Neosclerocalyptus was an extinct genus of glyptodont that lived during the Pliocene, Pleistocene, and Holocene of Southern South America, mostly Argentina. It was small compared to many Glyptodonts at only around 2 meters long and 360 kilograms.
Etymology
The genus name Neosclerocalyptus is a modification of the name of its synonym, Sclerocalyptus, and derived from the Greek roots neo- meaning "young" or "new", scleros meaning "hard", and -calyptos meaning "covering", referring to the armored carapace of the animal. The type species, N. ornatus, specific name meaning is "adorned" after the patterns on the holotype osteoderms.
History and taxonomy
Fossils of Neosclerocalyptus were first collected by a "Sir Woodbine Parish, KH" from the Pleistocene strata near the Matanzas River in Buenos Aires Province, Argentina, but where later sent to the Royal College of Surgeons in the UK, where they were later described by paleontologist Sir Richard Owen in 1845 as a species of the earlier named Glyptodon, naming it Glyptodon ornatus. The fossils were fragmentary, consisting only of 4 dorsal carapace osteoderms, but were destroyed during German bombing raids during World War II. The strata where the fossils were collected may be from the Ensenadan of the Pleistocene based on later analysis of the strata around the Matanzas River. Due to the fossils being lost, a neotype was designated by Richard Lydekker in 1887 that consisted of a complete dorsal carapace, caudal rings, and a caudal tube that were also collected from Buenos Aires and deposited in the collections of the Museo Argentino de Ciencias Naturales Bernardino Rivadavia, but it couldn't be found in the museum's collections. Lydekker illustrated a complete skeleton with a complete carapace in 1894 that had been collected from the Ensenadan deposits of the Mar del Plata in Buenos Aires that is extremely similar to that of the neotype and has been used as the "model" specimen of the species since. This is shown by Argentine paleontologist Florentino Ameghino when he stated, "It is a superb sample of a fully grown adult (.) and it should be preferably consulted by paleontologists because it represents approximately the actual shape of the animal".
One of the best known species, N. pseudornatus, was first described by Florentino Ameghino in 1889 based on 13 dorsal carapace osteoderms that were collected from the Pleistocene strata in the "Toscas del Rio de La Plata" in Buenos Aires, though Ameghino named it as a species of the Brazilian glyptodont Hoplophorus. Since its naming, dozens more specimens have been assigned to N. pseudornatus, including skulls. In 1891, Ameghino erected the genus name Sclerocalyptus for the Brazilian glyptodont Hoplophorus euphractus, erroneously believing that the genus name was preoccupied, and placed Glyptodon ornatus and Hoplophorus pseudornatus among other species in the genus. Subsequently it was clear that these two species differ considerably with each other and, due to the rules of zoological nomenclature, the name Sclerocalyptus was considered synonymous with Hoplophorus (described first), and it was necessary to establish a new genus for Sclerocalyptus ornatus: Paula Couto, in 1957, then established the Neosclerocalyptus genus. The taxonomic confusion concerning the names of this species continued throughout the twentieth century and for the first part of the 2000s, but N. ornatus has consistently been seen as valid and the type species. Other species named include N. castellanosi (late Pliocene), N. pseudornatus (lower Pleistocene - Medium), N. gouldi (middle Pleistocene) and N. paskoensis (late Pleistocene-early Holocene). However, many other species that have been named have been synonymous with previously named species or synonymous with other genera, most of them named based on fragmentary fossils.
Species
The following list is after Quiñones et al (2020), Zurita et al (2009), and Zurita (2007). Zurita et al (2009) argued that only 2 species of Neosclerocalyptus are valid (N. ornatus & N. pseudornatus), but subsequent analyses have kept 5 species as valid.