Carebara tanana 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 tanana Azorsa & Fisher sp. n.

Holotype.

(major worker), MADAGASCAR, Antananarivo , Antaponimanadala I Non Protected Area, 6.59 km E Manalalondo, -19.25528, 47.1771, 1984 m, savannah grassland, 13-16.v.2010, (Andrianjaka Ravelomanana). Collection code ARA1053, (CASC: CASENT0211683). Paratypes: (3 major worker and 6 workers), with same data as holotype, 3 major workers (CASC: CASENT0211708, CASENT0211736, CASENT0211696), and 6 workers (CASC: CASENT0211714, CASENT0211777, CASENT0211709, CASENT0211697, CASENT0211737, CASENT0211684).

Diagnosis.

Antennae ten-segmented. Major: Head subrectangular, longer than wide, lateral margins straight and parallel, posterolateral corners rounded, posterior margin of head concave; combined outline of dorsal surface of peduncle and anterior face of node nearly straight; dorsum of propodeum flat and declining posteriorly, posterodorsal corner unarmed, nearly angulate; gaster with abundant subdecumbent to suberect hairs. Minor: Head nearly subquadrate, slightly longer than wide, lateral margins weakly convex, posterior margin weakly convex; combined outline of dorsal surface of peduncle and anterior face of node nearly straight; dorsum of propodeum nearly flat, declining posteriorly, posterodorsal corner unarmed, nearly angulate; gaster with subdecumbent or suberect hairs.

Description of major workers.

Measurements (n=1 (holotype)): HL 0.62; HW 0.48; SL 0.28; ML 0.15; EL 0.02; EM 0.18; HD 0.35; WL 0.54; PSL 0.06; PW 0.33; MFL 0.29; MFW 0.08; MTL 0.22, PTL 0.21; PNL 0.09; PTH 0.17; PTW 0.15; PPL 0.13; PPNL 0.13; PPH 0.13; PPW 0.20; GL 0.53; GW 0.43; CI 78; MI 24; SI 45; MLI 60; PPLI 60; PPI 133; PSI 12.

Head longer than wide (78), in full-face view weakly subrectangular, about 1.2 times longer than wide. Posterior margin of head medially concave, posterolateral corners rounded, lateral margins straight or weakly convex. Mandibles with five teeth. Anterior margin of clypeus nearly straight, and weakly convex laterally. Antennae with ten segments. Scapes short (HL 0.62, SL 0.28, SI 45) barely reaching cephalic midlength. Ocelli absent. Eyes present and short, consisting of only ommatidia (EL 0.02). Supraclypeal area short and triangular, not surpassing frontal carina.

In profile view, promesonotum high and convex, metanotal groove present and not deeply impressed. Propodeum lower than promesonotum, and about 1.3 times higher than long, dorsal face of propodeum flat and declining posteriorly, posterodorsal corners of propodeum unarmed, nearly angulate, declivity weakly convex, nearly flat. Propodeal lobes short and convex. Propodeal spiracle rounded and situated slightly above mid-height of sclerite, and beyond mid-length of sclerite by about half the diameter of the spiracle, distance from propodeal spiracle to posterodorsal corner of propodeum about same as the diameter of the spiracle (PSL 0.06), and distance to declivity less than the diameter of the spiracle. In dorsal view, promesonotum about as long as wide, anterior margin and sides rounded, slightly narrowed posteriorly; sides of propodeum nearly convex.

Petiole weakly longer than high (PTL 0.21, PTH 0.17) and with relatively short peduncle, ventral face weakly convex at center. Combined outline of dorsal surface of peduncle and anterior face of node straigth, posterior face of node weakly concave, anterodorsal corner convex, posterodorsal corner rounded, dorsum convex. Subpetiolar process produced as a small denticle, shorter than the diameter of the propodeal spiracle. Postpetiolar node weakly rounded and lower than petiolar node. In dorsal view, postpetiolar node wider than petiolar node (PTW 0.15, PPW 0.20) and petiolar node wider than long (PNL 0.09, PTW 0.15), anterior margin of petiole and postpetiole nearly straight, sides of petiole and postpetiole rounded.

Dorsal surface of mandibles, clypeus and median area of head smooth and shiny, with scattered piligerous punctae on head and mandibles. Head with longitudinal and parallel rugae, these joining near posterior margin of head, transverse rugae along posterior margin of head. Posterolateral portion of cephalic dorsum smooth and shiny. Mesosoma smooth and shiny, except for katepisternum (areolate), metapleuron (rugose and with longitudinal rugae), and anterior side of pronottum finely punctate. Petiole and ventral face of postpetiole (areolate). In dorsal view, mesosoma, petiole, postpetiole and gaster smooth and shiny.

