SYSTEMATIC REVISION OF PRE- AND POST-SANTACRUCIAN SPECIES OF PROTYPOTHERIUM (INTERATHERIIDAE, NOTOUNGULATA)

FERNÁNDEZ, M.; FERNICOLA, J.C.; CERDEÑO, ESPERANZA

AMEGHINIANA

ASOCIACION PALEONTOLOGICA ARGENTINA

Lugar: Buenos Aires; Año: 2023

0002-7014

Within the Order Notoungulata, considered the most diverse and abundant clade of South American native ungulates, Interatheriidae (late Paleocene-Late Miocene) is one of the best-known and most derived families. Most of the interatheriids were described during late 19th century from specimens collected from the prolific Santa Cruz Formation (Santacrucian SALMA; Burdigalian-early Langhian), Santa Cruz Province (Argentina). One of the most important interatheriids is Protypotherium, due to its diversity and wide distribution in Bolivia, Chile, Uruguay, and, especially, Argentina. Protypotherium was last revised more than a century ago with most of the species considered Typotheria incertae sedis. More recently, several species were erected within this genus by different authors. This contribution provides the taxonomic revision of the pre- and post-Santacrucian species of Protypotherium, excluding those originally erected by Florentino Ameghino. We propose P. sinclairi and P. concepcionensis as junior synonyms of P. columnifer and P. colloncurensis, respectively, and conclude that Protypotherium includes P. antiquum, P. australe, P. praerutilum, P. compressidens, P. claudum, P. columnifer, P. minutum, P. distinctum, and P. colloncurensis. Finally, we present the most complete phylogenetic analysis of Interatheriidae, at both genus and species levels. It does not recover Protypotherium as a clade, due to the nesting of Caenophilus within the genus, and shows that this assemblage is the sister taxon of the clade constituted by Deseadan Progaleopithecus and Archaeophylus.