Carebara sampi 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 sampi Azorsa & Fisher sp. n.

Holotype.

(major worker), MADAGASCAR, Fianarantsoa , Parc National d’Isalo, Sahanafa River, 29.2 km 351° N Ranohira, -22.31333, 45.29167, 500 m, gallery forest, 10-13.ii.2003, (Fisher, Griswold et al.). Collection code BLF07651, (CASC: CASENT0031265). Paratypes: (9 major worker and 29 workers), with same data as holotype, 8 major workers (BMNH: CASENT0031260, CASC: CASENT0031268, CASENT0030374, CASENT0031267, CASENT0030481, CASENT0030407, CASENT0030441, MCZ: CASENT0030377), and 29 workers (BMNH: CASENT0030403, CASC: CASENT0030456, CASENT0031234, CASENT0031262, CASENT0031216, CASENT0030486, CASENT0031215, CASENT0031274, CASENT0030415, CASENT0030444, CASENT0030490, CASENT0030379, CASENT0030413, CASENT0030398, CASENT0030402, CASENT0030406, CASENT0030437, CASENT0030414, CASENT0030518, CASENT0030447, CASENT0030401, CASENT0030420, CASENT0031259, CASENT0030400, CASENT0031261, CASENT0030443, MCZ: CASENT0030409, MHNG: CASENT0030425, NHMB: CASENT0031272). 1 major worker with same data as holotype and collection code BLF07653, (CASC: CASENT0049730).

Diagnosis.

Antennae ten-segmented. Major: Head subrectangular, longer than wide, narrowed posteriorly, lateral margins slightly convex, posterolateral corners well developed, posterior margin of head deeply concave; dorsum of propodeum flat, posterodorsal corner with a pair of small triangular teeth; gaster with short appressed hairs, and longer, sparse suberect or subdecumbent hairs. Minor: Head subquadrate, slightly longer than wide, narrowed anteriorly, posterior margin of head nearly straight, lateral margins convex; dorsum of propodeum nearly flat, anterodorsal corner slightly convex, posterodorsal corner with a pair of triangular teeth; combined outline of dorsal surface of peduncle and anterior face of node nearly concave, and posterior face convex; gaster with short appressed hairs and dispersed and longer suberect or subdecumbent hairs.

Description of major workers.

Measurements (n=13): HL 0.57-0.92 (0.82); HW 0.49-0.72 (0.64); SL 0.26-0.35 (0.31); ML 0.12-0.24 (0.21); EL 0.01-0.03 (0.02); EM 0.16-0.28 (0.25); HD 0.32-0.52 (0.45); WL 0.51-0.85 (0.70); PSL 0.05-0.11 (0.08); PW 0.30-0.47 (0.41); MFL 0.29-0.52 (0.41); MFW 0.07-0.12 (0.10); MTL 0.21-0.40 (0.30); PTL 0.19-0.32 (0.27); PNL 0.09-0.14 (0.12); PTH 0.14-0.24 (0.20); PTW 0.12-0.22 (0.17); PPL 0.11-0.22 (0.18); PPNL 0.11-0.20 (0.16); PPH 0.12-0.23 (0.18); PPW 0.18-0.32 (0.25); GL 0.43-1.10 (0.78); GW 0.39-0.82 (0.58); CI 76-86 (78); MI 21-26 (26); SI 37-46 (38); MLI 59-74 (64); PPLI 58-70 (67); PPI 131-152 (147); PSI 10-16 (13).

Head longer than wide (CI 76-86), in full-face view subrectangular, about 1.3 times longer than wide, slightly narrowed on the top. Posterior margin of head deeply concave in the middle, posterolateral corners well developed, rounded and narrowed forward, lateral margins slightly convex. Mandibles with six teeth. Anterior margin of clypeus slightly concave, and laterally convex. Antennae with ten segments. Scapes short (HL 0.57-0.92, SL 0.26-0.35, SI 37-46). Ocelli present or absent. Eyes present, consisting of two or three ommatidia (EL 0.01-0.03). Supraclypeal area triangular and well defined.

