6.12.16

Laminación vertebral de un nuevo ejemplar de titanosaurio de Lo Hueco en la 76th Annual Meeting de la SVP


Los dinosaurios saurópodos de Lo Hueco también estuvieron en el 76th Annual Meeting de la Society of Vertebrate Paleontology que tuvieron lugar en Salt Lake City (Utah). Los titanosaurios de Lo Hueco empiezan a ser habituales en los congresos paleontológicos que frecuentamos. Cuando no hablamos de histología, hablamos de morfometria... Sin embargo, en Salt Lake City, hemos decidido dedicar un póster entero para explicar el patrón de laminas en una secuencia de vertebras dorsales articuladas. Este ejemplar de Lo Hueco nos posibilita describir la variabilidad morfológica asociada al esqueleto axial en dinosaurios titanosaurios. Este trabajo contó con la participación de investigadores del Grupo de Biología Evolutiva UNED, Natural History Museum of Los Angeles County, Universidad Autónoma de Madrid, Facultad de Bellas Artes de la UCM y Museum für Naturkunde.

The Lo Hueco site (Campanian-Maastrichtian. Cuenca, Spain) has provided several partial titanosaurian skeletons in articulation or with a low dispersion, producing a unique record in Europe. HUE-EC-11 is a partially articulated specimen preserving a series of anterior-middle dorsals in articulation, several appendicular bones and osteoderms in possible association. Only a few European titanosaurs preserve relatively complete dorsal series, and HUE-EC-11 provides important information about the morphological changes related with laminae patterns, pneumaticity, the hyposphene-hypantrum articulation and neural spine. The anatomical observed changes are mainly related to the morphology of the transverse process and the neural spine. The diapophysis migrates to a more anterior position than the parapophysis. In the anteriormost dorsals, the transverse processes are transversely long, reducing their length by half in the middle dorsals. A drastic change in the neural spine orientation and morphology is observed in the transition between anterior and middle dorsals. The neural spine of the anteriormost dorsals bears a pronounced posterior inclination (< 40º), and becomes vertical and latter anteriorly projected. A similar transition is observed in Dreadnoughtus. The lamination is relatively simple and, as far as available, no important secondary lamination is present. The diapophyseal laminae complex is composed by the pcdl, acpl, pcpl (present inthe middle dorsals, and joins to the acpl dorsally before reaching the parapophysis), and prdl. The neural spine bears well-developed spol, spdl (with an accessory spdl), prsl and posl. This titanosaur features the presence of a hyposphene-hypantrum articulation composed of a short hyposphenic crest, which appears in the middle dorsals. HUE-EC-11 shares with several titanosaurs a dorsally facing diapophysis: the absence of sprl in the anterior and middle dorsals; or the absence of the podl. The vertical orientation of the neural spines is also shared with several titanosaurs, like Isisaurus and Diamantinasaurus. The presence of a hyposphenic crest is common in basal titanosaurs and in some European titanosaurs, as Ampelosaurus and the dwarf form Magyarosaurus. The phylogenetic context of the Lo Hueco titanosaurs is uncertain, and therefore their relationship with aeolosaurine and saltasaurid lineages is still unknown. Furthermore, a preliminary analysis of the axial remains suggests the presence of at least two, but maybe three, different vertebral morphotypes in the site.
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