Osteichthyes - Dicynodontia - Lystrosauridae

"Owen (1859) initially described this taxon as the type species of a new genus, Ptychognathus, named for dicynodonts with anteroposteriorly short skulls with tall, strongly deflected snouts. In subsequent papers Owen variously treated Ptychognathus as a distinct genus (e.g. Owen, 1876) or a subgenus of Dicynodon (e.g., Owen, 1860). Although P. declivis was the first named species of Lystrosaurus, it was not combined in that genus until work by Brink (1951), who recognized the validity of the species over L. latirostris (Owen, 1860), which was previously in wide use for the exceptionally tall-snouted species of Lystrosaurus (Cluver 1971; Colbert, 1974; Grine et al., 2006) have all recognized the validity of L. declivis" from Kammerer et al., 2011.

Synonyms: Dicynodon (Ptychognathus) declivis Owen 1860 [objective synonym], Dicynodon (Ptychognathus) latirostris Owen 1860, Lystrosaurus primitivus Toerien 1954, Lystrosaurus wagneri Van Hoepen 1916, Ptychognathus alfredi Owen 1862, Ptychognathus declivis Owen 1860 [objective synonym], Ptychognathus depressus Owen 1876, Ptychosiagum declivis Lydekker 1890 [objective synonym]

Full reference: A. S. Brink. 1951. On the genus Lystrosaurus Cope. Transactions of the Royal Society of South Africa 33(1):107-120

Belongs to Lystrosaurus according to R. Broom 1932

See also Brink 1951, Cluver 1971, Colbert 1974, Georgi 2006, King 1988, Kitching 1977, Lydekker 1890, Owen 1860, Owen 1860, Owen 1862, Toerien 1954 and Van Hoepen 1916

Sister taxa: Dicynodon seeleyi, Lystrosaurus broomi, Lystrosaurus curvatus, Lystrosaurus georgi, Lystrosaurus hedini, Lystrosaurus maccaigi, Lystrosaurus murrayi, Lystrosaurus robustus, Lystrosaurus shichanggouensis, Lystrosaurus weidenreichi, Lystrosaurus youngi, Prolystrosaurus strigops

Type specimens:

• Lystrosaurus declivis: NHMUK 36221, a skull. Its type locality is Rhenosterberg (Lystrosaurus Assemblage Zone), which is in an Induan terrestrial siliciclastic in the Katberg Formation of South Africa.
• Dicynodon (Ptychognathus) declivis: NHMUK 36221, a skull.
• Dicynodon (Ptychognathus) latirostris: NHMUK 36222, a skull. Its type locality is Rhenosterberg (Lystrosaurus Assemblage Zone), which is in an Induan terrestrial siliciclastic in the Katberg Formation of South Africa.
• Lystrosaurus primitivus: Its type locality is Farm Ripplemead, New Bethesda, which is in a Triassic terrestrial horizon in the Balfour Formation of South Africa.
• Lystrosaurus wagneri: TM 28. Its type locality is Harrismith Commonage, which is in an Induan/Olenekian terrestrial horizon in the Normandien Formation of South Africa.
• Ptychognathus alfredi: NHMUK 47342, a partial skull. Its type locality is Rhenosterberg (Lystrosaurus Assemblage Zone), which is in an Induan terrestrial siliciclastic in the Katberg Formation of South Africa.
• Ptychognathus declivis: NHMUK 36221, a skull.
• Ptychognathus depressus:
• Ptychosiagum declivis:

Ecology: herbivore

Distribution:

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Specimen images are retrieved through the ePANDDA API.