José Luis Barco

Discriminating between Medium-Sized Tridactyl Trackmakers: Tracking Ornithopod Tracks in the Base of the Cretaceous (Berriasian, Spain)

Background Recent work on the Jurassic-Cretaceous transition of the Iberian Range (Spain) has opened a new window onto the interpretation of the trackmakers of some medium-sized tridactyl tracks. The ichnotaxon Therangospodus oncalensis has been described in the Huérteles Formation (Berriasian) and is one of the classical tracks from the area assigned to medium-sized theropods. Methodology/Principal Findings A review of the type locality of Therangospodus oncalensis (Fuentesalvo tracksite) and other tracksites from the Huérteles Formation (Berriasian) has yielded new information on the morphology, gait and trackmaker identity of the aforementioned ichnospecies. The new data suggest that the trackmaker is an ornithopod rather than a theropod on the basis of the length/width ratio, the anterior triangle length-width ratio, the short steps, the round to quadrangular heel pad impression and the probable manus impressions. Conclusions/Significance T. oncalensis shows similarities with various tracks from the Berriasian of Europe assigned to Iguanodontipus. The ichnotaxonomical status of this ichnospecies is here considered as Iguanodontipus? oncalensis due to the current state of knowledge of the ichnotaxonomy of medium-sized ornithopod tracks. This reassessment of I? oncalensis also has two significant implications for the palaeoecology of the faunas during the deposition of the Huérteles Formation: 1- the high number and percentage of theropod tracks would be lower than previous papers have suggested. 2- the gregarious behaviour described in the type locality (Fuentesalvo) would be among ornithopods instead of theropods.

Intra-trackway morphological variations due to substrate consistency: the El Frontal dinosaur tracksite (lower Cretaceous, Spain).

An ichnological and sedimentological study of the El Frontal dinosaur tracksite (Early Cretaceous, Cameros basin, Soria, Spain) highlights the pronounced intra-trackway variation found in track morphologies of four theropod trackways. Photogrammetric 3D digital models revealed various and distinct intra-trackway morphotypes, which reflect changes in footprint parameters such as the pace length, the track length, depth, and height of displacement rims. Sedimentological analyses suggest that the original substrate was non-homogenous due to lateral changes in adjoining microfacies. Multidata analyses indicate that morphological differences in these deep and shallow tracks represent a part of a continuum of track morphologies and geometries produced by a gradient of substrate consistencies across the site. This implies that the large range of track morphologies at this site resulted from similar trackmakers crossing variable facies. The trackways at the El Frontal site present an exemplary case of how track morphology, and consequently potential ichnotaxa, can vary, even when produced by a single trackmaker.

New Data on Therangospodus oncalensis from the Berriasian Fuentesalvo Tracksite (Villar del Río, Soria, Spain): An Example of Gregarious Behaviour in Theropod Dinosaurs

Therangospodus oncalensis is a Berriasian theropod ichnotaxon from the Cameros Basin (Soria Province, Spain). We discovered new trackways assigned to this ichnotaxon during cleaning and conservation works at the type locality (Fuentesalvo), enabling us to describe it more precisely. Therangospodus oncalensis was made by a medium-sized theropod dinosaur and is characterized by a single tapering pad on each toe, a rounded heel impression and a narrow trackway. In addition to having similar morphometric characteristics, most of the trackways at the Fuentesalvo site show comparable size and biometric features. This indicates that, in terms of size and age, a homogeneous population of a single theropod species could have produced these tracks. Moreover, the similar orientation (lying within a range of only 15°) and estimated speed suggested by most of the trackways, lend weight to the hypothesis that the trackmaker of Therangospodus oncalensis was able, at least at times, to move in structured packs displaying gregarious behaviour. Furthermore, this is the first structured pack of theropods to be described.

