El esqueleto apendicular de Spinophorosaurus en el XVI Annual Meeting de la EAVP

Los dinosaurios saurópodos representaron un volumen importante de los trabajos presentados por los integrantes del Grupo de Biología Evolutiva de la UNED en el reciente XVI Annual Meeting de la European Association of Vertebrate Paleontologists (EAVP) que ha tenido lugar en la ciudad de Lisboa. Una de estas comunicaciones proponía describir nueva información sobre el esqueleto apendicular de Spinophorosaurus nigerensis, un saurópodo encontrado en el Jurásico Medio de Niger y se titulaba "New information about the appendicular skeleton of Spinophorosaurus nigerensis (Middle Jurassic, Niger)".

El resumen es el siguiente:

Spinophorosaurus is a non-neosauropod from the Middle Jurassic of Niger (Africa) represented by at least two individuals, one with an almost complete axial skeleton, and both specimens with associated skull and appendicular bones. The full preparation and detailed study of the appendicular material is revealing new and important systematic and morpho-funciontal information about this taxon. Both holotype and paratype comprise elements from pectoral and pelvic girdle (scapula, coracoids, clavicles -previously interpreted as tail spikes-, interclavicle, ilium, pubis, ischium) and fore and hind limbs (humerus, femur, tibia, fibula, astragalus, metapodials) being one of the most complete non-neosauropod sauropod found to date. Spinophorosaurus presents a plesiomorphic appendicular skeleton within Sauropoda (e.g. transversely compressed proximal end of the tibia; pubis shorter than ischium, non-coplanar ischial distal end). However, several eusauropod apomorphies are also present such as a scapular blade with a D-shaped cross-section, coracoid dorsal margin lies below the level of the scapular proximal expansion, pubic distal and proximal end in the same parasagittal plan, astragalus is wedge-shaped and the ascending process extends to the posterior edge. Spinophorosaurus presents a specialized and unique scapular girdle (e.g. markedly curved scapular blade, fan-shaped distal expansion) and shares some features with the members of Mamenchisauridae (pronounced posterior flange in the ventral edge of the scapula, fourth trochanter at midline of the femoral posterior face). The systematic analysis of the appendicular skeleton combined with the skull and axial remains indicates that Spinophorosaurus is a member of Eusauropoda more derived than Barapasaurus and Shunosaurus rather than a non-eusauropod.


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