Orientation and characteristics of theropod trackways from the Las Losas Palaeoichnological site (La Rioja. Spain)
- Romero-Molina, M.M. 2
- Sarjeant, W.A.S. 5
- Pérez-Lorente, F. 4
- López, Antonio. 3
- Requeta, E. 1
- 1 Fundación Patrimonio Paleon., Enciso, Spain
- 2 Instituto de Estudios Riojanos, Muro de la Mata 8, Logroño, E-26071, Spain
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3
Universidad de Granada
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4
Universidad de La Rioja
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5
University of Saskatchewan
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ISSN: 1042-0940
Año de publicación: 2003
Volumen: 10
Número: 2
Páginas: 241-254
Tipo: Artículo
Otras publicaciones en: Ichnos
Resumen
The Las Losas site (approximately 500 m 2) was cleared in July 1998 and revealed 375 theropod dinosaur footprints. Statistical surveys of their biomorphical and morphometrical data are congruent with a continuous morphological transition among the theropod footprints-a transition which does not allow us to differentiate ichnogroups. Certain footprints show a longitudinal groove in their toes. The foot movement of their trackmakers can be inferred from these grooves. There are also, in this outcrop, i) trackways whose ichnites are either regular or anomalous according to the position of crossing, ii) semiplantigrade trackways with digitigrade sections and iii) trackways that cross the footprint site without variation in their footprints. These facts allow us to infer that: i) the substrate hardness was different in different zones at particular moments, and ii) the variation in the regularity and shape of the footprints depended upon the mud conditions at the moment they were made. Three preferential directions of march are shown by the trackways, suggesting different phases of activity.