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Rhachiocephalidae

Anomodontia - Cryptodontidae

Taxonomy
Rhachiocephalidae was named by Maisch (2000). It is not extant. It was considered monophyletic by Maisch (2000).

It was reranked as the unranked clade Rhachiocephalidae by Kammerer and Angielczyk (2009).

It was assigned to Pristerodontia by Maisch (2000); and to Cryptodontia by Kammerer and Angielczyk (2009).

Synonyms
Synonymy list
YearName and author
1932Dicynodon tealei Haughton pp. 641-642 fig. 5
2000Rhachiocephalidae Maisch
2009Rhachiocephalidae Kammerer and Angielczyk

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RankNameAuthor
kingdomAnimalia()
Bilateria
EubilateriaAx 1987
Deuterostomia
phylumChordataHaeckel 1874
subphylumVertebrata
superclassGnathostomata
Osteichthyes()
subclassSarcopterygii()
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda
RankNameAuthor
Reptiliomorpha
Anthracosauria
subclassAmphibiosauriaKuhn 1967
Cotylosauria()
Amniota
subclassSynapsida
Therapsida()
orderAnomodontiaOwen 1859
familyCryptodontidae()
Rhachiocephalidae()
Rhachiocephalidae()

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.

Unr. †Rhachiocephalidae Maisch 2000
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G. †Kitchinganomodon Maisch 2002
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Invalid names: Platycyclops acutirostris Broom and George 1950 [synonym], Platycyclops pricei Broom and George 1950 [synonym]
G. †Rhachiocephalus Seeley 1898
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Rhachiocephalus behemoth Maisch 2005
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Invalid names: Dicynodon scheepersi Broom 1948 [synonym], Eocyclops longus Broom 1913 [synonym], Kitchingia planifrons Broom and George 1950 [synonym], Megacyclops rugosus Haughton 1932 [synonym], Megacyclops usiliensis von Huene 1942 [synonym], Megacyclops whaitsi Broom 1931 [synonym], Neomegacyclops cyclops Boonstra 1953 [synonym], Pelanomodon wesselsi Broom 1948 [synonym], Rhachiocephalus angusticeps Broom 1937 [synonym], Rhachiocephalus haughtoni Broom 1932 [synonym]
Invalid names: Dicynodon tealei Haughton 1932 [nomen dubium]
Diagnosis
ReferenceDiagnosis
M. W. Maisch 2000Adult skull lenght exceeds 50 cm, large nasal and prefrontal protuberances, no maxillary tusks or postcanine teeth, wide intertemporal skull roof with narrow exposure of the parietals, very large, rounded nares reaching close to the alveolar margin of the snout, well-ossified to hyperossified braincase with shortened basicranial axis, large bony boss surrounding foramen parietale.
C. F. Kammerer and K. D. Angielczyk 2009As currently defined, Rhachiocephalidae includes only the genera Rhachiocephalus Seeley, 1898, and Kitchinganomodon Maisch, 2002b. The latter taxon has only been ncluded in one phylogenetic analysis (Maisch 2002a). Therefore, in addition to listing autapomorphies from the analyses of Angielczyk (2007), Fröbisch (2007), and Fröbisch & Reisz (2008), we also include autapomorphies identified by Maisch (2002a) in the Appendix. A single autapomorphy of Rhachiocephalidae is recognized in common by Maisch (2002a), Angielczyk (2007), Fröbisch (2007), and Fröbisch & Reisz (2008): (1) parietal foramen surrounded by a strong, often rugose boss. Maisch (2002b, 2003, 2004) provided the most recent diagnoses for Rhachiocephalus, Kitchinganomodon, and Rhachiocephalidae itself. The robust boss surrounding the large, often forward-facing parietal foramen figures prominently in the diagnoses, as does a greater degree of braincase ossification than is typically seen in dicynodonts.