. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. TOOTH-BEARING MAXILLA OF LYCORHINUS ANGUSTIDENS 373 bear patches of striations indicating direction of bite. These striations are helpful to understanding the bite, which is seen to have a posteriad component. It is important to note that the striations have the same orientation as the ridge on tooth 10 discussed below. That such striations are rare suggests a degree of imprecision in the bite such that occluding surfaces are continuously roughly pol- ished. Teeth 9 and 10 have heels worn into the ba
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. TOOTH-BEARING MAXILLA OF LYCORHINUS ANGUSTIDENS 373 bear patches of striations indicating direction of bite. These striations are helpful to understanding the bite, which is seen to have a posteriad component. It is important to note that the striations have the same orientation as the ridge on tooth 10 discussed below. That such striations are rare suggests a degree of imprecision in the bite such that occluding surfaces are continuously roughly pol- ished. Teeth 9 and 10 have heels worn into the base of their facets. The present interpretation of 10 and 11 differs from Hopson's but is made with the benefit of the hindsight afforded by the new maxilla. Tooth 10 has a raised ridge between facets, such as would result if the edges of occluding uppers did not quite meet. The preserved portion of the 11th tooth was clearly part of a perfectly normal full-sized tooth; it is faceted and is raised labiad of 10, and it was thus opposed by the successor to the tooth responsible for the posterior facet on 10. It is suggested that the differences in wear facet orientation that Hopson (1980) recorded (supposedly increasingly horizontal with age) are illusory, as witness the continuity of facets on 7 with those of its neighbours. Indeed tooth 4 seem- ingly has the most nearly horizontal wear facets, but is less worn than tooth 5, which apparently has more oblique facets. This specimen represents a mature animal of a species characterized by very oblique wear facets. Three more teeth could have been present in the living dentary (see Fig. 3). This dentition contains ample evidence of a staggered occlusal arrangement between upper and lower teeth. In Figure 2 vertical lines above teeth indicate where upper teeth would meet each other. Some of the most interesting and instructive lower teeth are those that at first sight apparently do not conform to this staggered pattern. The best place
Size: 2736px × 914px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
