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| Yamanasaurus lojaensis
Apesteguía, Soto Luzuriaga, Gallina, Granda & Guamán Jaramillo, 2020
Illustration by Jorge Antonio González
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Abstract
Yamanasaurus lojaensis gen. et sp. nov. is a new titanosaur (Saurischia, Sauropoda) from the Upper Cretaceous of the Alamor-Lancones Basin, southern Ecuador. The fossil remains were found in rocks of the Río Playas Formation, which is regarded as Campanian-Maastrichtian in age. Remains include a partial sacrum, a partial mid-caudal vertebra, and several associated limb bones. Yamanasaurus is characterized by: (1) anterior to mid-caudal vertebrae with a dorsoventrally compressed condyle, with the posterior tip elevated respect to the midline, no longitudinal ventral ridge, and spongy inner structure with absence of internal cavities (i.e., camellate bone, shared with Neuquensaurus); (2) last sacral centrum as long as tall, with small ovoid, shallow blind fossa on the lateral side; and (3) radius robust with flattened diaphysis and a marked neck or cingulum right under the epiphysis, with an heptagonal concave proximal surface. Morphology, size, and age suggest that Yamanasaurus is closely related to Neuquensaurus, being the northernmost saltasaurine known by far.
Keywords: Titanosauria, South America, Loja, Late Cretaceous, Saltasaurinae
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| scheme of a Neuquensaurus australis skeleton in order to show the relative size of the specimen and the bones found (in red) |
Systematic Paleontology
Saurischia Seeley 1888
Sauropoda Marsh 1878
Titanosauriformes Salgado, Coria and Calvo 1997
Titanosauria Bonaparte and Coria 1993
Saltasaurinae Powell 1992
Yamanasaurus gen. nov.
Type species: Yamanasaurus lojaensis described below.
Etymology: Genus name refers to the provenance locality, Yamana, in the Casanga Valley, southwestern Ecuador.
Yamanasaurus lojaensis sp. nov.
Etymology: Named after the Province of Loja, where the material was found.
Locality: Yamana region, Paltas Cantón, Loja Province, southwestern Ecuador.
Age and horizon: Late Cretaceous, 66.9 My, late Maastrichtian, Río Playas Formation (= Casanga Formation, Jaillard et al. 1999), Alamor-Lancones Basin.
Sebastián Apesteguía, John E. Soto Luzuriaga, Pablo A. Gallina, José Tamay Granda and Galo A. Guamán Jaramillo. 2020. The First Dinosaur Remains from the Cretaceous of Ecuador. Cretaceous Research. In Press. DOI: 10.1016/j.cretres.2019.104345
