Vertebral pneumatic structures in the Early Cretaceous sauropod dinosaur Pilmatueia faundezi from northwestern Patagonia,Argentina |
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Authors: | Guillermo J. Windholz Rodolfo A. Coria Virginia L. Zurriaguz |
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Affiliation: | 1. CONICET- Instituto de Investigación en Paleobiología y Geología, Sede Alto Valle-Valle Medio-Universidad Nacional de Río Negro, Av. Roca 1242, General Roca, Río Negro, Argentina;2. CONICET-Subsecretaría de Cultura de Neuquén, Museo Carmen Funes, Av. Córdoba 55 (8318), Plaza Huincul, Neuquén, Argentina |
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Abstract: | One of the diagnostic characters of dicraeosaurid sauropods is a reduction of pneumatization of dorsal and caudal vertebrae relative to their Flagellicaudata sister taxon, Diplodocidae. Here, we analyse pneumatic structures in the dicraeosaurid sauropod Pilmatueia faundezi, compare them to those of diplodocoids and report the first record of camerate chambers in a dicraeosaurid. The pneumatic structures are in a posterior cervical centrum (MLL-Pv-002) and consist of lateral pneumatic fossae on the centrum that communicate internally with large camerae. By contrast, Pilmatueia's dorsal and caudal vertebrae (MLL-Pv-005-016) lack pneumatic fossae on the centra, which is consistent with the previously reported reduced pneumaticity in dicraeosaurids. Nevertheless, the base of the neural arch and possibly the base of the bifid neural spines of a posterior dorsal vertebra (MLL-Pv-005) show pneumatic internal chambers. The pneumatic features of the Pilmatueia cervical centrum and dorsal neural arch we describe indicate that the degree of pneumatization is variable within dicraeosaurids. |
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Keywords: | Dicraeosauridae Lower Cretaceous Patagonia Pilmatueia pneumaticity Sauropoda |
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