Abstract
The increasing numbers of pterosaur finds from Brazil obviously increased our knowledge, but through the years, taxonomy has become less clear as one would expect. Various reasons can be given for this. One is that important morphological features have not been incorporated in the discussion whereas others are, but have
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questionable taxonomic value. Also, sometimes unstated assumptions play an important role on which pterosaurs have been re-classified. It is understandable that one seeks a connection with the pterosaurs from the Cambridge Greensands in England, but this has had a negative impact on the systematics: the fossils from the Cambridge Greensands themselves have been subject to fierce debates and much confusion ever since their first discovery in the latter half of the 19th century.
The present work presents a reappraisal of four closely related taxa with teeth (Anhanguera, Brasileodactylus, Coloborhynchus en Criorhynchus) by means of the study of unpublished and published material in the major collections all around the world, concentrating on cranial parts. In chapter 2, a largely complete skeleton of Coloborhynchus is described. The specimen has been classified as new species. Chapter 3 presents various post-cranial elements, on the basis of which it is concluded that interspecific differences in the post-cranial skeleton are so small that an evaluation is necessary. More important for the present work, however, is the description of the mandible of Criorhynchus, which confirms the strong deviating dentition pattern relative to the other taxa. Chapter 4 presents one of the most complete mandibles of Anhanguera. The study of this specimen resulted among others in the discovery of an important diagnostic morphological feature of the mandible. The next chapter (chapter 5) is a preliminary description of a largely unprepared skull and wing of a fossil in the collection of the AMNH, New York. The specimen is tentatively classified as Brasileodactylus mainly because of the crestless jaws (currently, the fossil is completely prepared and under study). In chapter 6, an almost complete mandible of Brasileodactylus is described. Furthermore, post-cranial material as well as a small piece of maxilla, belonging to the same individual of Brasileodactylus is presented. This is the first description of post-cranial material of this genus; as expected, there is a high degree of conformity with the other taxa. Chapter 7 summarises and shortly discusses all taxa, presents the main conclusions again, and furthermore, presents the measurements of the dentition, showing specific patterns for each taxon. The final remarks in chapter 8 offer a discussion on the problems with the Cambridge Greensands (Ornithocheiridae versus Anhangueridae).
This study resulted in the refinement of various diagnoses and makes the distinction between the four taxa clearer: animals with a premaxillary and dentary sagittal crest (Coloborhynchus, Criorhynchus and Anhanguera) belong to Anhangueridae; the crestless Brasileodactylus however, cannot be classified to Anhangueridae, despite the close relationship due to the incompleteness of its remains. The diagnosis of Ornithocheiridae, as recently proposed in a re-evaluation, is not based on the type specimen and the used specimen does not show the described characters.
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