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DISCUSSION

Apart from Varanus, the only potential fossil African relation of YPM 57012 is Pachyvaranus crassispondylus Arambourg, 1952, a problematic but probably platynotan species from the terminal Cretaceous of Morocco (Molnar, 2004). This taxon, known only from vertebrae, is distinguished by pachyostosis that markedly restricts the neural canal and by certain histological features (de Buffrénil et al., 2007) and lacks zygosphene–zygantral articulations and precondylar constriction (pers. obs. on MSUVP 1343). Moreover, its surface texture is dominated by tiny pores rather than clear striae. Thus, P. crassispondylus has autapomorphies that YPM 57012 lacks and lacks apomorphies that YPM 57012 possesses (discussed in full below), and there is no reason at present to consider the two to be related. In constrast, several morphological considerations suggest that the species represented by YPM 57012 is …