EXPLORING THE PRESENCE OF “HORNS” AND CRANIUM PROTUBERANCES IN CINGULATA (MAMMALIA, XENARTHRA)

GONZÁLEZ RUIZ, LAUREANO RAÚL; MARTINI, GASTÓN ANDRES; OLIVIERI, SHIRLEY FABIELA

La Rioja

Congreso; Jornadas Argentinas de Paleontología de Vertebrados; 2023

Asociación Paleontológica Argentina

The objective of this contribution is to expand the knowledge of cranial structures commonly known as “horns” and cranium protuberances in fossil and extant Cingulata (Mammalia, Xenarthra). We use high-resolution X-ray computed tomography and imagery to analyze these structures present in three “armadillos”, Peltephilus Ameghino, 1887 (“horned armadillo”), Calyptophractus Fitzinger, 1871 (“larger fairy armadillo”), Chlamyphorus Harlan, 1825 (“pink fairy armadillo”), and in one glyptodont, Glyptodontidae gen. et sp. indet. In Peltephilus (MACN A 7784-91, Santa Cruz Formation, Miocene, Argentina) and Glyptodontidae gen et sp. indet. (LIEB PV 6089, Collón CuráFormation, Miocene, Argentina) this structure results from the modification of osteoderms from thecephalic shield, meanwhile in Calyptophractus (USNM 28314, extant, Bolivia) and Chlamyphorus(AMNH 5487, extant, Argentina) results from a modification of cranium bones. Preliminary results,indicate that Peltephilus has two osteoderms of subpyramidal shape on the nasal region,Glyptodontidae gen. et sp. indet. has four osteoderms of subpyramidal shape on the frontoparietalregion, Calyptophractus has two small protuberances on the frontals not contacting the cephalicshield, and Chlamyphorus has two large protuberances on the frontals contacting the cephalic shield. The function of these structures is still unknown, and further studies could clarify this aspect.