On the validity of Pteraichnus palacieisaenzi, Pascual Arribas and Sanz Pérez 2000: new data from the Huérteles formation

Abstract The original definition of the ichnospecies Pteraichnus palacieisaenzi Pascual Arribas and Sanz Pérez (Estudios Geológicos 56:73–100, 2000) failed to comply with some of the norms proposed in the most recent version of the ICZN (International code of zoological nomenclature, fourth edition 1999) for the definition of new taxa. This was an undesired consequence of the long process of its publication. Furthermore, the progressive growth of lichens in the tracksite made it difficult to see the tracks, as a result of which some authors have called the validity of P. palacieisaenzi into question. After being completely cleaned, the tracks are of a better quality than at the time of their discovery, making it possible to describe the characters of the ichnotaxon in greater detail. Moulds of the type specimens have been prepared with a view to housing them in a public institution (Museo Numantino, Soria). The present paper redescribes the ichnospecies P. palacieisaenzi and compares this ichnotaxon with other tracks from a variety of pterosaur ichnospecies. Finally, a hypothesis is proposed on the trackmaker of the ichnospecies.KurzfassungDie ursprüngliche Definition der Ichnospezies Pteraichnus palacieisaenzi Pascual Arribas & Sanz Pérez 2000 verletzte einige Regeln für die Definition neuer Taxa, die in der aktuellen Ausgabe des Internationalen Codes für Zoologische Nomenklatur (ICZN 1999) dargelegt wurden. Dabei handelte es sich um eine unerwünschte Folge des langen Veröffentlichungsvorgangs. Ferner war es infolge des fortschreitenden Flechtenwachstums in den Spurenfossilien an der Stätte schwierig, die Spuren selbst auszumachen, was dazu geführt hat, dass einige Autoren die Gültigkeit der Ichnospezies P. palacieisaenzi in Frage gestellt haben. Nach einer vollständigen Reinigung sind die Ichnofossilien von besserer Qualität als zu dem Zeitpunkt ihrer Entdeckung, was es uns ermöglicht hat, die Charaktere des Ichnotaxons ausführlicher zu beschreiben. Es sind Abgüsse der Typ-Exemplare erstellt worden, um sie in einer öffentlichen Einrichtung (Museo Numantino, Soria) zu deponieren. In dieser Arbeit wird die Ichnospezies Pteraichnus palacieisaenzi neu beschrieben und mit verschiedenen anderen Flugsaurier-Ichnospezies verglichen. Zum Schluss wird eine Hypothese über den Autor dieser Ichnospezies dargelegt.

First record of stegosaur dinosaur tracks in the Lower Cretaceous (Berriasian) of Europe (Oncala group, Soria, Spain)

ABSTRACT This paper describes for the first time a stegosaur track from the Cretaceous of Europe. It focuses on a cast that preserves pes-manus tracks recovered in the Huérteles Alloformation of the Berriasian of Soria (northern Spain). This track has been assigned to Deltapodus isp. on the basis of the pes morphology. Nonetheless, in the manus lacks the claw-shaped imprint of the pollex that characterizes Deltapodus brodricki Whyte & Romano, 1994, the type ichnospecies of the ichnogenus Deltapodus Whyte & Romano, 1994. The stegosaurs were abundant and diverse in the Late Jurassic of the Iberian Peninsula, as evidenced by their ichnological and osseous record. The presence of Deltapodus isp. provides further support for the view that the stegosaurs did not disappear in the Jurassic-Cretaceous boundary crisis and kept going on the Iberian Peninsula for at least for the initial part of the Early Cretaceous.

A Palaeoichnological Itinerary Through the Cenozoic of the Southern Margin of the Pyrenees and the Northern Ebro Basin (Aragón, Northeast Spain)

This work aims to bring to light the great wealth of mammal and avian tracksites of the Cenozoic of the southern margin of the Pyrenees and the northern Ebro Basin (Aragon, northeast Spain) by designing a palaeoichnological itinerary that includes the main tracksites. Scientific research in these fields is currently being carried out with very interesting preliminary results, given the poor ichnofossil record in the Palaeogene worldwide. In addition to its scientific importance, however, we want to emphasize the value of this palaeontological heritage as a tourist and educational resource and also the geoconservation work carried out on the tracksites. In some of these sites (Fondota, Sierra de Luna and La Playa Fósil), conservation and adaptation activities have been undertaken over the last few decades. These activities have allowed people to access and visit these tracksites, thus promoting them as socioeconomic assets of this region.