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Platecarpus planifrons

Reptilia - Mosasauridae

Taxonomy
Clidastes planifrons was named by Cope (1874). Its type specimen is AMNH 1491, a partial skeleton, and it is a 3D body fossil. Its type locality is 7 miles southeast of Castle Rock, which is in a Coniacian/Santonian marine chalk in the Niobrara Formation of Kansas.

It was recombined as Platecarpus planifrons by Williston (1898), Hay (1930), Konishi and Caldwell (2007), Bell et al. (2013) and Fanti et al. (2014); it was recombined as Lestosaurus planifrons by Hay (1902); it was considered a nomen vanum by Russell (1967); it was recombined as Plesioplatecarpus planifrons by Konishi and Caldwell (2011) and Driscoll et al. (2019).

Synonymy list
YearName and author
1874Clidastes planifrons Cope p. 31
1875Clidastes planifrons Cope p. 135
1898Platecarpus planifrons Williston p. 188
1902Lestosaurus planifrons Hay p. 470
1930Platecarpus planifrons Hay p. 260
2007Platecarpus planifrons Konishi and Caldwell
2011Plesioplatecarpus planifrons Konishi and Caldwell p. 777
2013Platecarpus planifrons Bell Jr. et al. p. 576
2014Platecarpus planifrons Fanti et al.
2019Plesioplatecarpus planifrons Driscoll et al.

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RankNameAuthor
kingdomAnimalia()
Bilateria
EubilateriaAx 1987
Deuterostomia
phylumChordataHaeckel 1874
subphylumVertebrata
superclassGnathostomata
Osteichthyes()
subclassSarcopterygii()
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda
Reptiliomorpha
RankNameAuthor
Anthracosauria
subclassAmphibiosauriaKuhn 1967
Cotylosauria()
Amniota
Sauropsida
classReptilia
Squamata()
familyMosasauridae
Russellosaurina(Bell 1997)
subfamilyPlioplatecarpinae(Dollo 1884)
Plioplatecarpini()
genusPlatecarpus
speciesplanifrons()

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.

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Diagnosis
ReferenceDiagnosis
T. Konishi and M. W. Caldwell 2007Thin, elongate septomaxillae forming floor of posterior half of narial chamber; prefrontal and postorbitofrontal not contacting above orbit; dorsal surface of frontal planar, no supraorbital bulge; dorsal median keel of frontal absent; frontal preorbital width greater than interorbital width; frontal with paired posteromedian flanges; parietal foramen enclosed within parietal table; parietal table short; 10 to 15 pterygoid teeth; anterodorsal border of quadrate with distinct posterior notch; distal end of suprastapedial process tapering medially; stapedial pit narrow, keyhole shaped; thin, well-defined vertical crest on medial face of quadrate shaft; retroarticular process drawn out posterolaterally.
T. Konishi and M. W. Caldwell 2011"Thin, elongate septomaxillae forming floor of posterior half of narial chamber; prefrontal and postorbitofrontal not contacting above orbit; dorsal frontal surface planar, lacking supraorbital bulge; median dorsal bulge or weak keel present anteriorly on frontal; frontal preorbital width greater than interorbital width; frontal supraorbital border thickened; frontal with paired posteromedian flanges; frontal lacking paired posterolateral flanges; parietal foramen completely enclosed within parietal table; 10 to 15 pterygoid teeth; anterodorsal border of quadrate with distinct posterior notching; distal end of suprastapedial process lacking conspicuous expansion, tapering medially; stapedial pit narrow, keyhole-shaped; thin, well-defined vertical crest on medial face of quadrate shaft; coronoid process posterior border meeting surangular dorsal border at right angle; retroarticular process drawn out posteromedially; seventh rib articulating with sternum; 11 long ribs participating in forming rib cage; posterior-most rib forming rib cage not distinctly longer than posteriorly adjacent one, latter measuring approximately 70% of former in length; scapula blade hardly protruding anterior to condyle; scapula smaller than coracoid; distal end of ulna wider than proximal end. As for other diagnostic characters, refer to those of Konishi et al. (2010) for Platecarpus, which at the time included Plesioplatecarpus planifrons."
Measurements
No measurements are available
Composition: phosphaticsubp
Environment: terrestrialuc
Locomotion: actively mobilec
Life habit: aquaticf
Diet: carnivoref
Vision: well-developedf
Reproduction: ovoviviparousf
Created: 2018-01-05 16:32:54
Modified: 2018-01-05 16:32:54
Source: f = family, c = class, subp = subphylum, uc = unranked clade
References: Carroll 1988, Gervais 1852, Hendy et al. 2009

Age range: Santonian or 86.30000 to 83.60000 Ma

Collections (5 total)


Time interval Ma Country or state Original ID and collection number
Late/Upper Coniacian - Early/Lower Santonian89.3 - 83.5USA (Kansas) Clidastes planifrons (type locality: 123571) Platecarpus planifrons (123572 123574)
Late/Upper Coniacian - Early/Lower Santonian89.3 - 83.5USA (Texas) Platecarpus planifrons (151422)
Santonian86.3 - 83.6USA (Kansas) Platecarpus planifrons (99385)