Hylomyscus pamfi, Nicolas, Violaine, Olayemi, Ayodejii, Wendelen, Wim & Colyn, Marc, 2010

Nicolas, Violaine, Olayemi, Ayodejii, Wendelen, Wim & Colyn, Marc, 2010, Mitochondrial DNA and morphometrical identification of a new species of Hylomyscus (Rodentia: Muridae) from West Africa, Zootaxa 2579, pp. 30-44 : 38-40

Hylomyscus pamfi , new species

Holotype. MNHN CG 2010-663 (field number VN 263); adult male; specimen in alcohol; skull complete ( Fig. 5 ); collected by V. Nicolas on 0 8 September 2007. Cryopreserved cells and tissues samples preserved in alcohol are available at the MNHN. 16S rRNA and Cyt b sequences available in GenBank (Accession numbers HM013763 and HM013772 , respectively).

Type locality. Lalama forest, Benin (06°57.867’N; 02°09.741’E).

Paratype. Benin, Gotcha ( MNHN): CG 2010-665 (field number BE0970, young male). Specimen preserved in alcohol, with skull extracted and cleaned. Tissue sample preserved in alcohol is available for molecular studies. Species identification was confirmed by molecular data (16S and Cyt b gene sequencing; GenBank accession numbers HM013761 and HM013771 , respectively).

Etymology. Named after the PAMF, the “Projet d’Aménagement des Massifs Forestiers d’Agoua, des Monts Kouffé et de Wari-Maro”. The two first specimens of this species were captured during a small mammal species inventory conducted for this project. Management programs aiming at preserving forest biodiversity are crucial for the maintenance of this forest species.

Diagnosis. A species of Hylomyscus morphometrically closest to H. simus , but with smaller HBL, TL, HL, EL, DIA2, INTE, BNAS, ROBR and PCPA; and larger UPDA, M1BR, LNAS and LOTE. It can be distinguished from all other species of Hylomyscus based on 16S rRNA and Cyt b sequences.

Description. Pelage soft and fine in texture, short (6–7 mm over middle rump) and close-lying. In living animals, dorsal and flank pelage appears red-brown and ventral pelage appears whitish-grey. Dorsal body hairs dark-grey over most of their length, tipped with bright buff; guard hairs darker, a little longer than body fur. Ventral hairs lighter grey over the basal two-thirds of length, distal third bright white. Dorsal-ventral pelage contrast well marked.Tail markedly longer than head and body (TL: 131±17% of HBL); color greybrown; caudal scales finely textured and hairs short, about one annuli in length; tail thus appearing naked over most of its length, fine hairs becoming macroscopically visible toward the tip; caudal hairs brown. Hind feet short and narrow as for the genus; 5 digits; the 1st digit reaches slightly further than the base of the 2nd digit; digit 5 reaches about two-thirds of digit 4; plantar surface naked, with 6 well-formed pads. In the fore foot, the thumb is rudimentary and bears a flat nail; the 5th digit is long, approximately equal to the 2nd. Top of fore feet covered with short white hairs. Top of hind feet covered with short white (on edges) and brown (in the center) hairs. Nails covered by white hairs tufts. Mammae pattern: 2 pectoral and 2 inguinal pairs.

Braincase smooth, cranial vault markedly arched, especially over the parietals- interparietal ( Fig. 4 ). Interorbit relatively narrow, lacking supraorbital ridging or beading; interorbital borders mostly amphoral in shape. Zygomatic arches parallel-sided or slightly convergent rostrally; anterior edge of zygomatic plate more or less straight and perpendicular.

Incisive foramen terminating posteriorly just short of or equal to the anterior root of M1.

Palate smooth, slightly concave; posterior palatal foramina a single pair, set at the level of the 3rd lamina of M1. Mesopterygoid fossa narrow and elongated, its anterior border roughly squared. Coronoid process short and pointed.

Upper incisors orthodont, enamel face yellow-orange. Enamel face of lower incisors yellow. Upper toothrows nearly parallel. Breadth of M2 approximately equal to breadth of M1 (or slightly larger); breadth of M3 smaller. On M1, t3 is poorly defined, t7 is absent and t9 is present. On M2, t2 is absent; t3 is present, but is small; t7 and t9 are as on M1. On M3, t3 is absent (except in the young specimen MNHN CG 2010-665).

Distribution. Known collecting localities of the species are presented in Figure 6 . Our DNA analyses confirmed the presence of Hylomyscus pamfi in at least 3 localities of Benin (Lougba, Gotcha and LaLama) and 2 localities of Nigeria (Asejire and Osogbo). According to our morphometrical data this species also occurs in Togo (Palimé). Additional sampling in the region of the Dahomey gap ( Ghana, Togo and Benin) and in eastern Nigeria are necessary to precisely define the geographical distribution of the species.

Ecology. Hylomyscus pamfi is a forest-dwelling species. In Gotcha, Asejire and Osogbo all specimens were captured in dense forest. In LaLama, one specimen (the type) was captured in the dense forest of the “Noyau central” of LaLama forest, and one specimen was captured in the village of Koto. In Lougba, they were captured in open forest.

Additional specimens. In order to craniometrically characterize the new taxon and to study its nature and extent of genetic variation, we included in our analyses numerous other specimens from the type locality and from other localities (see Appendices 1 and 2).

Figures

FIGURE 5. Photographs of the dorsal, ventral, and lateral views of the skull of the holotype of Hylomyscus pamfi, new species (MNHN CG 2010 - 663), and the lateral view of its left mandible.

FIGURE 6. Collecting localities of Hylomyscus pamfi positively identified by molecular data (black dots) or by morphometrical data (grey square). Forests are in light grey on the general map (adapted from Mayaux et al., 2004).

FIGURE 4. A scatterplot of the 1 st and 2 nd canonical variates axes from a canonical variates analysis of 3 operational taxonomic units (Hylomyscus alleni, H. simus and H. nsp). Group centroids (dots) and extreme limit of each scatterplot of points are indicated. Ten specimens from Togo were plotted on the graph (black squares). Holotypes are represented by a cross.