Lateral and posterior margin of head with suberect to subdecumbent hairs. Scapes with decumbent hairs. Outer margin of mandibles with few and short appressed hairs. Mesosoma with short and long erect to subdecumbent hairs. Petiole and postpetiole with short decumbent hairs and long subdecumbent hairs. Tibia with appressed hairs. Gaster with abundant subdecumbent hairs. Color yellowish ferruginous.

Description of minor workers.

Measurements (n=1): HL 0.40; HW 0.34; SL 0.23; ML 0.10; EL 0.02; EM 0.11; HD 0.23; WL 0.41; PSL 0.03; PW 0.22; MFL 0.23; MFW 0.06; MTL 0.18, PTL 0.13; PNL 0.07; PTH 0.12; PTW 0.09; PPL 0.09; PPNL 0.08; PPH 0.08; PPW 0.13; GL 0.33; GW 0.28; CI 85; MI 25; SI 58; MLI 66; PPLI 69; PPI 136; PSI 10.

Head slightly longer than wide (CI 85), in full-face view nearly subquadrate, about 1.1 times longer than wide. Posterior margin of head slightly concave, posterolateral corners convex, lateral margins weakly convex. Mandibles with five teeth. Anterior margin of clypeus slightly straight, and laterally convex. Antennae with ten segments. Scape fails to reach posterior margin of head (HL 0.40, SL 0.23, SI 58). Eyes present, consisting of one ommatidium (EL 0.02). Supraclypeal area triangular but not well defined.

In profile view, promesonotum weakly convex, metanotal groove not well impressed. Propodeum about 1.2 times higher than long, dorsal face of propodeum slightly convex, declining posteriorly, posterodorsal corners unarmed or angulate, declivity nearly straight. Propodeal lobes short and convex. Propodeal spiracle rounded and situated above mid-height of sclerite, and beyond mid-length of sclerite by about half the diameter of the spiracle, distance from propodeal spiracle to posterodorsal corner of propodeum about the same as the diameter of the spiracle (PSL 0.03), and distance to declivity almost less than the diameter of the spiracle. In dorsal view, promesonotum about as long as wide, anterior margin rounded, sides nearly rounded, narrowed posteriorly; sides of propodeum straight.

Petiole weakly longer than high (PTL 0.13, PTH 0.12) and with a short peduncle, ventral face convex at center. Combined outine of dorsal surface of peduncle and anterior face of node straight, posterior face of node vertical and slightly concave, anterodorsal and posterodorsal corner rounded, dorsum convex. Subpetiolar process produced as a small denticle, same as the diameter of the propodeal spiracle. Postpetiolar node nearly rounded and lower than petiolar node. In dorsal view, postpetiolar node wider than petiolar node (PTW 0.09, PPW 0.13), and petiolar node wider than long (PNL 0.07, PTW 0.09), anterior and posterior margins of petiole and postpetiole straight, sides rounded in petiole and postpetiole.

Head, mandible and clypeus smooth and shiny with scattered piligerous punctae on head and mandibles. Gena and frontal lobes with short longitudinal rugae. Mesosoma smooth and shiny, except for katepisternum (areolate), and metapleuron (finely areolate combined with longitudinal rugae). Petiole and ventral face of postpetiole areolate. In dorsal view, mesosoma, petiole, postpetiole and gaster smooth and shiny.

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

Distribution and biology.

Carebara tanana is known only from the center of Madagascar (Figure 69). This species was found in the savannah grassland, at an elevation of 1984 m, in leaf mold and rotten wood. This species was collected using maxi-Winkler traps.

Comments.

Carebara tanana can be confused with C. tana due to the form of the head. However, the two can be separated easily by the following combination of characters: in profile view, posterodorsal corner of propodeum of C. tana armed and unarmed in C. tanana ; gaster with short and long and abundant suberect to subdecumbent hairs in C. tanana , while in C. tana the major worker has the gaster with short decumbent hairs and long subdecumbent or suberect hairs, and the minor worker with abundant subdecumbent and decumbent hairs, and sparse suberect hairs. Additional to this, C. tanana is known only from the center of Madagascar, while C. tana is known from the north of Madagascar. Only other two species were collected at the same area: C. grandidieri , and C. nosindambo .

C. tanana does not have intermediates in the major worker subcaste.