Reassessment of the hairy long-nosed armadillo “Dasypus” pilosus (Xenarthra, Dasypodidae) and revalidation of the genus Cryptophractus Fitzinger, 1856

Abstract

The hairy long-nosed armadillo, currently referred as Dasypus (Cryptophractus) pilosus, is an enigmatic species endemic to montane cloud forests and subparamo of Peruvian Andes. Its strikingly different external features, which include the carapace concealed by abundant hair, the presence of more movable bands, and a slender skull, have raised questions regarding its taxonomic status as subgenus or as genus. This paper assesses this issue based on a cladistic study and provides a detailed comparative description of the species, including the first account on the distinctive ornamentation of its osteoderms. Based on several unique characters in the carapace, skull, mandible, and teeth, as well as on the external phylogenetic position relative to other Dasypus, we favor the assignment of the hairy long-nosed armadillo to other genus. As result, we revalidate the original generic epithet, so that the valid name of the species is Cryptophractus pilosus Fitzinger, 1856.

Taxonomic revision of the long-nosed armadillos, Genus Dasypus Linnaeus, 1758 (Mammalia, Cingulata)

“…kappleri (sensu lato) is the sister taxon of all other Dasypus species, while D . pilosus is the last lineage to diverge, contrary to the results of Castro et al [6]. …”

“…kappleri with extinct Propraopus and Dasypus bellus , and suggested that they belong to the same taxon, recognizable either as a subgenus or genus. Castro et al [6] proposed recognizing D . (Crypthophractus) pilosus as a distinct monotypic genus, based on its exclusive traits and its external position in their cladistic morphological analysis.…”

“…Because Dasypus is the only living representative of an ancient lineage of armadillos, and its species are not only morphological and molecular relatives but also share a unique reproductive system and ecological traits, we here consider Dasypus as a polytypic genus, with eight extant species. We do not follow the subgeneric classification used by Wetzel and Mondolfi [36], as those groups are not monophyletic according to available phylogenetic studies [6,10]. …”

“…It has the widest distribution of the order, occurring from Argentina to the United States, encompassing the latitudes from 39°S to 40°N [4]. The monophyly of the genus is well supported both by morphological [5,6] and molecular data [7,8,9,10]. Dasypus is the only living representative of the subfamily Dasypodinae (or Dasypodidae according to Gibb et al [10]) and diverged from other armadillos during the Neogene.…”

Comparative histology and ontogenetic change in the carapace of armadillos (Mammalia: Dasypodidae)

“…Therefore, the Dasypodinae mostly have a poor hair development (except for Cryptophractus pilosus, a species located in very high areas in the Peruvian Andes, see Castro et al 2015), while Euphractinae have a greater hair development and large deposits of adipose tissue, which could provide a greater thermal insulation and reduction in the thermal conductance. In turn, the greater glandular development in Euphractinae could be associated with more arid and harsher environments with drier and sandier soils, which would involve a greater necessity of substances to maintain the ectodermic structures moist.…”