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New dinosaur papers in Anais da Academia Brasileira de Ciencias

From: Ben Creisler

In case the advance online papers have not been mentioned 
(Note that the complete texts are available in English 
but can't be downloaded yet in pdf form.)

Gallina, Pablo A.  (2011)
Notes on the axial skeleton of the titanosaur Bonitasaura 
salgadoi (Dinosauria-Sauropoda)
Anais da Academia Brasileira de Ciencias
ahead of print Epub Feb 04, 2011
doi: 10.1590/S0001-37652011005000001  


Notes on the axial skeleton of the titanosaur Bonitasaura 
salgadoi (Dinosauria-Sauropoda)
Sauropod axial anatomy is particularly important in 
understanding morphological features and phylogenetic 
analyses. Spatial arrangement of zygapophyses and rib 
articulations, as well as their complex laminar 
development, help to recognize the relative position of 
isolated vertebral elements. The presence of anterior, 
mid and posterior elements along the cervical, dorsal and 
caudal series in Bonitasaura salgadoi allows the analysis 
of several anatomical characteristics. These include the 
pattern of neurocentral closure with unfused, partially 
fused and completely fused elements in a peculiar 
temporal sequence, as well as several neural spine 
modifications and the laminar arrangement. The variations 
in neural spine morphology include a lateral expansion of 
the distal tip in cervico-dorsal region, different 
lateral constituents of these lateral expansions, and a 
marked deviation in spine angulation. The spinal 
inclination allows the division into three easily 
recognizable vertebral regions separated by two 
landmarks, which adds support in the determination of an 
accurate vertebral position for isolated elements. 
Finally, an analysis of the vertebral laminae reveals the 
importance of examining vertebral series in order to 
recognize laminar homologies and developmental series. 
Two vertebral laminae are analyzed here.

González Riga, Bernardo J. (2011) 
Speeds and stance of titanosaur sauropods: analysis of 
Titanopodus tracks from the Late Cretaceous of Mendoza, 
Anais da Academia Brasileira de Ciencias [online]. ahead 
of print, pp. 0-0.  Epub Feb 04, 2011. ISSN 0001-3765.  
doi: 10.1590/S0001-37652011005000002.


Speed estimations from trackways of Titanopodus 
mendozensis González Riga and Calvo provide information 
about the locomotion of titanosaurian sauropods that 
lived in South America during the Late Cretaceous. 
Titanopodus ichnites were found at Agua del Choique, a 
newly discovered track site in the Loncoche Formation, 
Late Campanian-Early Maastrichtian of Mendoza, Argentina. 
This speed study follows the hypothesis of dynamic 
similarity proposed by Alexander. As a refinement of this 
method, a complementary equation is presented here based 
on an articulated titanosaurian specimen collected in 
strata that are regarded as correlative to those that 
have yielded Titanopodus tracks (Allen Formation, Neuquén 
Basin). This analysis indicates that hip height can be 
estimated as 4.586 times the length of the pes track in 
derived titanosaurs. With an estimation of the hip height 
and the stride measurements, the speed is calculated. The 
study of two wide-gauge trackways indicates that 
Titanopodus ichnites were produced by mediumsized 
titanosaurs (hip height of 211-229 cm) that walked at 4.7-
4.9 km/h towards the south and southwest, following, in 
part, a sinuous pathway. These speeds and some taphonomic 
features of tracks (prominent rims, distorted elongated 
shapes)indicate the capacity of derived titanosaurs for 
walking effectively over a very wet and slippery 
substrate. In the ichnological record, the walking speeds 
of Titanopodus trackmakers are somewhat faster than those 
previously inferred for most sauropods.

Grillo, Orlando N.  and  Azevedo, Sergio A.K. (2011). 
Recovering missing data: estimating position and size of 
caudal vertebrae in Staurikosaurus pricei Colbert, 1970. 
Anais da Academia Brasileira de Ciencias [online]. ahead 
of print, pp. 0-0.  Epub Feb 04, 2011. 
ISSN 0001-3765.  doi: 10.1590/S0001-37652011005000003.


Missing data is a common problem in paleontology. It 
makes it difficult to reconstruct extinct taxa accurately 
and restrains the inclusion of some taxa on comparative 
and biomechanical studies. Particularly, estimating the 
position of vertebrae on incomplete series is often non-
empirical and does not allow precise estimation of 
missing parts. In this work we present a method for 
calculating the position of preserved middle sequences of 
caudal vertebrae in the saurischian dinosaur 
Staurikosaurus pricei, based on the length and height of 
preserved anterior and posterior caudal vertebral centra. 
Regression equations were used to estimate these 
dimensions for middle vertebrae and, consequently, to 
assess the position of the preserved middle sequences. It 
also allowed estimating these dimensions for non-
preserved vertebrae. Results indicate that the preserved 
caudal vertebrae of Staurikosaurus may correspond to 
positions 1-3, 5, 7, 14-19/15-20, 24-25/25-26, and 29-47, 
and that at least 25 vertebrae had transverse processes. 
Total length of the tail was estimated in 134 cm and 
total body length was 220-225 cm.