Carebara mahafaly Azorsa & Fisher

Azorsa, Frank & Fisher, Brian L., 2018, Taxonomy of the ant genus Carebara Westwood (Formicidae, Myrmicinae) in the Malagasy Region, ZooKeys 767, pp. 1-149 : 1

Carebara mahafaly Azorsa & Fisher sp. n.

Holotype.

(major worker), MADAGASCAR, Antananarivo , 3 km 41° NE Andranomay, 11.5 km 147° SSE Anjozorobe, -18.47333, 47.96, 1300 m, montane rainforest, 5-13.xii.2000, (Fisher, Griswold et al.). Collection code BLF02378, (CASC: CASENT0410500). Paratypes: (1 major worker and 5 minor workers), with same data as holotype, 5 minor workers (BMNH: CASENT0410532, CASC: CASENT0410533, CASENT0410536, CASENT0410535, MCZ: CASENT0410537). 1 major worker with same data as holotype but with different collection code, BLF02371 (CASC: CASENT0410502).

Diagnosis.

Antennae ten-segmented. Major: Head slightly longer than wide, nearly subquadrate, lateral margins strongly convex; posterior margin of head deeply concave; dorsum of propodeum weakly convex, nearly flat; posterodorsal corner of propodeum with a pair of laminate triangular teeth; petiolar node thick, combined outline of dorsal surface of peduncle and anterior face of node concave and posterior face vertical and weakly convex; gaster with short appressed hairs. Minor: Head slightly longer than wide, narrowed anteriorly; lateral margins of head slightly convex; posterior margin of head straight; dorsum of propodeum medially concave, posterodorsal corner with a pair of laminate triangular teeth; petiolar node thick, combined outline of dorsal surface of peduncle and anterior face of node slightly concave in the middle, dorsum slightly convex; gaster with short appressed hairs.

Description of major workers.

Measurements (n=2): HL 0.65-0.75 (0.65); HW 0.58-0.65 (0.58); SL 0.31-0.32 (0.32); ML 0.15; EL 0.02-0.03 (0.02); EM 0.20-0.21 (0.20); HD 0.38-0.42 (0.38); WL 0.56-0.61 (0.56); PSL 0.08-0.09 (0.09); PW 0.30-0.36 (0.30); MFL 0.34-0.37 (0.34); MFW 0.07-0.09 (0.07); MTL 0.27-0.31 (0.27); PTL 0.22-0.25 (0.22); PNL 0.09-0.11 (0.09); PTH 0.17-0.18 (0.17); PTW 0.12-0.15 (0.12); PPL 0.13-0.14 (0.14); PPNL 0.10-0.13 (0.10); PPH 0.12; PPW 0.17-0.20 (0.17); GL 0.49-0.62 (0.49); GW 0.45-0.54 (0.45); CI 87-88 (88); MI 20-23 (23); SI 41-49 (49); MLI 57-59 (59), PPLI 52-64 (64); PPI 133-142 (142); PSI 12-16 (16).

Head slightly longer than wide (CI 87-88), in full-face view nearly subquadrate, about 1.1 times longer than wide. Posterior margin of head deeply concave in the middle, posterolateral corners well developed and rounded, lateral margins strongly convex. Mandibles with six teeth. Anterior margin of clypeus nearly straight, and laterally convex. Ocelli present or absent. Antennae with ten segments. Scapes short (HL 0.65-0.75, SL 0.31-0.32, SI 41-49). Eyes present, consisting of one ommatidium (EL 0.02-0.03). Supraclypeal area acutely triangular and well defined.

In profile view, promesonotum high and strongly convex, metanotal groove deeply impressed, propodeum about 1.8 times higher than long, and lower than promesonotum, dorsal face of propodeum nearly flat and declining posteriorly, propodeum armed, posterodorsal corners each armed with a triangular laminate tooth, anterodorsal corner slightly convex, declivity weakly concave, nearly flat, with thin lateral laminae. Propodeal lobes convex. Propodeal spiracle rounded and situated above mid-height of sclerite by about the diameter of the spiracle, and beyond mid-length of sclerite by about half the diameter of the spiracle, distance from propodeal spiracle to posterodorsal corner of propodeum about 3.5 times the diameter of the spiracle (PSL 0.08-0.09), and distance to declivity about 2.2 times the diameter of the spiracle. In dorsal view, promesonotum about as long as wide, anterior margin and sides of promesonotum rounded and narrowed posteriorly; sides of propodeum straight.

Petiole longer than high (PTL 0.22-0.25, PTH 0.17-0.18) and with relatively long peduncle, ventral face medially convex. Combined outline of dorsal surface of peduncle and anterior face of node medially concave, posterior face of node vertical and nearly straight, anterodorsal corner strongly convex, posterodorsal corner rounded, dorsum convex. Subpetiolar process absent, when present, reduced to a small convexity. Postpetiolar node nearly rounded and lower than petiolar node. In dorsal view, postpetiolar node wider than petiolar node (PTW 0.12-0.15, PPW 0.17-0.20) and petiolar node wider than long (PNL 0.09-0.11, PTW 0.12-0.15), anterior margin of petiole straight, posterior margin convex, anterior margin of postpetiole concave and posterior margin convex, sides rounded in petiole and postpetiole.

Dorsal surface of mandibles, clypeus, supraclypeal area and the median portion of the frons smooth and shiny, with scattered piligerous punctae on head and mandibles. Head with finely longitudinal and parallel rugae, except for median area and near posterior margin, gena with longitudinal rugae, extending to eye level, frontal lobes with longitudinal rugae, extending to antennae level. In profile, posterolateral portion of cephalic dorsum smooth and shiny. Mesosoma smooth and shiny, except katepisternum and metapleuron (areolate-rugose), and propodeum (areolate). Petiole and ventral face of postpetiole areolate. In dorsal view, promesonotum, petiole, postpetiole and gaster smooth and shiny except for propodeum which is areolate.

