. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 242 ANNALS OF THE SOUTH AFRICAN MUSEUM while lateral compression generally results in folding back of the posterior squamosal flanges. Analysis of imperfections such as these will usually indicate the nature of distortion suffered by a particular skull, and allow a tentative reconstruction of the original shape to be made. However, in this study use was made as far as possible only of skulls which were either uncrushed or had undergone easily interpreted distortion. The sphenethmoid complex was regar
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 242 ANNALS OF THE SOUTH AFRICAN MUSEUM while lateral compression generally results in folding back of the posterior squamosal flanges. Analysis of imperfections such as these will usually indicate the nature of distortion suffered by a particular skull, and allow a tentative reconstruction of the original shape to be made. However, in this study use was made as far as possible only of skulls which were either uncrushed or had undergone easily interpreted distortion. The sphenethmoid complex was regarded as the main indicator of distortion, and in all cases of doubt the presphenoid and orbito- sphenoid were exposed in order to determine their relative positions. THE SPECIES OF LYSTROSAURUS Lystrosaurus curvatus (Owen) (Figs 27, 36, 37, 66, 67) Dicynodon curvatus Owen, 1876. Lystrosaurus curvatus Broom, 1932. Lystrosaurus wageri, jorisseni & theileri Van Hoepen, 1916. Type specimen: Locality: Cradock, Morphologically, this species appears to be the closest to the Permian dicynodonts. The snout, while typically lystrosaurian, is not as far ventrally produced as in some species of Lystrosaurus, and frontonasal and premaxillary ridges and frontal bosses are absent. Among dicynodonts these latter features appear to be confined to some of the more specialized species of Lystrosaurus. The skull roof is smooth and the premaxillary plane curves over in a smooth arc to meet the frontoparietal plane. Although a transverse frontonasal ridge as such is absent, slight indications of a fold on the prefrontal may be present. POF. Fig. 66. Lystrosaurus curvatus, Nat. Mus. No. Skull in lateral. 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 South African Museum. Cape Town : The Museum
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
