Dicranocentrus melinus

Description. Body length: 3.5 mm to 4.0 mm. Habitus elongated typical of genus. General color strongly yellowish with brownish scales. Antennae and legs with dark bluish pigmentation (Fig. 1). Head. Antennae long, approximately three to four times the length of cephalic diagonal. Ratio of antennal segments I: II: III: IV: V: VI = 1.0: 3.1: 1.5: 3.8: 11.8: 4.7 (Fig. 2). Ant. I – IV with ciliated microchaetae interspersed with smooth chaetae and small scales. Ant. V with sensory organ located in the distal dorsolateral region, composed of two robust rod-like sensilla, individually covered by a tegument fold and protected laterally by guard sensilla and ciliated chaetae (Fig. 3). Ant. VI with one subapical pin seta ventrally; apical bulb absent (Fig. 4). Ant. V and VI annulated, with ciliated microchaetae interspersed with smooth chaetae arranged in rings on finely granulated tegument and without scales. Eyes 8 + 8 in strongly pigmented eye patch, G and H eyes smaller than others (Fig. 5). Pre-labral chaetae simple; labral chaetotaxy 4 / 5,5,4, all chaetae smooth; labral papilla of type II (Fig. 6). Maxillary palp simple with basal chaeta subequal to apical chaeta, and 4 sublobal hairs (Fig. 7). Outer labial papilla with a small lateral process reaching half of papilla E; 5 guard chaetae present (e 1, e 3, e 4, e 5 and e 6) (Fig. 8). Labial triangle with chaetae M 1 and M 2 ciliated, chaeta r smooth and smaller than chaeta E (Fig. 9). Appendages. Trochanteral organ consisting of approximately 65 small spines and subequal smooth chaetae; approximately 50 ciliated mesochaetae laterally and few small scales; trochanteral chaeta longer than trochanter (Fig. 10). Tibiotarsi covered with numerous ciliated chaetae and small scales; one row of spiny ciliated chaetae and one smooth chaeta on inner margin. Unguis long and robust with a pair of basal teeth and a distal unpaired tooth on inner margin, two lateral and one dorsal basal teeth; unguiculi lanceolate with a median inner tooth; tibiotarsal tenent hair elongate and capitate (Fig. 11). Ventral tube covered with 20 + 20 subequal ciliated mesochaetae and 3 + 3 ciliated macrochaetae anteriorly; ciliated chaetae of various sizes interspersed with scales posteriorly; approximately 40 smooth and ciliated mesochaetae laterally (Fig. 12). Tenaculum well developed, with 4 + 4 teeth and one ciliated macrochaeta in basomedian region (Fig. 13). Dens long, crenulate, with about 55 spines only in the inner basal area (Fig. 14); distal part of dens smooth and measuring about twice mucro’s length. Mucro small with two teeth and one basal spine (Fig. 15). Macrochaetotaxy. Head with 13 + 13 chaetae on antennal group (An); anterior group with 4 + 4 chaetae (A 2, A 3, A 4 and A 5) and unpaired chaeta A 0; median-ocellar line with 3 + 3 chaetae (M 1, M 2 and M 3); sutural group with 6 + 6 chaetae (S 1, S 3, S 4, S 5, S 6 and S 7) and unpaired chaeta S 0; post sutural chaeta (Ps) absent; post ocellar chaeta (Po) present; posterior group (P) with 4 + 4 chaetae (Fig. 16). Th. II with 2 + 2 inner Mc., 4 + 4 outer Mc. in median region and 6 + 6 posterior Mc.; Th. III with 9 + 9 Mc.; Abd. I with 5 + 5 Mc.; Abd. II with 2 + 2 inner and 1 + 1 outer Mc.; Abd. III with 2 + 2 inner and 2 + 2 outer Mc.; Abd. IV with 5 + 5 inner Mc. (Fig. 17).

Discussion. The species Dicranocentrus melinus sp. nov. belongs to gracilis - group sensu Mari Mutt, 1979 together with D. schoetti Mari Mutt, 1979 and D. heloisae Arlé & Mendonça, 1982 due to the absence of chaeta A 1, S 2, Ps and up to 6 + 6 chaetae P on dorsal head. The new species is similar to D. schoetti Mari Mutt, 1979, described from Peru, by the presence of pin seta, G and H eyes reduced, guard chaetae e 1, e 3, e 4, e 5 and e 6 on outer labial papilla, smooth chaetae on metathoracic tibiotarsi, capitate tenent hair, absence of spines on outer basal region of dens, and 4 + 4 P chaetae dorsally on head. However, D. melinus sp. nov. shows labral papilla type II according the classification preconized by Mari Mutt (1981), maxillary palp with basal chaeta subequal to apical chaeta, ciliated chaetae on labial triangle, unguis with three teeth on inner margin, 12 + 12 Mc. on Th. II, 3 + 3 Mc. on Abd. II and 5 + 5 Mc. on Abd. IV. According Mari Mutt (1979), D. schoetti exhibits labral papilla type III, maxillary palp with basal chaeta longer than apical chaeta, labial triangle without ciliated chaetae, unguis with four teeth on inner margin, 11 + 11 Mc. on Th. II, 2 + 2 Mc. on Abd. II and 6 + 6 inner Mc. on Abd. IV.

Etymology. The name melinus, derived from the Greek word meli that means honey, in a reference to the coloration displayed by the new species.

Type locality. “ Parque Nacional da Serra do Gandarela ”, Caeté municipality, Minas Gerais State, Rain forest litter, lat / long coordinates 20 ° 1 ' 49.91 " S; 43 ° 40 ' 43.83 " W, about 1500 meters a. s. l. Type material. Holotype: male, slide 2276 a CM / MNRJ, 29 – 02 / XII / 2011, Abrantes E. A. & Silveira T. C. leg. Paratypes: slides 2273 a CM / MNRJ, 2273 b CM / MNRJ, 2273 c CM / MNRJ, 2273 d CM / MNRJ and 2273 e CM / MNRJ, 29 - 02 / XII / 2011, Abrantes E. A. & Silveira T. C. leg.; slide 2277 CM / MNRJ, 29 – 02 / XII / 2011, Abrantes E. A. & Silveira T. C. leg.; slide 2279 CM / MNRJ, 29 – 02 / XII / 2011, Abrantes E. A. & Silveira T. C. leg.; slide 2281 CM / MNRJ, 29 – 02 / XII / 2011, Abrantes E. A. & Silveira T. C. leg.; slides 2285 a CM / MNRJ and 2285 b CM / MNRJ, 29 – 02 / XII / 2011, Abrantes E. A. & Silveira T. C. leg.; slide 2289 CM / MNRJ, 29 – 02 / XII / 2011, Abrantes E. A. & Silveira T. C. leg.; slide 2293 CM / MNRJ, 29 – 02 / XII / 2011, Abrantes E. A. & Silveira T. C. leg.