Untangling the taxonomic validity of Asterostemma Ameghino (Xenarthra, Cingulata, Glyptodontidae)

• Autores: Martini, Gastón Andrés; Olivieri, Shirley Fabiela; Gonzalez Ruiz, Laureano Raul
• Año de publicación: 2023
• Idioma: inglés
• Tipo de recurso: documento de conferencia
• Materia: TAXONOMIC; CINGULATA; GLYPTODONTIDAE; ASTEROSTEMMA
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Ameghino described the glyptodont Asterostemma, including originally three species (A. depressa, A. granata, and A. laevata) all based on osteoderms of the carapace from “Barrancas del Río Chico”, Santa Cruz Province, Argentina (Santa Cruz Formation, Early Miocene). Currently, Asterostemma is represented by two valid species: A. depressa, the type species, and A. barrealense. According to that, the objective of this contribution is to analyze the validity of both of them, and perform a revision of the assigned specimens. Asterostemma depressa was described by Ameghino in 1889 from at least two fragments of carapace. The osteoderms have a typical “rosette” pattern, with the central figure posteriorly displaced and well-marked sulci. The type material is currently lost (but described and figured by Ameghino) in the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” (MACN-A, Colección Nacional Ameghino) in Buenos Aires Province, and the description and illustrations of Ameghino do not offer diagnostic characters (e.g., a central figure surrounded by peripheral figures = rosette pattern) that allow to allocate or differentiate it from previously described glyptodonts from the Early Miocene (e.g., other Propalaehoplophoridae species). Asterostemma barrealense was described by Rusconi in 1946 from one fragment of carapace. The osteoderms have a typical “rosette” pattern, with the central figure posteriorly displaced and poorly marked sulci. The type material is located in the Museo de Ciencias Naturales y Antropológicas “Juan Cornelio Moyano” (MCNAM PV 154, type), in Mendoza Province. Of the two species, only A. depressa has specimens assigned to it, including a carapace fragment (MACN-A 1041), four osteoderms (MACN-A 4747–50), a portion of the cranium with molariforms, two osteoderms, a fragment of caudal armor, a fragment of carapace (MACN-A 7663–66), a fragment of the palate and a fragment of the caudal armor (MACN-A 7667), a fragment of the carapace (MACN-A S/N), and a caudal armor located in the Peabody Museum of Natural History, Yale University, U.S.A. (YMP VPPU 16001), but none of the assignations were justified. In summary, we found no diagnostic characters in the description and illustration of the type specimens of A. depressa or in the type specimen of A. barrealense that clearly justifies the recognition of two different species of Propalaehoplophoridae glyptodonts.
Fil: Martini, Gastón Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónica. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina
Fil: Olivieri, Shirley Fabiela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónica. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina
Fil: Gonzalez Ruiz, Laureano Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónica. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina
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Argentina
Asociación Paleontológica Argentina
Universidad Nacional de Río Negro