Livro de Resumos - Dinossauros do Maranhão

Paleontologia 231
Cearadactylus atrox (Reptilia, Pterosauria), Santana Group, Araripe Basin,
Northeast Brazil: True or fake?
Bruno Cavalcanti Vila Nova 1,2 & Juliana Manso Sayão 3
Due to their incredible conservation and variety, the Santana Group pterosaurs are subject
of studies for more than 30 years after first reported by Price in 1971. Among the
described species is Cearadactylus atrox. Studied by Leonardi and Borgomanero in 1985,
this pterodactyloid pterosaur has been a source of controversy, being classified in different
suprageneric clades. During the past 24 years, C. atrox was allocated in a monospecific
clade (the Cearadactylidae) by Wellnhofer in 1991 or regarded as closely related to the
Anhangueridae by Kellner in 1996. A rather distinct classification was proposed by Unwin
in 2002, who regarded C. atrox a member of the Ctenochamastidae, a clade that includes
Pterodaustro and Ctenochasma. The main problem with C. atrox is the degree of
preparation of the holotype and only known specimen, which was recently incorporated in
the Museu Nacional (MN-7019-V). The specimen consists of an incomplete skull (missing
only the occipital region) and the lower jaw. After preparation carried out recently, it was
noticed that some of the previously proposed autapomorphies of C. atrox were artifacts
due to the fossilization process or artifacts introduced by local people who tried to make
the fossil more “attractive”. The heterodonty, despite present is not as developed as
previously thought. The premaxillar teeth, for example, were reconstructed by glue and
sediment, and are smaller than supposed, but still larger than the maxillar ones. Also, the
rostral tip of the pre-maxilla, which is narrower than the dentary rostral tip, could be
artificially created because the rostral extremity was broken and glued back, showing the
same substance used in the fake teeth. When this part was glued, it was done inverted,
with the dentary being connected with the premaxilla, and vice-versa. Among the real
characters in the holotype, is can a long ridge in the dentary (before covered by glue and
sediment), (extending to the premaxilla that is a synapomorphy of the genus
Brasileodactylus. A small process in the ventral region of the rostral portion of the
“dentary” can be the vestige of a possible sagittal crest. Furthermore, the skull shows
unfused bones, such as the articular and angular with the dentary, indicating a probable
young to sub-adult individual. The similarities with Brasileodactylus araripensis proposed
by Kellner and Tomida in 2000 are even more noticeable with the preparation. A
preliminary heuristic search with PAUP with the half-prepared fossil nested C. atrox at the
base of Pterodactyloidea, creating a large politomy. Even with the preparation no
completely finished we can conclude that the previous classifications were not fully
correct. Further studies are necessary to clarify this situation.
1 Programa de Pós-graduação em Geociências, Departamento de Geologia, Centro de tecnologia e Geociências,
Universidade Federal de Pernambuco (UFPE), Avenida Acadêmico Hélio Ramos,s/n 0 - Cidade Universitária -
50740-530, Recife, PE. Brasil.
2 Bolsista CAPES.
3 Núcleo de Ciências Biológicas, Centro Acadêmico de Vitória, Universidade Federal de Pernambuco (UFPE), Rua
do Alto Reservatório, s/n 0 - Bela Vista - 55608-680, Vitória de Santo Antão, PE, Brasil.
E-mails: bruno.vilanova@gmail.com, jmsayao@gmail.com
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