ON THE HOLOTYPE OF CAENOPHILUS TRIPARTITUS AMEGHINO, 1903 (INTERATHERIIDAE, NOTOUNGULATA): REVISION AND CLARIFICATION REGARDING ITS GEOGRAPHIC AND STRATIGRAPHIC PROVENANCES

Abstract

In 1903, Florentino Ameghino erected the genus and species Caenophilus tripartitus based on a mandibular fragment and a lower isolated molar. The former specimen was illustrated about a decade later and it has been considered missing since, at least, 1986. The first review of the species was carried out in 2019, in which the authors presented new materials from Cerro Zeballos (Chubut Province) assigned to this taxon, a new specific description, and a discussion regarding the provenance of the type specimen, due to the contradictions perceived by them in the Ameghino’s papers. Recently, the holotype of Caenophilus tripartitus was located within the Colección Nacional Ameghino at the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”. In this contribution, we present the first study of this holotype in more than a century, concluding that it did not come from the area of Río Fénix and Laguna Blanca, Mayo Formation, but from an uncertain stratigraphic level at the area of Colhué-Huapí, Chubut Province (Argentina). In addition, the comparison with the material from Cerro Zeballos evidences that it is not referable to C. tripartitus and would represent a second species of the genus, Caenophilus zeballensis sp. nov. In this way, the biochron of C. tripartitus is unknown, whereas that of the genus goes back at least to the late Middle Miocene (Serravallian).

Keywords

• Typotheria
• Interatheriinae
• Redescription
• Colhué-Huapí
• Miocene
• Florentino Ameghino