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Xenorophidae

Mammalia - Cetacea - Xenorophidae

Taxonomy
Xenorophidae was named by Uhen (2008) [Xenorophidae was used by Luo & Gingerich (1999) and Marino et al (2004) with no diagnosis; Xenorophiidae was used by Fordyce (2003) and Bianucci and Landini (2007) with no diagnosis.]. It was considered monophyletic by Uhen (2008) and Sanders and Geisler (2015).

It was assigned to Odontoceti by Sanders and Geisler (2015) and Churchill et al. (2016); and to Odontoceti by Uhen (2008), Rice (2009), Geisler et al. (2011), Geisler et al. (2014), Marx et al. (2016), Boessenecker et al. (2017) and Berta (2017).

Synonymy list
YearName and author
2008Xenorophidae Uhen p. 434
2009Xenorophidae Rice p. 235 figs. Table 1
2011Xenorophidae Geisler et al. p. 5 figs. Table 1
2014Xenorophidae Geisler et al.
2015Xenorophidae Sanders and Geisler p. 2
2016Xenorophidae Churchill et al. p. 1
2016Xenorophidae Marx et al. p. 115
2017Xenorophidae Berta p. 160
2017Xenorophidae Boessenecker et al. p. 4

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RankNameAuthor
kingdomAnimalia()
Triploblastica
Nephrozoa
Deuterostomia
phylumChordataHaeckel 1847
subphylumVertebrata
superclassGnathostomata
Osteichthyes()
Sarcopterygii
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda
Reptiliomorpha
Anthracosauria
Batrachosauria()
Cotylosauria()
RankNameAuthor
Amniota
Synapsida()
Therapsida()
infraorderCynodontia()
Epicynodontia
infraorderEucynodontia
Probainognathia
Mammaliamorpha
Mammaliaformes
classMammalia
orderCetacea
Pelagiceti
Neoceti
suborderOdontoceti
familyXenorophidae
familyXenorophidae

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.

Diagnosis
ReferenceDiagnosis
M. D. Uhen 2008Geisler & Sanders (2003) list the following synapomorphies: base of the rostrum transversely narrow (compared to the width of the skull across the orbits), maxillae wedged between palatines, anterior edge of the supraorbital process directed anterolaterally, maxilla and palatine and/or pterygoid form ventromedial edge of internal infraorbital foramen, lateral tuberosity of petrosal (periotic) elongate and narrow separation of crista parotica and caudal tympanic pro- cess of petrosal (periotic). In addition to these characteristics, both Xenorophus and Albertocetus (new genus, named below) have greatly expanded lacrimals. In both genera, the lacrimal forms the anterior border of the orbit and extends posteriorly, dorsally covering the frontal over most of the lateral margin of the supraorbital process of the frontal. Archaeodelphis has a somewhat enlarged lacrimal, but not nearly as enlarged as in Xenorophus and Albertocetus.
A. E. Sanders and J. H. Geisler 2015The only known clade of cetaceans in which the premaxilla—instead of the maxilla—articulates with the frontal along most of its entire anteroposterior extent and extends laterally across the medial half of the supraorbital pro- cess of the frontal beneath the maxilla (Fig. 3A). The premaxilla bears a prominent crest that is lateral to the nasal opening and nasal bone and that is overlain by a thin layer of the maxilla on its lateral side; the lacrimal covers most of the dorsal surface of the lateral portion of the supraorbital process of the frontal; the maxilla is deeply excavated adjacent to the antorbital notch, forming an ovoid basin to which we here apply the term antorbi- tal fossa (Fig. 3A). Formerly this structure had been referred to as the rostral basin (Geisler and Sanders, 2003), but we here introduce a new term to indicate the differences in morphology between these depressions in ziphiids and xenorophids. Ven- trally, the maxilla and/or premaxilla is visible through a broad circular opening—here termed the ‘frontal window’—in the supraorbital portion of the frontal bone. The frontal window is visible in the holotype of X. sloanii (Fig. 3C), although the ante- rior margin of the window is damaged and the posterior margin is not preserved. Although the facial and orbital parts of the skull are highly telescoped, the parietals in xenorophids form most of the dorsal and lateral portions of the braincase as in typical land mammals, and there is a sagittal crest (Whitmore and Sanders, 1977:fig. 1; Uhen, 2008:fig. 2).
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 Late/Upper Oligocene to the top of the Chattian or 28.40000 to 23.03000 Ma

Collections (12 total)


Time interval Ma Country or state Original ID and collection number
Rupelian33.9 - 28.1USA (South Carolina) Albertocetus meffordorum (189779) Albertocetus sp. (206951) Inermorostrum xenops (186670) Xenorophus sloanii (45500) Xenorophus sp. (45777) Xenorophus sp., Albertocetus meffordorum (188100)
Late/Upper Oligocene28.4 - 23.03USA (North Carolina) Albertocetus meffordorum, Echovenator sp. (71651)
Chattian28.1 - 23.03USA (North Carolina) Xenorophidae indet., Albertocetus meffordorum (54075)
Chattian28.1 - 23.03USA (South Carolina) Archaeodelphis patrius (68974) Cotylocara macei (154905) Echovenator sandersi (180866) Xenorophus sp. (112635)