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Taxonomy
Kekenodon was named by Hector (1881) [Sepkoski's age data: T Ol-u Sepkoski's reference number: 1022]. Its type is Kekenodon onamata. It is the type genus of Kekenodontidae.
It was assigned to Basilosauridae by Zittel (1894), Palmer (1904); to Squalodontidae by Hall (1911); to Zeuglodontidae by Lydekker (1892), Trouessart (1898), Stromer (1908), Abel (1914), Abel (1919); to Prozeuglodontidae by Moustafa (1954); to Dorudontidae by Kellogg (1928), Kellogg (1936), Simpson (1945), Keyes (1973), Whitmore and Sanders (1977); to Cetacea by Hector (1881), Sepkoski (2002); to Archaeoceti by Harland et al. (1967), Fordyce (1980), Carroll (1988), Fordyce and Roberts (2009); to Pelagiceti by Martínez-Cáceres et al. (2017); to Kekenodontidae by McKenna and Bell (1997), Fordyce and de Muizon (2001), Uhen (2008), Fitzgerald (2010), Clementz et al. (2014), Uhen (2018); and to Kekenodontidae by Corrie and Fordyce (2022).
It was assigned to Basilosauridae by Zittel (1894), Palmer (1904); to Squalodontidae by Hall (1911); to Zeuglodontidae by Lydekker (1892), Trouessart (1898), Stromer (1908), Abel (1914), Abel (1919); to Prozeuglodontidae by Moustafa (1954); to Dorudontidae by Kellogg (1928), Kellogg (1936), Simpson (1945), Keyes (1973), Whitmore and Sanders (1977); to Cetacea by Hector (1881), Sepkoski (2002); to Archaeoceti by Harland et al. (1967), Fordyce (1980), Carroll (1988), Fordyce and Roberts (2009); to Pelagiceti by Martínez-Cáceres et al. (2017); to Kekenodontidae by McKenna and Bell (1997), Fordyce and de Muizon (2001), Uhen (2008), Fitzgerald (2010), Clementz et al. (2014), Uhen (2018); and to Kekenodontidae by Corrie and Fordyce (2022).
Species
K. onamata (type species)
Synonymy list
| Year | Name and author |
|---|---|
| 1881 | Kekenodon Hector p. 434 |
| 1892 | Kokenodon Lydekker p. 561 |
| 1894 | Kenodon Zittel p. 168 |
| 1898 | Kekenodon Trouessart p. 1010 |
| 1904 | Kekenodon Palmer p. 357 |
| 1908 | Xekenodon Stromer p. 147 |
| 1911 | Kekenodon Hall p. 262 |
| 1914 | Kekenodon Abel p. 220 |
| 1919 | Kekenodon Abel p. 751 |
| 1928 | Kekenodon Kellogg p. 32 figs. Table 1 |
| 1936 | Kekenodon Kellogg p. 226 |
| 1945 | Kekenodon Simpson p. 100 |
| 1954 | Kekenodon Moustafa p. 87 |
| 1967 | Kekenodon Harland et al. p. 774 |
| 1973 | Kekenodon Keyes p. 389 |
| 1977 | Kekenodon Whitmore and Sanders p. 305 |
| 1980 | Kekenodon Fordyce p. iii figs. Table 2 |
| 1988 | Kekenodon Carroll |
| 1997 | Kekenodon McKenna and Bell p. 375 |
| 2001 | Kekenodon Fordyce and de Muizon p. 176 |
| 2002 | Kekenodon Sepkoski |
| 2008 | Kekenodon Uhen p. 445 figs. Table 1 |
| 2009 | Kekenodon Fordyce and Roberts p. 553 |
| 2010 | Kekenodon Fitzgerald p. 370 figs. Table 1 |
| 2014 | Kekenodon Clementz et al. |
| 2017 | Kekenodon Martínez-Cáceres et al. p. 13 |
| 2018 | Kekenodon Uhen p. 79 |
| 2022 | Kekenodon Corrie and Fordyce |
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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.
Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| J. E. Corrie and R. E. Fordyce 2022 | Kekenodon onamata
is a large-sized (8–9 m estimated body length) heterodont archaeocete that differs from archaeocetes basal to the Basilosauridae (Protocetidae, Remingtonocetidae, Ambulocetidae and Pakicetidae) in possessing a prominent lateral tuberosity located lateral to the mallear fossa and posterior cheek teeth with multiple accessory denticles. Kekenodon onamata differs from Basilosauridae in possessing a subrectangular supraorbital process of the frontal that is transversely wider than anteroposteriorly long, diminutive foramina on the dorsal surface of the frontal, prominent lateral tuberosity, mallear fossa positioned more medial to the lateral tuberosity, a medial edge of the anterior process of the periotic and anterior edge of the pars cochlearis forming an obtuse angle, rounded anteromedial angle of the pars cochlearis, pars cochlearis with a hemispherical ventral profile, reduced superior process of the periotic forming a low-lying ridge with distinct anterior and posterior apices, gently concave suprameatal fossa, and lower molariform teeth with accessory denticles on the anterior surface of the crown in place of an re-entrant groove. Kekenodon onamata differs from other Pelagiceti in possessing a protocone remnant in permanent posterior cheek teeth and upper-posterior cheek teeth with a third lingual root. Kekenodon onamata retains archaic features differing from Neoceti including: dorsal and ventral vestibular areas of the internal acoustic meatus separated by an indistinct transverse crest and triple- rooted cheek teeth. Kekenodon onamata differs from Odontoceti in lacking evidence of skull telescoping indicative of echolocation including the posterior and posterolateral expansion and inflation of the maxilla and premaxilla dorsally covering the frontal, and in possessing large and strongly heterodont teeth with postcanines having numerous large and triangular accessory denticles on the anterior and posterior margins of the crown (excluding Inticetus vertizi and Squalodontidae). Kekenodon onamata differs from the taxonomically ambiguous Phococetus vasconum in possessing comparatively larger permanent molariform teeth, crowns of denticulate molariform teeth have a symmetrical profile with a less inclined anterior margin and a more distinct sulcus corresponding to the isthmus joining the anterior and posterior roots. Kekenodon onamata differs from Mysticeti in possessing a pars cochlearis with a longitudinal ventral ridge; from toothed Mysticeti in possessing