Dasymys incomtus rufulus Miller, 1900

Denys, Christiane, Missoup, Alain Didier, Nicolas, Violaine, Sylla, Morlaye, Douno, Mory, Kadjo, Blaise, Lalis, Aude & Monadjem, Ara, 2025, Annotated checklist of rodents from a biodiversity hotspot, Mount Nimba (West Africa), Zoosystema 47 (27), pp. 617-689 : 636

Dasymys incomtus rufulus Miller, 1900

REMARKS

The shaggy rat from Nimba is characterized by a medium-large size and a short tail, nearly identical in length to the head and body (95 to 105%). The dorsal pelage is brown and the ventral one is yellow grey. Our new specimens fit well within the size range of Dasymys rufulus specimens recovered previously on Mount Nimba as well as in Seredou ( Guinea) ( Tables 7 ; 8 ). The skull is robust and characterized by a marked and very narrow interorbital constriction. The braincase is wide with a diamond shape. The nasal bones are enlarged frontally. The incisive foramen is long and ends before the first root of the upper M1/. The molar tooth rows are parallel and large (ratio LS13/LTC: 0.182 -0.205 macrodonty) and the wide M3/ ends up just with the posterior border of the palate. The tympanic bullae are relatively small. The zygomatic arches are enlarged at the level of the maxillary/jugal suture. The mandible is high but short. The skull measurements of the newly collected Guinean specimens fit well with previous measurements collected by Coe (1975) in Liberia, Heim de Balsac & Lamotte (1958) and Roche (1971) in Guinea and with those of the holotype from Mount Coffee ( Liberia).

On the molars, cusps are bunodont and well-aligned transversally on the first upper molar. The median cusps are large and slightly compressed antero-posteriorly. On the upper M1/, there is a stephanodont crest on the t4 and the cusp t6 ends with a longitudinal crest related to the big t8 but no t9 is visible and it is also absent on the upper M2/. On the M2 and M3/ there is a big transverse t1 but no t3. The upper M3/ is longer than the M2/ and has two cusps on the first lobe and one on the second. On the lower molars one can see a tmA and a cv5 on the M/1, no posterior cingulum on the M/1 and a tiny one on the M/2 The M/3 is as long as the M/2 and displays two lobes.