Análisis de los elementos pélvicos y el fémur en titanosaurios en el XX Annual Meeting de la EAVP

Dentro de la línea de investigación de evolución de los distintos módulos del esqueleto apendicular en Titanosauria, miembros del Grupo de Biología Evolutiva de la UNED presentaron la comunicación titulada: “In The Shadow Of The Colossus: Understanding The Pelvic Limb Module Evolution In Titanosauriformes”. En esta contribución se presentaron los resultados obtenidos en el análisis de los elementos pélvicos y el fémur en la línea evolutiva de Titanosauria, inlcuyendo Lohuecotitan pandafilandi. Mediante la cuantificación de la morfología por morfometría geométrica basada en landmark, se puede observar cómo covarían estas estructuras ligadas a la postura y soporte del peso corporal en titanosaurios. Esta metodología además permite observar la señal filogenética de determinados caracteres con interés en la morfología funcional del esqueleto apendicular y la evolución del tamaño hasta las formas de talla mediana del cretácico Ibero-Armoricano o los pequeños Saltasauridae derivados.

The sauropod pelvic and limb skeleton experiences an important change in the Titanosauriformes subclade with the acquisition of wide-gauge posture. It is hypothesized that it is part of the gigantism evolutionary cascade. However, recent studies indicates that the contrary, a phyletic body size reduction may be undergone in the deeply-branched titanosaurians. Such evolutionary changes are still poorly understood by scarcity of pelvic and limb skeletons of titanosaurians and the availability of scanned specimens. In this study the evolution and modularity in the pelvic limb skeleton of Titanosauriformes is approached via 3D-geometric morphometrics. A small sample of pelvic girdle and femoral specimens, representative of the Titanosauriformes lineage (e.g., Euhelopus zdanskyi; e.g., up to Saltasauridae) were digitized via stereophotogrammetry. Landmarks and semilandmark curves were sample via Slicermorph® software and analyzed in R statistical software. For evolutionary analyses we followed current phylogenetic hypotheses, summarized via supertree methodology and trimmed to the current titanosauriformes sample. The results are coherent with previous results that indicate a negate phylogenetic allometric effect and here it is discussed the covariation of the pubic-ischial module and its relationship with the limb musculature and posture in titanosaurian sauropods. Also, here it is discussed the caveats of the scarcity of pelvic sauropod sample as it does not allow to deploy stronger statistical test and its effect on our results.

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Más información:

• Referencia: Páramo, A. 2023. In The Shadow Of The Colossus: Understanding The Pelvic Limb Module Evolution In Titanosauriformes. In: Alba, D.M., Marigó, J., Nacarino-Meneses, C., Villa, A. (Eds.), Book of Abstracts of the 20th Annual Conference of the European Association of Vertebrate Palaeontologists, 26th June– 1st July 2023. Palaeovertebrata, Special Volume 1-2023: 22. DOI: 10.18563/pv.eavp2023 (p. 197).