Isothrix barbarabrownae Wagner 1845
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 barbarabrownae

description: 54.
Barbara Brown’s Brush-tailed Rat
Isothrix barbarabrownae
French: Rat-épineux de Brown / German: Barbara Brown-Borstenschwanzratte / Spanish: Rata de cola de cepillo de Barbara Brown
Taxonomy. Isothrix barbarabrownae Patterson & Velazco, 2006,
“Km 138.5 on the Carretera Paucartambo-Shintuya, near ‘Suecia’ (a roadside restaurant), 1900 m, Provincia de Paucartambo, Departamento de Cuzco, Peru,” in the Cultural Zone of the Manu National Park and Biosphere Reserve at 13°6:032’S, 71°34-124’W.
This species is monotypic.
Distribution. SE Peru, known only from the type locality in the Cultural Zone of the Manu National Park and Biosphere Reserve.
Descriptive notes. There are no specific measurements available. Barbara Brown's Brush-tailed Rat is known only from the holotype, a subadult specimen without erupted third molars; neither external measurements nor weight were provided in the original description. Furis lax and long, with hairs reaching 20 mm on back and 10 mm on venter. Dorsal pelage is agouti, gray at base, cinnamon or reddish brown for most of its length, with blackish tips; muzzle is grayish; and crown of head is colored similarly to back, thus lacking differentially colored stripe that characterizes most other species of Isothrix. White-tipped hairs cover flank, neck, and shoulders, and ventral color is only indistinctly separated from that on flanks. Crest of longer hairs is present in supraorbital region. Underfur is also dense, long, and wavy. Tail is densely furred along its entire length, covered by hairs 10 mm long and oriented perpendicularly to its axis. Tail color varies along its length from cinnamon at base, black through mid-part, and white at terminus. Scales remain slightly visible. Forehead and cheeks are washed with snuff brown color. Ear pinnae are burnt umber and mostly naked, except for elongated tuft on crown. Eyelids are fleshy, except for an elongate tuft of hairs. The single specimen retains craniodental characteristics typical of other species of Isothrix: rostrum is short and broad; zygomatic arch is bowed strongly outward and anterior to squamosal; auditory bullae are only slightly inflated and bear medium-sized meatus with distinctively short auditory tube that strongly slants forward. There is distinct slit between basisphenoid and presphenoid sutures. Squamosotympanic fenestra is long and openly rounded vacuity, posteriorly reaching base of supraoccipital process, which is connected to another slit-shaped vacuity along presphenoid and thus shaped like an apostrophe. Pterygoid region has no shelf behind base of hamular processes on wall of buccinator foramen. Mesopterygoid fossa is deep, extending forward to level of second molars. Incisive foramina are wide and broad. Jaws have strongly developed masseteric bases and pterygoid crests. Mandibular foramen is anterior to condyloid ridge and not contained within fossa. Maxillary cheekteeth are short and small compared with skull length. Cheekteeth are sub-circular with occlusal plane nearly parallel to palate. Hypoflexis(ids) of maxillary and mandibular cheekteeth are oval to sub-circular with mure. Loph (id)s just aside hypoflexi(id)s are curved around to molar edge, giving typical shape to teeth of all species of Isothrix. Lower dP, is pentalophodont, with short hypoflexid, mure, and parallel flexids. Distinct skull characteristics of Barbara Brown's Brush-tailed Rat include more compact skull, non-swollen braincase, shallower temporal fossa, narrow and triangular infraorbital foramina, incisive foramina with well-developed maxillary septum, narrow palate, broad foramen magnum with distinct medial notch, and small auditory bullae.
Habitat. Montane and elfin forest habitats at elevations of ¢.1850 m. Barbara Brown's Brush-tailed Rat is presumably arboreal but was collected on the ground near a road bordered with ferns, mosses, and bryophytes near aforest. A second individual was sighted at night near the road in a rocky crevice with dry grasses.
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 Data Deficient on The IUCN Red List. Additional studies on distribution, habitat, abundance, ecology, and conservation threats to Barbara Brown's Brush-tailed Rat are needed, but the single known locality is within a protected zone.
Bibliography. Patterson & Velazco (2006, 2008), Patton et al. (2015), 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 page 582, DOI: 10.5281/zenodo.6623649