In profile view, posterolateral corner of head with a small angulate tooth resembling a horn. Promesonotum high and nearly rounded, metanotal groove deeply impressed. Propodeum lower than promesonotum, and about 1.4 times higher than long, dorsal face of propodeum flat and declining posteriorly, posterodorsal corners of propodeum each armed with a small triangular tooth, declivity concave, nearly flat with thin lateral laminae. Propodeal lobes convex. 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, (close to mid-height and mid-length in larger major workers), distance from propodeal spiracle to posterodorsal corner of propodeum about twice the diameter of the spiracle (PSL 0.05-0.11), and distance to declivity same as the diameter of the spiracle. In dorsal view, promesonotum about as long as wide, anterior and posterior margins, as well as sides rounded; sides of propodeum straight.

Petiole longer than high (PTL 0.19-0.32, PTH 0.14-0.24) and with relatively long peduncle, ventral face weakly convex in the middle. Combined outline of dorsal surface of peduncle and anterior face of node slightly concave, posterior face of node vertical and weakly concave, anterodorsal corner convex, posterodorsal corner rounded, dorsum nearly rounded. Subpetiolar process produced as a small denticle, almost as large as the diameter of the propodeal spiracle. Postpetiolar node rounded and slightly lower than petiolar node. In dorsal view, postpetiolar node wider than petiolar node (PTW 0.12-0.22, PPW 0.18-0.32) and petiolar node wider than long (PNL 0.09-0.14, PTW 0.12-0.22), anterior and posterior margins of petiole and postpetiole nearly straight, sides of petiole and postpetiole nearly rounded.

Dorsal surface of mandibles, clypeus and frons smooth and shiny with scattered piligerous punctae on head and mandibles. Head with longitudinal rugae directed to posterolateral corners of head, transverse rugae, and reticulate on median area of posterior margin of head, followed by short longitudinal rugae. Mesosoma smooth and shiny, except for katepisternum and propodeum (areolate), and metapleuron (areolate-rugose and with longitudinal rugae). Petiole, ventral face and sides of postpetiole areolate. In dorsal view, promesonotum, postpetiole and gaster smooth and shiny; propodeum and petiole areolate.

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

Description of minor workers.

Measurements (n=11): HL 0.32-0.40; HW 0.27-0.34; SL 0.20-0.26; ML 0.08-0.10; EL 0.01-0.02; EM 0.09-0.11; HD 0.20-0.22; WL 0.32-0.42; PSL 0.03-0.05; PW 0.10-0.21; MFL 0.20-0.26; MFW 0.05-0.07; MTL 0.14-0.20; PTL 0.11-0.15; PNL 0.06-0.08; PTH 0.09-0.12; PTW 0.08-0.10; PPL 0.06-0.09; PPNL 0.06-0.09; PPH 0.07-0.09; PPW 0.10-0.14; GL 0.26-0.48; GW 0.20-0.35; CI 83-91; MI 22-29; SI 61-68; MLI 69-81; PPLI 57-69; PPI 125-150; PSI 9-13.

Head longer than wide (CI 83-91), 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 concave, and laterally angulate, almost triangular. Antennae with ten segments. Scape fails to reach posterior margin of head (HL 0.32-0.40, SL 0.20-0.26, SI 61-81). Eyes present, consisting of two ommatidia (EL 0.01-0.02). Supraclypeal area short and triangular, but poorly defined.

In profile, promesonotum weakly convex, nearly flat, metanotal groove deeply impressed. Propodeum 1.3 times higher than long, dorsal face of propodeum flat and barely declining posteriorly, posterodorsal corners of propodeum each armed with a triangular tooth, anterodorsal corner rounded, declivity concave with thin lateral laminae. Propodeal lobes convex. Propodeal spiracle rounded and situated above mid-height of sclerite by about half the diameter of the spiracle, and beyond mid-length of sclerite by about two times the diameter of the spiracle, distance from propodeal spiracle to posterodorsal corner of propodeum about twice the diameter of the spiracle (PSL 0.03-0.05), and distance to declivity about 0.5 times the diameter of the spiracle. In dorsal view, promesonotum almost as longer as wide, anterior margin rounded, sides convex and narrowed posteriorly; sides of propodeum convex.

