Carebara tana 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 tana Azorsa & Fisher sp. n.

Holotype.

(major worker), MADAGASCAR, Antsiranana , Parc National Montagne d’Ambre, 3.6 km 235° SW Joffreville, -12.53444, 49.1795, 925 m, montane rainforest, 20-26.i.2001, (Fisher, Griswold et al.). Collection code BLF02564, (CASC: CASENT0437707). Paratypes: (3 major worker and 9 workers), with same data as holotype, 3 major workers (CASC: CASENT0438090, CASENT0437819, CASENT0437704), and 9 workers (BMNH: CASENT0437708, CASC: CASENT0438034, CASENT0438095, CASENT0438096, CASENT0438088, CASENT0438109, MCZ: CASENT0437825, MHNG: CASENT0437830, NHMB: CASENT0438076).

Diagnosis.

Antennae ten-segmented. Major: Head subrectangular, longer than wide, lateral margins straight and parallel, posterolateral corners rounded, posterior margin of head concave; dorsum of propodeum flat and declining posteriorly, posterodorsal corner with a pair of triangular teeth; gaster with short decumbent hairs and sparse and longer subdecumbent hairs. Minor: Head nearly subquadrate, slightly longer than wide, lateral margins weakly convex, posterior margin weakly convex; dorsum of propodeum nearly flat, posterodorsal corner with a pair of small triangular teeth; gaster with abundant decumbent hairs and sparse suberect to subdecumbent hairs.

Description of major workers.

Measurements (n=5): HL 0.61-0.65 (0.65); HW 0.47-0.51 (0.49); SL 0.23-0.26 (0.25); ML 0.12-0.14 (0.13); EL 0.02-0.03 (0.02); EM 0.14-0.20 (0.18); HD 0.29-0.33 (0.33); WL 0.50-0.54 (0.53); PSL 0.05-0.07 (0.06); PW 0.31-0.35 (0.32); MFL 0.29-0.32 (0.32); MFW 0.08-0.09 (0.08); MTL 0.20-0.27 (0.20), PTL 0.20-0.24 (0.20); PNL 0.11-0.12 (0.11); PTH 0.14-0.16 (0.16); PTW 0.13-0.15 (0.14); PPL 0.12-0.13 (0.12); PPNL 0.11-0.12 (0.12); PPH 0.11-0.12 (0.12); PPW 0.16-0.18 (0.18); GL 0.43-0.51 (0.51); GW 0.36-0.41 (0.41); CI 75-79 (75); MI 19-22 (20); SI 38-40 (38); MLI 60-65 (65); PPLI 50-65 (60); PPI 120-129 (129); PSI 10-15 (12).

Head longer than wide (CI 75-79), in full-face view nearly subrectangular, about 1.3 times longer than wide. Posterior margin of head medially concave, posterolateral corners rounded, lateral margins straight and parallel. Mandibles with five teeth. Anterior margin of clypeus slightly concave, and laterally convex. Antennae with ten segments. Scapes short (HL 0.61-0.65, SL 0.23-0.26, SI 38-40) not surpassing cephalic midlength. Ocelli absent. Eyes present, consisting of two or three ommatidia (EL 0.02-0.03). Supraclypeal area short and triangular.

In profile view, promesonotum high and nearly rounded, metanotal groove deeply impressed. Propodeum lower than promesonotum, and about 1.7 times higher than long, dorsal face of propodeum flat and declining posteriorly, posterodorsal corners of propodeum each armed with a triangular tooth, declivity concave, nearly flat, with thin lateral laminae. Propodeal lobes triangular. 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 the diameter of the spiracle, distance from propodeal spiracle to posterodorsal corner of propodeum about 2.5 times the diameter of the spiracle (PSL 0.05-0.07), and distance to declivity same as 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 straight.

Petiole longer than high (PTL 0.20-0.24, PTH 0.14-0.16) and with relatively long peduncle, ventral face weakly convex at center. Combined outline of dorsal surface of peduncle and anterior face of node concave, posterior face of node weakly convex, anterodorsal corner convex, posterodorsal corner rounded, dorsum convex. Subpetiolar process produced as a small denticle, almost as large as the diameter of the propodeal spiracle. Postpetiolar node convex and lower than petiolar node. In dorsal view, postpetiolar node wider than petiolar node (PTW 0.13-0.15, PPW 0.16-0.18) and petiolar node wider than long (PNL 0.11-0.12, PTW 0.13-0.15), anterior margin of petiole convex, posterior margin weakly concave, anterior and posterior margins of postpetiole straight, sides of petiole rounded, and sides of postpetiole narrowed posteriorly and convex.

