Cearadactylus

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Cearadactylus
Life picture of Cearadactylus atrox [note. 1]

Life picture of Cearadactylus atrox

Temporal occurrence
Lower chalk ; Aptium to Albium
126.3 to 100.5 million years
Locations
Systematics
Archosauria
Ornithodira
Flugsaurier (Pterosauria)
Short-tailed pterosaur (Pterodactyloidea)
Pteranodontoidea
Cearadactylus
Scientific name
Cearadactylus
Leonardi & Borgomanero , 1985
Art
  • Cearadactylus atrox

Cearadactylus is a genus of short-tailed pterosaurs from the Lower Cretaceous of Brazil. Type species and so far the only recognized representative of the monotypic genus is Cearadactylus atrox from the approximately 126 to 100 million year old sedimentary rocks of the Santana Formation (Romualdo Formation) in the Brazilian state of Ceará .

Fossil record

Holotype (MN 7019-V) and so far the only fossil record is an almost completely preserved, 51.5 cm long skull including lower jaw. Only the skull and the occipital region are missing.

Etymology and history of research

The generic name refers to the place where the holotype was found in the Brazilian state of Ceará in combination with the ending " -dactylus ", which is often used by representatives of the pterosaurs , latinized from the ancient Greek δάκτυλος ( dáktylos = "finger"). The additional species “ atrox ” ( Latin “cruel”, “terrible”) refers to both the presumed diet and the noticeably long teeth of the pterosaur.

Cearadactylus atrox was first presented in 1983 at the 8th Brazilian Paleontological Congress. However, since the corresponding conference abstract was missing an illustration, the taxon was initially considered a " nomen nudum ". The actual first description of the genus and type species was made in 1985 by Giuseppe Leonardi and Guido Borgomanero .

The holotype was originally part of the Borgomanero collection under inventory number F-PV-93. The first description was also made under this inventory number. Borgomanero had apparently obtained the fossil from a dealer. The exact location is unknown, but is located on the eastern edge of the Araripe plateau . After Borgomanero's death in 2005, his widow gave the find to the Museu Nacional da Universidade Federal do Rio de Janeiro, where it has since been kept under inventory number MN 7019-V.

In 2009 the fossil was subjected to a post-preparation by Bruno C. Vila Nova , which brought some new findings and made a new description published in 2014 necessary. Among other things, it was found that the fossil had been manipulated unnoticed by the first descriptor. The originally broken tip of the snout had been glued back onto the rest of the skull upside down, so that parts of the premaxilla were in contact with the lower jaw, while the tip of the lower jaw was connected to the upper jaw. In addition, manipulations were found on the teeth in the front jaw area, which made them appear larger than in the original fossil.

features

Despite the manipulations found on the holotype, Cearadactylus atrox is also considered a valid, independent taxon in the new description from 2014. Cearadactylus atrox is described as a medium-sized representative of the Pterodactyloidea. Based on the size of the skull, Leonardi & Borgomanero estimate a wingspan of approx. 4 m.

Vila Nova et al. cite the following features ( autapomorphies ) that occur exclusively in Cearadactylus atrox :

A furrow on the inside of the lower jaw ("dentary groove") extends to the outermost ( rostral ) tip of the bone and is forked at its end. The posterior and ventral edge of the anterior orbital window (fenestra nasoantorbitalis) fused with the external nasal opening (naris externa) form a right angle. The latter feature was already referred to in the first description by Leonardi & Borgomanero, 1985.

The following diagnostically important features are mentioned:

  • The fenestra nasoantorbitalis is large and takes up about 38% of the preserved skull length; a characteristic that is typical for representatives of the Pterodactyloidea.
  • The eye socket and nostril are above the middle of the fenestra nasoantorbitalis.
  • On the back of the premaxilla, the remains of a small, sagittal bone ridge have been preserved. In contrast to representatives of the Annexueridae , however, there are no indications of an analogous bone crest on the lower jaw.
  • The number of teeth is relatively small at 32–36 in the upper jaw and 22–26 in the lower jaw.
  • The dentition is dimorphodontic (consisting of two types of teeth), even if it is less pronounced than assumed on the basis of the original, manipulated holotype. The front teeth are about three times longer and more curved backwards than the rear ones.