Petiole longer than high (PTL 0.11-0.15, PTH 0.09-0.12) and with relatively long peduncle, ventral face medially convex. Combined outline of dorsal surface of peduncle and anterior face of node slightly concave in the middle, nearly straight, posterior face of node convex, anterodorsal and posterodorsal corner rounded, dorsum nearly rounded. Subpetiolar process produced as a small denticle, almost as large as the diameter of the propodeal spiracle. Postpetiolar node convex and slightly lower than petiolar node. In dorsal view, postpetiolar node wider than petiolar node (PTW 0.08-0.10, PPW 0.10-0.14), and petiolar node slightly wider than long (PNL 0.06-0.08, PTW 0.08-0.10), anterior and posterior margins of petiole weakly convex, and straight in postpetiole, sides rounded in petiole and 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), metapleuron (finely areolate). Petiole and ventral face of postpetiole areolate-rugose. In dorsal view, promesonotum, postpetiole and gaster smooth and shiny; propodeum and petiole areolate.

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

Distribution and biology.

Carebara sampi is known from south and southwestern Madagascar (Figure 69) where it was found in gallery forest, tropical dry forest, and gallery forest on sandy soil, at elevations ranging from 20 m to 525 m. This species was found in the following microhabitats: rotten logs, leaf mold, rotten wood, and in semi-deciduous vegetation. Specimens were collected using maxi-Winkler traps.

Comments.

Carebara sampi can be confused with C. lova but can be separated by the distance from the posterior border of propodeal spiracle to declivity, which is less than two times the diameter of the spiracle in C. sampi , while is same as or less than the diamater of the spiracle in C. lova . C. sampi is distributed from south and southwestern Madagascar, while C. lova is located in the northwestern of Madagascar. Other five species were recorded at the same area: C. bara , C. dota , C. grandidieri , C. hiragasy , and C. omasi .

C. sampi have three intermediates in the major worker subcaste (Figure 63). The posterolateral corner of head in intermediate 1 is narrowed posteriorly, and the posterior margin of the head is medially concave in all intermediates. Eyes are small and reduced to one ommatidium in all intermediates. Ocelli are absent in intermediate 1, slightly present in intermediate 2, present and well developed in intermediate 3 (one ocellus). Reduced flight sclerites are present in intermediate 3 and absent in intermediate 1 and 2. The dorsum of the mesosoma is convex anteriorly and gradually slopes to the declivity in intermediate 3, while in intermediate 1 and 2 the dorsum of the mesosoma is nearly rounded anteriorly, the propodeum is below the promesonotum. The propodeum is armed with a pair of small triangular teeth in all intermediates. The form of the petiole and postpetiole is the same among the intermediates. The sculpture is the same in all intermediates, with longitudinal rugae on the head with the frontal area smooth and shiny. The pilosity on the head and body follow the same pattern, except for intermediate 3, which has more abundant appressed hairs on the gaster than intermediates 1 and 2.

Additional material examined.

MADAGASCAR: Toliara . Réserve Privé Berenty, Forêt de Malaza, Mandraré River, 8.6 km 314° NW Amboasary, -25.00778, 46.306, 40 m, gallery forest, 6.ii.2002, (Fisher, Griswold et al.); Toliara , Forêt de Mite, 20.7 km 29° WNW Tongobory, -23.52417, 44.12133, 75 m, gallery forest, 27.ii.-3.iii.2002, (Fisher, Griswold et al.); Toliara , Réserve Privé Berenty, Forêt de Bealoka, Mandraré River, 14.6 km 329° NNW Amboasary, -24.95694, 46.2715, 35 m, gallery forest, 3-8.ii.2002, (Fisher, Griswold et al.); Toliara , Fiherenana, -23.17698, 43.96142, gallery forest, 18-19.viii.2003, (Frontier Wilderness Project); Toliara , Beza-Mahafaly, 27 km E Betioky, -23.65, 44.63333, 135 m, tropical dry forest, 23.iv.1997, (B.L. Fisher); Toliara , Makay Mts., -21.21836, 45.3106, 510 m, gallery forest on sandy soil, 24-27.xi.2010, (B.L. Fisher et al.); Toliara , Makay Mts., -21.20978, 45.34184, 525 m, gallery forest on sandy soil, 27.xi-2.xii.2010, (B.L. Fisher et al.); Toliara , Makay, -21.22283, 45.32453, 525 m, gallery forest, 11.i.2010, (J.M. Bichain); Toliara , Makay, -21.22283, 45.32453, 525 m, gallery forest, 9.i.2010, (J.M. Bichain).