Carebara salegi 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 salegi Azorsa & Fisher sp. n.

Holotype.

(major worker), MADAGASCAR, Antsiranana , Forêt d’Orangea, 3.6 km 128° SE Remena, -12.25889, 49.37467, 90 m, littoral rainforest, 22-28.ii.2001, (Fisher, Griswold et al.). Collection code BLF03200, (CASC: CASENT0438150). Paratypes: (22 workers), with same data as holotype (BMNH: CASENT0438112, CASC: CASENT0438113, CASENT0438115, CASENT0438132, CASENT0438142, CASENT0438149, CASENT0438120, CASENT0438122, CASENT0438189, CASENT0438121, CASENT0438148, CASENT0438152, CASENT0438119, CASENT0438144, CASENT0438126, CASENT0438110, CASENT0438117, CASENT0438151, CASENT0438186, MCZ: CASENT0438124, MHNG: CASENT0438180, NHMB: CASENT0438113).

Diagnosis.

Antennae ten-segmented. Major: Head nearly subrectangular, longer than wide, narrowed anteriorly, lateral margins of head convex; dorsum of propodeum nearly flat, posterodorsal corner with a pair of small triangular teeth; combined outline of dorsal surface of peduncle and anterior face of node concave, posterior face vertical and straight; gaster with abundant, short decumbent hairs, and long subdecumbent hairs. Minor: Head nearly subquadrate, slightly longer than wide, narrowed anteriorly, posterior margin of head nearly straight; dorsum of propodeum nearly flat, propodeum armed with a pair of short triangular teeth; combined outline of dorsal surface of peduncle and anterior face of node concave, posterior face convex; gaster with abundant, short decumbent hairs, and sparse, long subdecumbent hairs.

Description of major workers.

Measurements (n=1 (holotype)): HL 0.55; HW 0.46; SL 0.24; ML 0.11; EL 0.02; EM 0.15; HD 0.30; WL 0.47; PSL 0.05; PW 0.30; MFL 0.29; MFW 0.08, MTL 0.22; PTL 0.18; PNL 0.09; PTH 0.14; PTW 0.13; PPL 0.12; PPNL 0.11; PPH 0.11; PPW 0.17; GL0.42; GW 0.36; CI 84; MI 20; SI 44; MLI 63; PPLI 67; PPI 131; PSI 11.

Head longer than wide (CI 84), in full-face view nearly subrectangular, about 1.2 times longer tan wide, slightly narrowed anteriorly. Posterior margin of head medially concave, posterolateral corners rounded, lateral margins convex. Mandibles with six teeth. Anterior margin of clypeus slightly concave in the middle, nearly straight, and laterally convex. Antennae with ten segments. Scapes short (HL 0.55. SL 0.24, SI 44). Ocelli absent. Eyes present, consisiting of three ommatidia (EL 0.02). Supraclypeal area with a longitudinal strip, barely surpassing frontal carina.

In profile view, posterolateral corner of head with a small angulate tooth resembling a horn. Promesonotum high and convex, metanotal groove deeply impressed. Propodeum lower than promesonotum, and about 1.5 times higher than long, dorsal face of propodeum flat and declining posteriorly, posterodorsal corners of propodeum each armed with a triangular tooth, anterodorsal corner convex, declivity of propodeum concave with thin lateral laminae. Propodeal lobes triangular. Propodeal spiracle rounded and situated slightly above mid-height of sclerite by about less tan half the diameter of the spiracle, and beyond mid-length of sclerite by about the diameter of the spiracle, distance from propodeal spiracle to posterodrosal corner of propodeum about 1.8 times the diameter of the spiracle (PSL 0.05), and distance to declivity about 0.5 times the diameter of the spiracle. In dorsal view, promesonotum about as long as wide, anterior margin and sides rounded; sides of propodeum weakly convex.

Petiole longer than high (PTL 0.18, PTH 0.14) and with relatively long peduncle, ventral face weakly convex in the middle. Combined outline of dorsal surface of peduncle and anterior face of node concave, posterior face of node vertical and straight, anterodorsal corner convex, posterodorsal corner rounded, dorsum nearly rounded. Subpetiolar process produced as a small denticle, slightly smaller than the diameter of the propodeal spiracle. Postpetiolar node convex and lower than petiolar node. In dorsal view, postpetiolar node wider than petiolar node (PTW 0.13, PPW 0.17) and petiolar node wider than long (PNL 0.09, PTW 0.13), anterior margin of petiole convex, posterior margin weakly concave, anterior and posterior margins of postpetiole straight, sides rounded in petiole and postpetiole.

