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New Triassic pterosaurs: Arcticodactylus, Austriadraco, Bergamodactylus + pterosaur reproduction (free pdfs)



Ben Creisler
bcreisler@gmail.com

Long before there were fireworks in the sky, there were pterosaurs...
Two new papers in open access:



Kellner, Alexander W.A. (2015)
Comments on Triassic pterosaurs with discussion about ontogeny and
description of new taxa.
Anais da Academia Brasileira de Ciências  87(2): 669-689
doi:  http://dx.doi.org/10.1590/0001-3765201520150307.
http://www.scielo.br/scielo.php?script=sci_pdf&pid=S0001-37652015000200669&lng=en&nrm=iso&tlng=en
http://www.scielo.br/pdf/aabc/v87n2/0001-3765-aabc-87-02-00669.pdf

Eudimorphodon ranzii was the first Triassic pterosaur to be described
and several specimens have been referred to this taxon mainly based on
the presence of multicuspid teeth. Since this dental feature has been
observed in several other pterosaurs, the revision of some specimens
assigned to Eudimorphodon shows that they represent new taxa as
follows: Arcticodactylus cromptonellus (comb. nov.), Austriadraco
dallavecchiai (gen. et sp. nov.) and Bergamodactylus wildi (gen. et
sp. nov.). A preliminary analysis of pterosaur ontogeny resulted in
the recognition of six distinct ontogenetic stages (OS1-6). According
to this classification, the holotype of Arcticodactylus cromptonellus
has reached OS2, and although being ontogenetically much younger than
others, the conspicuous anatomical differences lead to its exclusion
from Eudimorphodon. The holotypes of Austriadraco dallavecchiai,
Bergamodactylus wildi and Carniadactylus rosenfeldi have reached at
least OS5, which demonstrates that the anatomical differences among
them cannot be explained by ontogeny. Moreover, Bergamodactylus wildi
reaches about 60% of the maximized wingspan of Carniadactylus
rosenfeldi and further concurs that these specimens collected in
distinct Triassic Islands of Europe are not conspecific. The present
study increases the diversity of Triassic flying reptiles and further
pushes the origins of this clade back to at least the Middle Triassic.


===

WANG, XIAOLIN; KELLNER, ALEXANDER W. A.; CHENG, XIN; JIANG, SHUNXING;
WANG, QIANG; SAYÃO, JULIANA M.; RODRIGUES, TAISSA; COSTA, FABIANA R.;
LI, NING; MENG, XI; ZHOU, ZHONGHE (2015)
Eggshell and Histology Provide Insight on the Life History of a
Pterosaur with Two Functional Ovaries.
Anais da Academia Brasileira de Ciências (advance online publication)
doi:  http://dx.doi.org/10.1590/0001-3765201520150364
http://www.scielo.br/scielo.php?script=sci_abstract&pid=S0001-37652015005050364&lng=en&nrm=iso&tlng=en
http://www.scielo.br/pdf/aabc/2015nahead/0001-3765-aabc-201520150364.pdf


The counterpart of a previously described non-pterodactyloid pterosaur
with an egg revealed the presence of a second egg inside the body
cavity of this gravid female. It clearly shows that pterosaurs had two
functional oviducts and demonstrates that the reduction of one oviduct
was not a prerequisite for developing powered flight, at least in this
group. Compositional analysis of one egg suggests the lack of a hard
external layer of calcium carbonate. Histological sections of one
femur lack medullary bone and further demonstrate that this pterosaur
reached reproductive maturity before skeletal maturity. This study
shows that pterosaurs laid eggs even smaller than previously thought
and had a reproductive strategy more similar to basal reptiles than to
birds. Whether pterosaurs were highly precocial or needed parental
care is still open to debate.