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I've recently was lucky to have found an online copy of Purdy et al. (2001)'s paper on Lee Creek sharks, and I've found a passage that caught my interest- "In morphology, the teeth lsurus hastalis (Figure 27) are almost identical to those from large individuals (TL=3.7-4.3 m) I. paucus. The tips of the upper anterior teeth of the latter species, however (TL=2.3^1.2 m, n=9), usually lack the labial recurvature that is so well developed in I. hastalis (Figure 28a). In the small number of I. paucus dentitions available to us (n=9), only one dentition (Hubbell collection, JF91980, 2.6 m TL, female) had upper anterior teeth with tips that exhibited a strong labial recurvature. At present, we do not know how common this recurvature is in the extant species. The upper anterior teeth of Leriche's (1910:275-280, figs. 78-86, pi. 16: figs. 16-31) sample of teeth from the Oligocène of Belgium, which he identified as Oxyrhina desori and O. desori flandrica, are identical to those of the extant Isurus paucus. They lack a labial recurvature. This suggests that I. paucus may be a junior synonym of I. hastalis, but because of the small number of dentitions available of I. paucus, we hesitate in synonymizing the two species. " Traditionally, I think people believed that I. paucus evolved from Isurus retroflexus. Capetta (2012) now describes retroflexus in the genus Anotodus as an alopiid with later authors following suit, making it unlikely to have any relation with the longfin mako and making the lineage of paucus unclear. Of the few papers and articles I've read that mention Purdy et al. (2001)'s observation and its possibilities, none give an actual opinion or response to it and simply mention it without anything else, which sort of makes me feel like this observation could be a legitimate possibility. So I really want to know the opinion any of you shark experts and enthusiasts out there on this topic. What do you guys think?