Cearadactylus? ligabuei

In 1993 Fabio Marco Dalla Vecchia made another skull of a short-tailed pterosaur from the Santana formation in Brazil provisionally named Cearadactylus? ligabuei described. However, later analyzes showed that Cearadactylus atrox and Cearadactylus? ligabuei do not form a monophyletic group . David Unwin placed the taxon in the genus Appendixuera in 2002 ; Taissa Rodrigues and Alexander Kellner classified Cearadactylus? ligabuei, however, as a sister taxon to Ludodactylus sibbicki , without proposing a new generic name.

Systematics

 Pteranodontoidea  



 Ornithocheiridae  



 Annexueridae  

{{ Expansion depth limit exceeded | 1 = {{ Expansion depth limit exceeded | 1 =  Appendixuera

2 =  Liaoningopterus gui 
                                }}
                             }}


   

 Ludodactylus sibbicki



   

 Brasileodactylus araipensis



   

 Cearadactylus atrox



   

 Guidraco venator


   

 Zhenyuanopterus longiristris


   

 Boreopterus cuiae





   

 Istiodactylidae



   

 Lonchodectes compressirostris



   

 Hongshanopterus lacustris



 Pteranodontidae  

 Pteranodon longiceps


   

 Pteranodon sternbergi




Template: Klade / Maintenance / Style
Systematic position of Cearadactylus atrox within the pteranodontoid , simplified from Upchurch et al., 2015;

The systematic position of Cearadactylus has been the subject of heated discussions since the taxon was first mentioned. Leonardi & Borgomanero had initially identified Cearadactylus atrox as a representative of the Ornithocheiridae , but referred to the species more cautiously in the official first description as a representative of the Pterodactyloidea with an indefinite family membership (" Familia indet. ").

In 1991 Peter Wellnhofer introduced his own family (Cearadactylidae) within the Pterodactyloidea, with Cearadactylus atrox as the only known representative. It is true that Dalla Vecchia followed in 1993 in his description of Cearadactylus? ligabuei this structure, otherwise this proposal was hardly approved by experts.

Kellner & Yukimitsu Tomida identified Cearadactylus atrox 2000 as a representative of the Pteranodontoidea ( sensu Kellner, 1996) and placed the species in a close relationship to the Annexueridae without, however, directly assigning it to this group. Unwin, however, locates the species in 2002 in the group of Gnathosaurinae within the Ctenochasmatoidea .

All these systematic assignments were published before the manipulations on the holotype of Cearadactylus atrox were known. Rodrigues & Kellner, who were already aware of this, confirmed in their phylogenetic analysis in 2013 the position proposed by Kellner & Tomida in 2000 as a sister taxon of the Annexueridae. Vila Nova et al. evaluate Cearadactylus atrox in their new description of the taxon as a representative of the Pteranodontoidea (sensu Kellner, 2003 defined as the smallest clade which includes both Annexuera blittersdorffi and Pteranodon longiceps ) and also see it as a sister taxon of the Annexueridae.

The above cladogram shows the systematic position of Cearadactylus atrox according to Paul Upchurch and co-authors , 2015. According to this phylogenetic analysis, Cearadactylus atrox is a sister taxon of the Annexueridae as a subclade within the Ornithocheiridae. With regard to the phylogenetic structure, however, there is no general consensus and many authors, in the sense of Unwin, 2003, rate the Annexueridae as a junior synonym of the Ornithocheiridae.