a larger total body length [excluding Morawanocetinae gen. et. sp. indet. (AMP 9)], a transverse frontomaxillary suture (excluding Aetiocetus polydentatus Barnes et al., 1995), ascending process of maxilla does not extend posterior to the anterior margin of the frontal, an indistinct superior process that forms a low-lying ridge terminating at anterior and posterior apices (excluding Fucaia buelli Marx, Tsai & Fordyce, 2015) and some upper postcanines that are triple-rooted; from the previously recognized toothed mysticetes Llanocetus denticrenatus Mitchell, 1989, Mystacodon selenesis Lambert et al., 2017 and Mammalodontidae in possessing prominent enamel ornament on both the labial and lingual surfaces of the crown; from Llanocetus denticrenatus in possessing accessory denticles on postcanine teeth that are more closely spaced with a profile that is more triangular and less palmate; from Mammalodon colliveri Pritchard, 1939 in possessing apertures for cochlear aqueduct and fenestra rotunda that are not widely separated; from Janjucetus hunderi Fitzgerald, 2006 and Fucaia in lacking an elongate lateral tuberosity that articulates dorsally with the squamosal; from Aetiocetidae in possessing upper and lower double-rooted posterior cheek teeth with roots joined by a transversely narrow isthmus below the crown base, a transversely broader anterior process of the periotic, dorsoventrally straight anterior keel of the anterior process in the periotic and an ovoid pars cochlearis in medial view; from Aetiocetus Emlong, 1966 in possessing distinctly heterodont teeth and double-rooted postcanine teeth; from the previously recognized toothed mysticete Coronodon havensteini Geisler et al., 2017 in possessing a rounded anteromedial corner of the pars cochlearis, postcanine teeth with a more inclined anterior margin of the crown and a primary denticle that is larger than the accessory denticles; from Mystacodon selenesis in having nasals with a posterior margin positioned further anteriorly; from Chaeomysticeti in possessing an orbitotemporal crest located on the posterior edge of the frontal and functional permanent teeth (possibly excluding the eomysticetid Waharoa ruwhenua Boessenecker & Fordyce, 2015); from Fucaia goedertorum (Barnes et al., 1995) and Chaeomysticeti in possessing an anterior process of the periotic with apex dorsal to the ventral edge of the pars cochlearis; from crown Mysticeti in possessing a straight posterior border of frontal, multiple minute foramina on dorsal surface of the frontals, anterior process of the periotic intermediate in length relative to the pars cochlearis, distinct mallear fossa, distinct fovea epitubaria to accommodate the accessory ossicle of the tympanic bulla, periotic lacking a ventrolateral ridge, ovoid proximal opening of facial canal, relatively wide tympanic bulla, distinct medial and lateral lobes of the tympanic bulla open elliptical foramen of the tympanic bulla, tympanic cavity anteroposteriorly divided by transverse ridge and involucral ridge that is nearly straight; from crown Mysticeti and M. colliveri in lacking a pars cochlearis elongated towards the cranial cavity, tubular fundus of the internal acoustic meatus and protruding lateral wall of internal acoustic meatus from the suprameatal fossa; and from crown Mysticeti and J. hunderi in lacking a fenestra rotunda with a fissure oriented towards the perilymphatic foramen and a caudal tympanic process of the periotic with narrow separation from the facial crest of the periotic with a clear separation between the stapedial muscle fossa and facial sulcus. Kekenodon onamata shares with Protocetidae, Mammalodontidae and Coronodon havensteini some upper cheek teeth that are triple-rooted with a third lingual root. Kekenodon onamata shares with Basilosauridae heterodont teeth composed of single- rooted and single-cusped conical crowns and double- rooted cheek with transversely compressed and tall triangular crowns with accessory denticles. Kekenodon onamata shares with Llanocetus denticrenatus a large total body length. Kekenodon onamata shares with Coronodon havensteini a pars cochlearis with a longitudinal ventral ridge and an indistinct superior process that forms a low-lying ridge terminating at anterior and posterior apices. Kekenodon onamata shares with Mammalodontidae and some Odontoceti (including Inticetus vertizi) a median furrow forming a continuous anteroposterior grove on the ventral surface of the tympanic bulla. Kekenodon onamata shares with Mammalodontidae lower posterior cheek teeth roots joined below the crown base by a transversely narrow isthmus. Kekenodon onamata shares with Mammalodon colliveri and some Odontoceti (including eurhinodelphinids) an involucrum possessing a transverse groove on its dorsal surface, which divides it into a narrower anterior section and wider posterior section. Kekenodon onamata shares with Eomysticetidae a poorly-developed superior process of the periotic reduced to a low ridge with anterior and posterior apices. Kekenodon onamata shares with Phococetus vasconum longitudinal ridges ornamenting the basal region of the crown of denticulate teeth. |
Measurements
No measurements are available
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| Source: o = order | |||||
| Reference: Uhen 2004 | |||||
Age range: Duntroonian or 27.30000 to 25.20000 Ma
Collections (3 total)
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Duntroonian | New Zealand (South Island) | K. onamata (45665) | |
| Chattian | New Zealand | K. onamata (225893) | |
| Late/Upper Oligocene | New Zealand | K. sp. (67856) |