Dorsal surface of mandibles, clypeus and frons smooth and shiny with scattered piligerous punctae on head and mandibles. Head with finely longitudinal rugae except for middle area of head, rugoreticulate close to posterior margin of head. Posterolateral portion of cephalic dorsum smooth and shiny. Mesosoma smooth and shiny, except for katepisternum and propodeum (areolate), and metapleuron (areolate and with longitudinal rugae). Petiole and ventral face of postpetiole areolate. In dorsal view, promesonotum, postpetiole and gaster smooth and shiny; propodeum and petiole areolate.

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

Description of minor workers.

Measurements (n=8): HL 0.34-0.38; HW 0.30-0.33; SL 0.21-0.24; ML 0.08-0.09; EL 0.01; EM 0.09-0.11; HD 0.20-0.22; WL 0.35-0.38; PSL 0.02-0.04; PW 0.19-0.22; MFL 0.21-0.25; MFW 0.05-0.06; MTL 0.16-0.19; PTL 0.13-0.14; PNL 0.07-0.08; PTH 0.10-0.11; PTW 0.07-0.09; PPL 0.08-0.09; PPNL 0.07-0.08; PPH 0.07-0.08; PPW 0.11-0.12; GL 0.29-0.40; GW 0.22-0.28; CI 85-92; MI 21-26; SI 61-67; MLI 68-78; PPLI 57-69; PPI 129-171; PSI 5-13.

Head longer than wide (CI 85-92), in full-face view nearly subquadrate, about 1.1 times longer than wide, narrowed anteriorly. Posterior margin of head nearly straight, weakly concave, posterolateral corners rounded, lateral margins convex. Mandibles with five teeth. Anterior margin of clypeus nearly straight, and laterally angulate, almost triangular. Antennae with ten segments. Scape fails to reach the posterior margin of head (HL 0.34-0.38, SL 0.21-0.24, SI 61-67). Eyes present, consisting of one ommatidium (EL 0.01). Supraclypeal area triangular but not well defined.

In profile view, promesonotum weakly convex, metanotal groove deeply impressed. Propodeum about 1.2 times higher than long, dorsal face of propodeum nearly flat, and barely declining posteriorly, posterodorsal corner usually unarmed but when armed, posterodorsal corners each armed with a small triangular tooth, declivity nearly flat with thin lateral laminae. Propodeal lobes triangular. Propodeal spiracle nearly oval 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 twice the diameter of the spiracle (PSL 0.02-0.04), and distance to declivity same as the diameter of the spiracle. In dorsal view, promesonotum about 1.1 times longer than wide, anterior margin and sides rounded, narrowed posteriorly; sides of propodeum flat.

Petiole longer than high (PTL 0.13-0.14, PTH 0.10-0.11) and with relatively short peduncle, ventral face convex. Combined outline of dorsal surface of peduncle and anterior face of node concave, posterior face of node convex, anterodorsal and posterodorsal corner rounded, dorsum nearly rounded. Subpetiolar process produced as a small denticle. Postpetiolar node convex and lower than petiolar node. In dorsal view, postpetiolar node wider than petiolar node (PTW 0.07-0.09, PPW 0.11-0.12), and petiolar node as wide as long (PNL 0.07-0.08, PTW 0.07-0.09), anterior and posterior margins of petiole convex, and weakly concave in postpetiole, sides convex in petiole and rounded in postpetiole.

Dorsal surface of head, mandibles 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 and propodeum (areolate), and metapleuron (longitudinally and finely areolate-rugose). Petiole and ventral face of postpetiole areolate. In dorsal view, promesonotum, petiole, postpetiole and gaster smooth and shiny; propodeum areolate.

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

Distribution and biology.

Carebara salegi is known only from the north of Madagascar (Figure 69) and occurs in the littoral rainforest, at an elevation of 90 m. Specimens were collected using maxi-Winkler traps and found in leaf litter, leaf mold and rotten wood.

Comments.

Carebara salegi is endemic to the north of Madagascar, and only one major worker of this species has been collected. Other six species were recorded at the same area: C. bara , C. berivelo , C. grandidieri , C. kabosy , C. malagasy , and C. tana .

C. salegi may be confused with C. mahafaly because of the form of the head. However, the posterior margin of the head of C. mahafaly is more concave than C. salegi , and the lateral margins of the head of C. mahafaly are more convex. The promesonotum is nearly rounded in C. mahafaly and convex in C. salegi . The posterodorsal corners of propodeum in C. mahafaly have a pair of triangular teeth directed slightly upward. In C. salegi the propodeum is armed with a pair of small triangular teeth that are not directed upward. The anterodorsal corner of the petiole in C. mahafaly is nearly rounded while C. salegi is convex. The gaster has short appressed hairs in C. mahafaly , and short decumbent hairs in C. salegi . In the workers, the main difference between these two species is the form of the propodeum, which is similar to the major worker subcaste.

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