Rhipidomys ybyrae, Lanes & Bonvicino, 2023

Lanes, Rayque De Oliveira & Bonvicino, Cibele Rodrigues, 2023, Reevaluation of Rhipidomys emiliae (J. A. Allen 1916) and description of a new Rhipidomys (Rodentia: Cricetidae) species from Amazonia and Cerrado, Zootaxa 5346 (5), pp. 581-597 : 591-592

Rhipidomys ybyrae sp. nov.

Holotype: An adult female MN 91158 , prepared as dry skin, cranium and skeleton, cell suspension and tissue, field number CRB 2768, collected by Cibele Rodrigues Bonvicino in 2005, July 14.

Paratype: An adult female MN 91157 , prepared as dry skin, cranium and skeleton, cell suspension and tissue, field number CRB 2761, collected by Cibele Rodrigues Bonvicino in the same locality of the holotype, in 2005, July 14.

Type locality: Brazil, Mato Grosso state, S„o José do Xingu municipality, fazenda S„o Luís. It is in south Amazonia biome, near to “Parque Indígena do Xingu”, created in 1961 and considered the largest and one of the most famous reserves of its kind in the world.

Etymology: This name refers to the arboreal habit of this species, and came from tupi-guarani word, “ybyrá” meaning “tree”, “wood”, “trunk”.

Diagnosis: median sized Rhipidomys species (Total length ~ 275.14 mm; ONL ~ 31.98 mm); dorsal coloration is grayish brown with golden-colored hair at the tips ( Table 2 ). Ventral region ranging from white to light creme color. Tail longer than the head and body length, with a medium-sized tuft in the tip. Dorsal part of the hind feet with a dark dorsal metatarsal patch. Skull of medium size. The interorbital region is moderately wide and converges anteriorly. The zygomatic plate is slightly rounded, inclined anteriorly may have a subtle slope or be completely straight. Shallow zygomatic notch, with nasolacrimal capsule positioned outside the notch and moderately expanded. The Incisive foramina moderately long (IFL ~ 6.36 mm) and narrow (IFB ~ 2.52 mm), in a drop shape, extending or not beyond the procingulum of M1. The mesopterygoid fossa wide and M-shaped, extending to the posterior plane of M3. The subsquamosal foramen is medium sized and rounded anteriorly; hamular process long; and postglenoid foramen small and narrow ( Fig.6 ). Protostyle and enterostyle reduced ( Fig.7 ).

Figures

FIGURE 6. (A) Median-joining network of Rhipidomys sp. nov. (gray), R. ipukensis (black), and R. emiliae (white). Circles represent the haplotypes, and their size is proportional to the number of shared sequences. Haplotype nomenclature is the same of table 1. Numbers adjacent to the lines connecting haplotypes and/or median vector (red circles) are nucleotide substitutions greater than 1. (B) Map with the collecting localities of the samples used in the median joining analysis.

FIGURE 7. View of the superior molar series of (A) Rhipidomys sp. nov. female MN 91157 and (B) R. emiliae male LBCE 12657.