Las colas de los titanosaurios de Lo Hueco en el 77th Annual Meeting de la SVP

Desde su descubrimiento en 2007, hace diez años, el yacimiento de Lo Hueco ha aportado una ingente cantidad de material sobre los vertebrados fósiles de finales del Cretácico. Los saurópodos titanosaurios son especialmente abundantes y diversos en el yacimiento, y el estudio de su variabilidad cada vez arroja más luz sobre su aspecto y relaciones de parentesco.

Un estudio preliminar sobre la diversidad funcional de las colas de estos dinosaurios ha sido presentado en el 77 congreso de la Society of Vertebrate Paleontology. Aquí tenéis el resumen del trabajo presentado:

Lo Hueco is an Upper Cretaceous (Campanian-Maastrichtian) macro-vertebrate fossil site, where more than fourteen partially articulated and/or associated titanosaur sauropod specimens have been found. So far, only Lohuecotitan pandafilandi and a braincase tentatively referred to cf. Ampelosaurus sp., have been identified. The presence of several articulated titanosaur caudal series and the usage of 3D modelling is a unique opportunity for morphofunctional and biomechanical analyses.
The preliminary description of six proximal-middle caudal series (with totally fused neurocentral sutures) suggests the presence of four different morphotypes. Morphotype I has short, anteriorly curved neural spines, high pedicels, and dorsally inclined prezygapophyses. Morphotype II has longer and posteriorly inclined neural spines; short pedicels; slender, long and horizontal prezygapophyses and postero-distally curved anterior chevrons. Morphotype III has short, anteroposteriorly expanded distal end of the neural spines, high pedicels, horizontal and short prezygapophyses and straight chevrons.
Finally, the tail of Lohuecotitan does not belong to the abovementioned morphotypes, as it has straight and perpendicular anterior neural spines, anteroposteriorly short pedicels, horizontal prezygapophyses and straight chevrons.
Considering the neural spines orientation, which corresponds to the resultant force of the individual forces exerted by muscles and ligaments, Morphotype I would have had a stronger posterior force acting upon the spine, Morphotype II would have had a stronger anterior force acting upon the spine and Morphotypes III and Lohuecotitan would have had the anterior and posterior forces at balance. The further the pre-postzygapophyseal contact gets from the articulation of centra, the smaller the range of motion is, so Morphotypes I and III would have had more restricted ventriflexion than morphotypes II and Lohuecotitan. The distally curved chevrons of Morphotype II imply a smaller relative attachment area for the caudofemoral musculature compared with the straight chevrons of Morphotype III and Lohuecotitan.
This preliminar analysis suggests the titanosaurs from Lo Hueco had very different forces acting upon their caudal vertebrae, ranges of motion and muscular surface insertions. Future analyses will help to evaluate the relation among different type of motions and body plans, as well as their taxonomical significance.

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Más información:

• Vidal, D., Sanz, J., Mocho, P., Páramo, A., Escaso, F., Marcos, F., Ortega, F. 2017. The titanosaur tails from Lo Hueco (Cuenca, Spain): Four different ways to shake?. 77th Annual Meeting of SVP. Abstract book. 208.