p. 570 |
| 2011 | Xenorophus Geisler et al. p. 5 figs. Table 1 |
| 2014 | Xenorophus Geisler et al. |
| 2015 | Xenorophus Sanders and Geisler p. 3 |
| 2016 | Xenorophus Godfrey et al. p. 156 |
| 2016 | Xenorophus Marx et al. p. 117 |
| 2017 | Xenorophus Berta p. 160 |
| 2017 | Xenorophus Lambert et al. p. 936 figs. FIgure 14 |
| 2023 | Xenorophus Boessenecker and Geisler p. 11 |
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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
| Reference | Diagnosis | |
|---|---|---|
| M. D. Uhen et al. 2008 | Extraordinary 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 2015 | The 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 2023 | A 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
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| Source: subo = suborder, o = order | |||||
| Reference: Uhen 2004 | |||||