Isothrix negrensis Thomas 1920
Creators: name: Don E. Wilson
name: Thomas E. Lacher, Jr
name: Russell A. Mittermeier
Publisher: name: Lynx Edicions
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Rodentia
Echimyidae
Isothrix
Isothrix negrensis

description: 56.
Rio Negro Brush-tailed Rat
Isothrix negrensis
French: Rat-épineux du Rio Negro / German: Rio Negro-Borstenschwanzratte / Spanish: Rata de cola de cepillo de Rio Negro
Taxonomy. Isothrix bistriala negrensis Thomas, 1920,
“Aca Acajutuba, lower on the Rio Negro, near its mouth” (= a little above Manaus on the Rio Negro, Amazonas, Brazil).
Isothrix negrensis was initially described and subsequently regarded as a subspecies of I. bistriata by earlier workers, but C. R. Bonvicino and colleagues in 2003 elevated it to full species, largely based on karyotypic differences and reciprocally monophyletic molecular clade structure. Monotypic.
Distribution. Amazon Basin of extreme E Colombia and NW Brazil through the Rio Negro Basin, and S of the Amazon River from the lower Rio Jurua E to near the Rio Madeira.
Descriptive notes. Head—body 203-292 mm, tail 182-271 mm. No specific data are available for body weight. The Rio Negro Brush-tailed Rat is a large species of Isothrix, similar in appearance to the Yellow-crowned Brush-tailed Rat (1. bistriata) but differing from that species primarily by its light and marked post-auricular patches and shorter light crown-patch, which ends at middle of ears rather than extending down nape. Ears are buffy rather than whitish. Compared with the Orinoco Brush-tailed Rat (1. ornoci), ramp of the Rio Negro Brush-tailed Rat is more ocherous, and dorsum is slightly darker. Venter is ocherous buff. Tail is 107% of head-body length. Craniodental characteristics of the Rio Negro Brush-tailed Rat are similar to other species of Isothrix, but shorter diastema and deeper cranial vault (when viewed from the side) distinguish it from the Yellow-crowned Brush-tailed Rat and the Orinoco Brush-tailed Rat. Chromosomal complementis 2n = 60 and FN = 112.
Habitat. Seasonally inundated habitats in blackwater igap6 and whitewater varzea from near sea level to elevations of ¢.200 m.
621
Food and Feeding. There is no information available for this species.
Breeding. There is no information available for this species.
Activity patterns. There is no information available for this species.
Movements, Home range and Social organization. There is no information available for this species.
Status and Conservation. Classified as Least Concern on The IUCN Red List. As a rainforest species, the Rio Negro Brush-tailed Rat might be affected by deforestation; however, it occurs in flooded forests that are not highly threatened in the Amazonian region, and much ofits distribution occurs in protected areas. Additional studies on distribution, habitat, abundance, ecology, and conservation threats to Rio Negro Brush-tailed Rat are needed.
Bibliography. Bonvicino et al. (2003), Eisenberg & Redford (1999), Emmons (1990, 1997a, 2005), Patterson & Velazco (2006, 2008), Patton & Emmons (1985), Patton et al. (2015), Tate (1935), Thomas (1920d), Upham et al. (2013), Woods (1993), Woods & Kilpatrick (2005).
description: Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Echimyidae, pp. 552-604 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on pages 582-583, DOI: 10.5281/zenodo.6623649