Distribution and current state of knowledge of Hoffmann’s two-toed sloth (Choloepus hoffmanni) in Colombia, with comments on the variations of its external morphological traits

Abstract

Hoffmann's two-toed sloth (Choloepus hoffmanni) has been extensively studied since the 1940s in some countries across its distribution range. However, several aspects of its biology remain unexplored or have only been described superficially. This study updated the geographic distribution of this sloth species in Colombia, describing external features of specimens that inhabit different areas of the country. Additionally, a revision of the current state of knowledge of this species in Colombia was conducted, with a focus on the identification of information gaps and the major threats affecting this species. An updated map of the distribution of C. hoffmanni in Colombia was elaborated, including the distribution reported by IUCN, the records of specimens received in the Xenarthra center for rescue and rehabilitation (CRRX, for its acronym in Spanish; primary information), the wildlife care centers of the Autonomous Regional Corporations (CARs, for its acronym in Spanish), and records of biological collections available online (secondary information). CRRX specimens were examined externally, and the external morphological characteristics (skull and body shape; pelage color, length and density) were described. A comprehensive literature review was performed, compiling studies conducted over the last two decades on this species in Colombia, analyzing their respective contributions to its knowledge. The records obtained provide localities of occurrence for the species not previously recognized by IUCN, in 54 municipalities of 12 departments of Colombia. There are external morphological patterns defining lowland (interandean valleys and Caribbean region), highland (Colombian Andes) and Colombian Pacific populations. The biggest information gaps regard demography, distribution and genetics. The main threats identified are habitat loss (infrastructure construction, forest clearance) and specimen collection (illegal trade). The localities of occurrence obtained confirm the distribution of this species in areas previously reported at the north and center of the Cordillera Occidental, Cordillera Central and Cauca River valley, besides the north, center and south of the Cordillera Oriental, Piedemonte Llanero, and the southern Magdalena River valley. The external review of specimens by CRRX shows that although it is impossible to derive clear taxonomic inferences from the evidence collected, pelage color, length and density are the most representative external traits that differentiate lowland, highland and Pacific Colombian populations. The prioritization of issues such as the conservation status and threats in the investigation of this species in Colombia during the last twenty years have relegated key aspects such as demography, distribution, taxonomy and genetics, a fact that poses a challenge for the execution of proper management actions in the country.