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Two open access articles on dinosaur tracks in Journal of Iberian Geology

Journal of Iberian Geology, 40(1). Special Issue: Palaeodiversity and
palaeoecology of Iberian ecosystems. New insights into the
Phanaerozoic biotas from Spain and Portugal (guest editors: M. Furio,
C. Martinez-Perez & A. Santos-Cubedo). Date of online publication,
25th February 2014.


Castanera, D., B. Vila, N.L. Razzolini, V.F. Santos, C. Pascual & J.I.
Canudo. 2014. Sauropod trackways of the Iberian Peninsula:
palaeoetological and palaeoenvironmental implications. Journal of
Iberian Geology, 40(1): 49-59.

Abstract: More than a hundred sauropod tracksites, ranging in age from
Middle Jurassic (Bathonian) to Late Cretaceous (Maastrichtian), are
repor­ted from the Iberian Peninsula (Spain and Portugal). Sauropod
trackway orientation patterns throughout an entire geographic area
such as the Iberian Peninsula and over different time periods may
provide new data about the palaeoecology and behavioural patterns of
sauropods. The studied tracksites exhibit two main trackway
orientation patterns, directional and random, indicating different
behaviours in grega­rious or solitary (milling) individuals.
Gregarious behavioural patterns are mainly observed within
Parabrontopodus/Breviparopus-like and Brontopodus-like ichnotypes of a
single size class (either small or medium-sized), indicating age
segregation. Among the gregarious sauropods the former ichnotype is
linked with inland environments, while the latter is mainly linked
with coastal environments. Solitary trackways are mainly of
medium-sized to large individuals, are also linked with both inland
(Parabrontopodus/Breviparopus-like) and coastal environments
(Parabrontopodus/Breviparopus-like, Brontopodus-like), and belong to
the above-mentioned ichnotypes as well as to Polyonyx-like ichnotypes.
Thus, no obvious link between gregarious behaviour and the
palaeoenvironmental setting can be inferred from the sauropod track
record of the Iberian Peninsula. Nonetheless, sauropod trackways
showing titanosauriform characters (Brontopodus-like) are more common
in coastal environments, contrary to what might be expected given this
group’s apparent taxonomic preference for inland environments.

Keywords: Sauropod trackways, palaeoecology, gregarious behaviour,
Jurassic, Cretaceous, Iberian Peninsula.

Garcia-Ortiz, E. & F. Perez-Lorente. 2014. Palaeoecological inferences
about dinosaur gregarious behaviour based on the study of tracksites
from La Rioja area in the Cameros Basin (Lower Cretaceous, Spain).
Journal of Iberian Geology, 40(1): 113-127.

Abstract: In La Rioja the widespread ichnological record of dinosaurs
ranges from the Berriasian to the Aptian age (Early Cretaceous).
There, due to the high palaeodiversity, several evidences of
gregarious behaviour can be observed in different types of footprints
(sauropods, theropods and ornithopods). Moreover, due to the huge
dimensions of some sites, different types of dinosaur tracks
representing gregarious behaviour can be found very close in space and
time. All these evidences have been compiled and analysed, obtaining
an overview of this type of behaviour in relation to the type of
trackmaker. Twenty-eight evidences of gregariousness have been found,
of which nine are of sauropod footprints, twelve of theropod, seven of
ornithopod, and one of unknown bipedal dinosaurs. These data have been
further divided into accumulations and sets of parallel trackways. In
sauropod footprints the main evidence is represented by the
accumulations of tracks made by herds of individuals of the same size.
In ornithopod footprints there are accumulations and parallel
trackways of large size individuals and even family groups. In
theropod footprints, sets of parallel trackways of few individuals of
the same size (from small to medium) are the most common evidence and
there are no data about gregariousness in large theropod footprints.
Thus, data were obtained on different sizes of herds, size of
individuals and structure of the groups depending on different
ichnotypes, providing information about important palaeoecological
aspects of their trackmakers, such as population structure.

Keywords: dinosaurs, footprints, gregarious behaviour, Cretaceous, La
Rioja, Spain.

Jose Ignacio Ruiz-Omenaca
Museo del Jurasico de Asturias (MUJA)
E-33328 Colunga, Spain