Lateral margins of head with short appressed hairs, posterior margin with short and long subdecumbent hairs. Scapes with appressed hairs. Outer margin of mandibles with short and sparse appressed hairs. Mesosoma with short and long suberect hairs. Petiole and postpetiole with short appressed hairs and long subdecumbent hairs. Tibia with short appressed hairs. Gaster with short appressed hairs and sparse and long decumbent hairs. Color yellowish ferruginous.

Description of minor workers.

Measurements (n=7): HL 0.37-0.46; HW 0.32-0.42; SL 0.23-0.29; ML 0.09-0.11; EL 0.01-0.02; EM 0.11-0.15; HD 0.22-0.29; WL 0.35-0.46; PSL 0.04-0.06; PW 0.19-0.24; MFL 0.22-0.31; MFW 0.05-0.07; MTL 0.17-0.25, PTL 0.13-0.18; PNL 0.06-0.08; PTH 0.10-0.13; PTW 0.08-0.10; PPL 0.08-0.10; PPNL 0.07-0.10; PPH 0.07-0.10; PPW 0.11-0.15; GL 0.30-0.45; GW 0.23-0.35; CI 86-93; MI 22-26; SI 61-66, MLI 69-74; PPLI 56-63; PPI 130-150; PSI 11-14.

Head longer than wide (CI 86-93), in full-face view nearly subquadrate, about 1.1 times longer than wide and slightly narrowed anteriorly. Posterior margin of head nearly straight, posterolateral corners rounded, lateral margins convex. Mandibles with five teeth. Anterior margin of clypeus slightly concave, and laterally convex. Antennae with ten segments. Scape fails to reach the posterior margin of head (HL 0.37-0.46, SL 0.23-0.29, SI 61-66). Eyes present, consisting of one ommatidium (EL 0.01-0.02). Supraclypeal area triangular but poorly defined.

In profile view, promesonotum weakly convex, metanotal groove deeply impressed. Propodeum about 1.1 times higher than long, dorsal face of propodeum weakly convex and declining posteriorly, propodeum armed, posterodorsal corners each armed with a laminate triangular tooth, anterodorsal corner rounded and at same height as posterodorsal corner of promesonotum, declivity flat to slightly convex with thin lateral laminae. Propodeal lobes convex. Propodeal spiracle rounded and situated slightly above mid-height of sclerite by about half the diameter of the spiracle, and beyond mid-length of sclerite by about 1.5 times the diameter of the spiracle, distance from propodeal spiracle to posterodorsal corner of propodeum about three times the diameter of the spiracle (PSL 0.04-0.06), and distance to declivity same as the diameter of the spiracle. In dorsal view, anterior margin and sides of promesonotum rounded, narrowed posteriorly, slightly longer than wide; sides of propodeum straight.

Petiole longer than high (PTL 0.13-0.18, PTH 0.10-0.13) and with relatively long peduncle, ventral face medially convex. Combined outline of dorsal surface of peduncle and anterior face of node medially concave, posterior face of node slightly convex, anterodorsal corner convex, posterodorsal corner rounded, dorsum nearly rounded. Subpetiolar process is reduced to a small convexity, not longer than the diameter of the propodeal spiracle. Postpetiolar node rounded and lower than petiolar node. In dorsal view, postpetiolar node wider than petiolar node (PTW 0.08-0.10, PPW 0.11-0.15), and petiolar node as wide as long, anterior margin of petiole strongly convex, posterior margin rounded, anterior margin of postpetiole nearly straight, posterior margin rounded, sides convex in petiole and postpetiole, narrowed posteriorly in postpetiole.

Dorsal surface of mandibles, clypeus, supraclypeal area and frons smooth and shiny, with scattered piligerous punctae on head and mandibles. Gena and frontal lobes with longitudinal rugae. Mesosoma smooth and shiny, except for katepisternum (areolate), and metapleuron and propodeum (finely areolate). Petiole and ventral face of postpetiole areolate. In dorsal view, promesonotum, petiole, postpetiole and gaster smooth and shiny except for propodeum which is areolate.

Lateral margins of head with short appressed hairs, posterior margin with short subdecumbent hairs. Scapes with appressed hairs. Outer margin of mandibles with decumbent hairs. Mesosoma with short and long suberect to subdecumbent hairs. Petiole, postpetiole, tibia and gaster with short appressed hairs. Color yellowish ferruginous.

Distribution and biology.

Carebara mahafaly is known from two localities in the center of Madagascar (Figure 69). This species occurs in the rainforest and montane rainforest and was found at elevations of 780 m and 1300 m. Individuals and colonies were collected in sifted litter, leaf mold and rotten wood. Specimens were collected using maxi-Winkler and pitfall traps.

Comments.

Carebara mahafaly is endemic to the center of Madagascar. Other six species were recorded at the same localities: C. betsi , C. grandidieri , C. hainteny , C. jajoby , C. kabosy , and C. nosindambo . This species can be confused with C. salegi , especially in the shape of the head. C. mahafaly can be differentiated from C. salegi and other species by the following combination of characters: head slightly longer than wide, nearly subquadrate in full-face view, posterolateral corners rounded, lateral margins of head convex; propodeum with a pair of upwardly directed triangular teeth, and anterodorsal corner of petiole convex, additional to this C. salegi was recorded only in the north of Madagascar. C. mahafaly does not have intermediates in the major worker subcaste.

Additional material examined.

MADAGASCAR: Toamasina: Parc National de Zahamena, Onibe River, -17.75908, 48.85468, 780 m, rainforest, 21-23.ii.2009, (B.L. Fisher et al.).