Dorsal surface of mandibles, clypeus and frons 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 with longitudinal rugae. Mesosoma smooth and shiny, except for katepisternum (areolate), metapleuron (rugose and with longitudinal rugae), and dorsum of propodeum (finely areolate). Petiole and ventral face of postpetiole (areolate). In dorsal view, promesonotum, petiole, postpetiole and gaster smooth and shiny.

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

Description of minor workers.

Measurements (n=9): HL 0.35-0.38; HW 0.31-0.33; SL 0.21-0.23; ML 0.09-0.10; EL 0.01; EM 0.10-0.11; HD 0.21-0.23; WL 0.35-0.39; PSL 0.03-0.04; PW 0.19-0.21; MFL 0.22-0.24; MFW 0.05, MTL 0.16-0.18; PTL 0.12-0.15; PNL 0.06-0.07; PTH 0.10-0.11; PTW 0.07-0.08; PPL 0.07-0.08; PPNL 0.06-0.07; PPH 0.07-0.08; PPW 0.10-0.13; GL 0.31-0.35; GW 0.21-0.28; CI 86-89; MI 24-27; SI 57-63; MLI 69-75; PPLI 50-58; PPI 125-163; PSI 9-13.

Head slightly longer than wide (CI 86-89), in full-face view nearly subquadrate, about 1.1 times longer than wide. Posterior margin of head slightly concave, posterolateral corners rounded, lateral margins weakly convex. Mandibles with five teeth. Anterior margin of clypeus slightly concave in the middle, and laterally angulate. Antennae with ten segments. Scape fails to reach posterior margin of head (HL 0.35-0.38, SL 0.21-0.23, SI 57-63). 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 1.1 times higher than long, dorsal face of propodeum slightly concave in the middle, nearly flat, declining posteriorly, posterodorsal corners each armed with a triangular tooth, anterodorsal corner rounded and higher than posterodorsal corner of promesonotum, declivity concave with thin lateral laminae. Propodeal lobes triangular. 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 two times the diameter of the spiracle, distance from propodeal spiracle to posterodorsal corner of propodeum about 2.5 times the diameter of the spiracle (PSL 0.03-0.04), and distance to declivity almost half the diameter of the spiracle. In dorsal view, promesonotum about as long as wide, anterior margin rounded, sides convex, narrowed posteriorly; sides of propodeum straight.

Petiole longer than high (PTL 0.12-0.15, PTH 0.10-0.11) and with a short peduncle, ventral face convex at center. Combined outine of dorsal surface of peduncle and anterior face of node slightly concave, posterior face of node vertical and slightly convex, anterodorsal corner convex, posterodorsal corner rounded, dorsum convex. Subpetiolar process produced as a small denticle. Postpetiolar node nearly rounded and lower than petiolar node. In dorsal view, postpetiolar node wider than petiolar node (PTW 0.07-0.08, PPW 0.10-0.13), and petiolar node almost as broad as long (PNL 0.06-0.07, PTW 0.07-0.08), anterior and posterior margins of petiole convex, anterior and posterior margins of 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). Petiole and ventral face of postpetiole areolate. In dorsal view, mesosoma, petiole, postpetiole and gaster smooth and shiny.

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

Distribution and biology.

Carebara tana is known only from the north of Madagascar (Figure 69). This species was found in montane rainforest, at an elevation of 925 m, in leaf litter, leaf mold and rotten wood. This species was collected using maxi-Winkler traps.

Comments.

Carebara tana can be confused with C. demeter due to the form of the head. However, the two can be separated by the following combination of characters: in full-face view, the head sculpture of C. tana has nearly longitudinal and parallel rugae, while C. demeter has irregular longitudinal rugae, and is reticulate near the posterior margin of the head; the frontal area is smooth and shiny in C. tana ; the petiolar node of C. tana is thicker than C. demeter ; the combined outline of dorsal surface of peduncle and anterior face of node is nearly flat in C. demeter , and slightly concave in C. tana ; the anteroventral corner has a well-developed triangular tooth in C. demeter , and a small, angulate, or triangular tooth in C. tana ; the anterodorsal corner of the petiole is convex in C. tana , and rounded in C. demeter , the posterodorsal corner is convex in C. demeter , and slightly concave in C. tana . C. tana is endemic to the north of Madagascar and other six species were recorded at the same area: C. bara , C. berivelo , C. grandidieri , C. kabosy , C. malagasy , and C. vazimba .

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