New specimen of Pucatherium parvum (Xenarthra, Dasypodidae), a singular dasypodid of the Paleogene (Eocene) of Northwest Argentina. Importance in the early evolution of armadillos

HERRERA, CLAUDIA ; ESTEBAN, GRACIELA; CIANCIO, MARTÍN R.; DEL PAPA, CECILIA

JOURNAL OF VERTEBRATE PALEONTOLOGY

SOC VERTEBRATE PALEONTOLOGY

Lugar: Lawrence; Año: 2019 p. 1 - 11

0272-4634

A new specimen of Pucatherium parvum from the lower levels of the Upper Lumbrera Formation of Salta Province is reported. An almost complete dorsal carapace and several postcranial remains were preserved, providing important information about this particular taxon. The specimen is comparable in size to Dasypus novemcinctus, although the osteoderms are very small. The dorsal carapace seems to be completely integrated by movable osteoderms, providing a high degree of mobility in the anteroposterior axis. There is no evidence of pseudoshield, scapular shield or pelvic shield. The dating of 39.9 ± 0.4 Ma (U / Pb zircon), taken from a tuff close to the top of the Upper Lumbrera Formation, allows to refer this record of Pucatherium parvum to the middle Eocene (Bartonian) (del Papa et al., 2010). This, together with its broad geographic distribution, allows correlating the Upper Lumbrera Formation with the Quebrada de los Colorados Formation in Salta Province, and the Casa Grande Formation, in Jujuy province. On the other hand, the estimated depositional age of 37.3 - 35.4 Ma, for the Geste Formation in the Salta province, extends the biocron of P. parvum to the late Eocene.