. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. CRANIAL MORPHOLOGY OF THE DICYNODONT GENUS LTSTROSAURUS 245. Fig. 69. Lystrosaurus platyceps. No. 706. Skull in dorsal Lystrosaurus, they have retained the smooth, gently rounded skull roof which is characteristic of Permian dicynodonts. They comprise group B on p. 237. In the following species of Lystrosaurus there is a departure from this con- dition and the skulls are characterized by the presence of certain pronounced bosses and ridges on the snout and skull roof. These species comprise gr
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. CRANIAL MORPHOLOGY OF THE DICYNODONT GENUS LTSTROSAURUS 245. Fig. 69. Lystrosaurus platyceps. No. 706. Skull in dorsal Lystrosaurus, they have retained the smooth, gently rounded skull roof which is characteristic of Permian dicynodonts. They comprise group B on p. 237. In the following species of Lystrosaurus there is a departure from this con- dition and the skulls are characterized by the presence of certain pronounced bosses and ridges on the snout and skull roof. These species comprise group A on p. 237. Lystrosaurus oviceps Haughton (Figs 70, 71) Lystrosaurus oviceps Haughton, 1915. Lystrosaurus breyeri Van Hoepen, 1916. Type specimen: 641. Locality: Tarka River, Cradock District. L. oviceps may be regarded as the most primitive of those species which possess transverse frontonasal ridges and frontal bosses. It is the only species in this group in which the facial surface of the premaxilla is not flat, and the smoothly curved snout, sloping back to the frontonasal ridge, is reminiscent of L. curvatus. The snout is, however, very strongly developed and bears a prominent median longitudinal ridge. Since the snout and skull roof merge smoothly into each other, the frontonasal ridge does not divide the facial from the frontal plane. Two frontal tuberosities are present. The frontonasal suture is mainly transverse, and the frontals do not project forward between the pre- frontals and nasals, but a short median process formed by both frontals pro- trudes forward for a short way between the nasals. This type of frontonasal suture resembles that of some specimens of L. curvatus. The type skull has undergone considerable crushing, and the occiput is. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original w
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
