Veldmeijer Cretaceous, toothed pterosaurs from Brazil. A reappraisal
8. Final remarks
8.1. Ornithocheiridae versus Anhangueridae
The situation on family level is complex (see Veldmeijer et al., submitted), but the acceptance of the crestless, laterally compressed jaws that strongly decrease in width in anterior direction resulting in a sharp pointed beak (figure 8.1) of O. compressirostris as the type species for Ornithocheiridae forces to exclude Brasileodactylus from Ornithocheiridae, as proposed by Unwin (2001) because the morphology contrast distinctly from the expanded and dorsoventrally compressed jaws of Brasileodactylus and indeed from all other known taxa from Brazil (Coloborhynchus, Anhanguera, Criorhynchus, Cearadactylus, Ludodactylus). The acceptance of the mentioned type species contradicts with Unwin’s vision and diagnosis through which he classified Brasileodactylus to Ornithocheiridae. It is interesting to note that Unwin assigned the specimen, in the present work referred to as Cr. simus, as type species of Ornithocheiridae. The diagnosis is, according to Unwin (2001: 204)54: “The first three teeth are relatively large, forming a terminal rosette, and show a marked increase in size posteriorly. The fourth tooth pair is much reduced in size and smaller than the first pair of teeth. Proceeding posteriorly, there is a steady decrease in tooth size up to, typically, the ninth pair, which are of similar basal dimensions to the largest teeth in the terminal rosette. Further posteriorly, tooth size decline again. Consequently, in dorsal view, the rostrum has an expanded anterior tip […]. The expansion of the anterior end of the rostrum is most marked in large species and adult individuals, but may be practically absent in small species and juveniles.” Without going into detail too much, as a detailed discussion of his vision is clearly beyond the scope of this work, few remarks need to be made in light of the systematic palaeontology used here. First, as shown in figure 7.23, the type specimen is a small piece, in which only four alveoli are preserved, mostly badly damaged. So, the description of dentition given by Unwin apparently has been based on other material (not on the type specimen), but he does not mention it: the description fits the dentition of Anhangueridae surprisingly well. Criorhynchus, on the basis of the Munich specimen of Cr. mesembrinus, does not have expanded jaws (in this clearly differs from Anhanguera, Coloborhynchus and Brasileodactylus), no rosette with teeth and does not have a ninth tooth larger than the other ones (this is almost never encountered, see dentition graphs). The non– expanding jaws is a feature that, among others, separates Criorhynchus from the others and is seen in other toothed pterosaurs as well, such as O. compressirostris. In other words, if a character is used in the diagnosis, as Unwin does, specimens not exhibiting this feature should not be classified to this group. Furthermore, explaining differences by means of ontogeny is extremely difficult as there is no way in the scanty pterosaur fossil record to know in most cases what a juvenile and what an adult is (or better ‘not fully–grown’ and ‘fully–grown’). At present, too little is known to be sure on the ontogenetic status (see also Veldmeijer & Signore, 2004).
8.2. The Brasileodactylus–problem
The present work has no intention to give a full pterosaur phylogeny, but rather wants to pinpoint some flaws in the analysis of pterosaurian remains thus far. If we accept the diagnosis for Anhangueridae as presented and discussed in 7.3., Brasileodactylus cannot be assigned to it due to the lack of crests. But clear is that Brasileodactylus shares many features with Coloborhynchus and Anhanguera (anterior expansion of the jaws, dentition pattern, mandibular groove (even though the morphology varies in the various taxa) and post–cranial
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Veldmeijer Cretaceous, toothed pterosaurs from Brazil. A reappraisal characteristics as well), making classification close to Anhangueridae obvious. The type specimen of Ornithocheiridae is crestless as well, but the overall morphology of the jaw differs far more (cf. figure 8.1) from Brasileodactylus. None of the existing models create a satisfying solution (Kellner, 2003; Unwin, 2003). The creation of a new family including the crestless taxa (thus Brasileodactylus, Cearadactylus and also Ludodactylus) which are closely related to the Anhanguerids (closer than to the non–crested Ornithocheirids) seems to be an option. The alternative would be a subfamily, together with the Anhanguerids, within a larger group, based on dental characters. However, as shown above, this would lead to exclusion of Criorhynchus, even though the non–dental morphology clearly shows a close relationship. Until more complete material of especially Brasileodactylus has been published, it seems irresponsible to erect such a group; therefore, reference to classification is marked with ‘?’.
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