INVESTIGADORES
DÍAZ MARTÍNEZ Ignacio
congresos y reuniones científicas
Título:
Alternating Pes Morphologies In A Long Ornithopod (Dinosauria) Trackway
Autor/es:
NOVELLA RAZZOLINI; BERNAT VILA; IGNACIO DÍAZ MARTÍNEZ; FÉLIX PÉREZ-LORENTE; PHILLIP L MANNING; ANGEL GALOBART
Lugar:
Al Jadida
Reunión:
Congreso; First International Congress on Continental Ichnology; 2015
Resumen:
Symmetry is the fundamental condition in a normal gait, thus irregularities in consecutive steps can be linked to an asymmetric gait pattern in which an abnormal condition is affecting locomotor ability (i.e. hip, hind limb or foot injury, pathology or congenital deformation). Long biped (or facultative quadruped) trackways are the best examples to observe and quantify variation in both limb dynamics and track morphologies. In the late 90s, two research teams recorded variation between pes pace lengths of a long ornithopod trackway from the El Barranco de La Canal tracksite (Lower Cretaceous, Western Cameros basin, La Rioja, Spain). In this study of the same tracksite, using LiDAR imaging and photogrammetric techniques, it was possible to quantitatively and qualitatively reevaluate the long trackway.In addition to the alternating pes pace lengths, we also observed qualitative differences between the right and the left tracks concerning the disposition of the lateral digits II-IV with respect to the central digit III. These differences were quantified through the usual interdigital angle (IDA) and the interdigital width (IDW) parameters. The latter (IDW) measures the separation between the medial/lateral edges of digit III and medial/lateral edges of digits II/IV. Results show a 10% difference between the left-right (short) and right-left (long) consecutive steps, suggesting a weak limping behaviour. Furthermore, right and left tracks have identical values for interdigital angles (32º) and interdigital widths (0.2) recorded in the tracks external half (digits III and IV), while significantly differ in interdigital angles (right: 5º; left: 18º) and interdigital widths (right: 0.2; left: - 0.2) of the tracks medial halfs (digits II and III). Given that the substrate is homogenous (a very fine grained sandstone), the consistent repetition of these parameters is here suggested to be linked to an anatomical origin and more precisely, an injury or pathology on the left digit II. However, the abnormal condition present in the left pes digit II did not significantly impair the trackmaker?s locomotor ability, due to the low percentage of the discrepancy of the lengths of the consecutive steps.