Individual evidence

  1. ↑ a b c d e f g h B. C. Vila Nova, JM Sayấo, VHML Neumann & AWA Kellner: Redescription of Cearadactylus atrox (Pterosauria, Pterodactyloidea) from the Early Cretaceous Romualdo Formation (Santana Group) of the Araripe Basin, Brazil. In: Journal of Vertebrate Paleontology , Vol. 34, No. 1, pp. 126-134, 2014. (digitized version )
  2. ↑ a b c d e f G. Leonardi & G. Borgomanero: Cearadactylus atrox nov. gen., nov. sp .: novo Pterosauria (Pterodactyloidea) da Chapada do Araripe, Ceará, Brasil. In: Coletânea de Trabalhos Paleontológicos , Série Geologia, Vol 1, pp. 78–80, 1985. (digitized version )
  3. ^ A b G. Leonardi & G. Borgomanero: Cearadactylus atrox nov. gen., nov. sp .: novo Pterosauria (Pterodactyloidea) da Chapada do Araripe, Ceará, Brasil. In: Ministério de Minas é Energia – DNPM (ed.): Resumos do 8 Congresso Brasileiro de Paleontologia Rio de Janeiro, 1-7 September 1983 , p. 17, 1983.
  4. ↑ a b F. M. Dalla Vecchia: Cearadactylus? ligabuei, nov. sp., a new Early Cretaceous (Aptian) pterosaur from Chapada do Araripe (Northeastern Brazil). In: Bollettino della Societa Paleontologica Italiana , Vol. 32, No. 3, pp. 401-409, 1993. (digitized version )
  5. ↑ a b c A. WA Kellner & Y. Tomida: Description of a new species of Annexueridae (Pterodactyloidea) with comments on the pterosaur fauna from the Santana Formation (Aptian-Albian), northeastern Brazil. In: National Science Museum Monographs, Tokyo , Vol. 17, pp. 1–135, 2000. (digitized version)
  6. ↑ a b c D. M. Unwin: On the systematic relationships of Cearadactylus atrox, an enigmatic Early Cretaceous pterosaur from the Santana Formation of Brazil. In: Messages from the Museum of Natural History in Berlin. Earth science series. Vol. 5, No. 1, pp. 239–263, 2002. ISSN  1435-1943 , doi : 10.1002 / mmng.20020050114 (digitized version )
  7. ^ A b c T. Rodrigues & AWA Kellner: Taxonomic review of the Ornithocheirus complex (Pterosauria) from the Cretaceous of England. In: ZooKeys , Vol. 308, pp. 1-112, 2013. doi : 10.3897 / zookeys.308.5559
  8. ↑ a b P. Upchurch, B. Andres, RJ Butler & PM Barrett: An analysis of pterosaurian biogeography: implications for the evolutionary history and fossil record quality of the first flying vertebrates. In: Historical Biology , Vol. 27, No. 6, pp. 697–717, 2015. (digitized version )
  9. ^ P. Wellnhofer: The Illustrated Encyclopedia of Prehistoric Flying Reptiles. 124 pp., Barnes and Noble Books, 1991.
  10. ↑ AWA Kellner: Pterosaur phylogeny. In: Journal of Vertebrate Paleontology , Vol. 16 (Supplements to No. 3), 45A, 1996.
  11. ↑ AWA Kellner: Pterosaur phylogeny and comments on the evolutionary history of the group. In: E. Buffetaut & JM Mazin (eds.): Evolution and Palaeobiology of Pterosaurs , Geological Society Special Publications 217, pp. 105-137, 2003.
  12. ↑ DM Unwin: On the phylogeny and evolutionary history of pterosaurs. In: E. Buffetaut & J.-M. Mazin (Ed.): Evolution and Palaeobiology of Pterosaurs. Geological Society of London - Special Publications, Vol. 217, pp. 139–190, 2003. (digitized version )

Remarks

  1. ↑ The bone ridge on the lower jaw indicated in the reconstruction shown is not present in Cearadactylus atrox ; the dimorphodontic dentition with significantly longer teeth in the anterior jaw area is not shown.

Web links

Commons : Cearadactylus  - collection of images, videos and audio files