Carebara coeca

Type specimens are noted as being collected from "in nest" but it is not stated where this nest was located. This cryptic note is the only known biological information.

Identification
Fernández (2004) - A member of the Carebara lignata species complex. The soldier is very similar to the Carebara tenua soldier but is smaller in size; neither eyes nor ocellae can be detected at 100X magnification; the mesosomal configuration differs somewhat (dorsal face of the propodeum sloping); and the petiole has a thick longitudinal keel ventrally. The minor worker is difficult to separate from other workers of the Carebara concinna complex. The propodeal spiracle is slightly bigger and is above, near the propodeal margin. Other aspects of this species and its neighbors are discussed under Carebara tenua.

There is variability in the ocellae and eyes, from totally eyeless (from which the species’ name derives) to samples with medial ocella present and eyes. Both ocellae and eyes exhibit a variable degree of development, from scars and dark spots to well-defined ocellae and eyes with several ommatidia.

In addition to this variability in ocellae and eyes, there is variation in the distance between the propodeal spiracle and the anterior border of the metapleural gland bulla. At one extreme, these structures touch one another, while at the other the spiracle is separated by a distance equivalent to half its diameter. The thorax sculpture is variable, from obvious to dilute and mixed with smooth, shining areas, but there is always some kind of longitudinal striation in the greater part of the pronotum and mesonotum.

In Carebara tenua the head sculpturing is less imprecise than in Carebara coeca, in which the ruguale are more raised from the tegument and cover the entire head. C. tenua does not have either the striation or the longitudinal rugulation of C. coeca and on the pronotal dorsum there are dense, dark, piligerous punctures. Only additional material, including both sexes, will allow resolution of whether C. tenua is distinct from C. coeca.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Colombia.

Nomenclature

 * . Carebara coeca Fernández, 2004a: 219, figs. 6A-C, 14 (s.w.q.m.) BRAZIL (Goiás, Bahia), COLOMBIA.
 * Status as species: Fernández & Serna, 2019: 822.

Worker
Major. (n=1) Holotype: HW 0.55; HL 0.78; SL 0.28; PW 0.33; WL 0.65; GL 0.75; TL 2.61; CI 71; SI 51.

Head rectangular, posterior border deeply semi circularly excised, sides straight, parallel. Mandible stout, masticatory border straight, forming an angle about 90° with basal border. Masticatory border with 5 stout teeth. Clypeus narrow, medial portion slightly concave. Frontal triangle well-defined. Frontal lobes somewhat continued posteriorly as short longitudinal rugulae. Scapes very short. Ocellae and eyes present, reduced or absent (see coments). In side view mesosoma flat, metanotum slightly higher, propodeum lower. Pronotal suture feebly impressed dorsally. Metanotum narrow. Dorsal face of propodeum sloping and then curving into the sloping face, without spines or angulations. Propodeal spiracle rounded, varying in closeness with metapleural gland bullae. Petiole with short peduncle, lateral swellings and strong thick lamellar median subpetiolar process. Postpetiole in posterior view campanuliform, ventrally with anterior carinae. Body smooth, somewhat shining. Head with a longitudinal rugulation. Anterior half of pronotum reticulated, otherwise pronotum and mesonotum with feeble longitudinal rugulation, sometimes with areas smooth and shining. Metapleura, propodeum petiole and postpetiole with fine reticulation. Pubescence very sparse over head, otherwise absent. Large hairs (about 0.13 mm) occur densely on head, several on promesonotum, petiole, postpetiole and gaster. Body light brown.

Minor Paratype: HW 0.23; HL 0.31; SL 0.16; PW 0.14; WL 0.28; GL 0.31; TL 1.10; CI 74; SI 70.

Head longer than wide. Posterior border concave, lateral sides faintly concave. Mandibles with 4 teeth. Median portion of clypeus nearly flat. In frontal oblique view, clypeal lateral carinae strongly narrowed posteriorly and between frontal lobes, then continued as frontal triangle. Scapes fail to reach the vertexal border in 1/2 of the head length. In side view, alitrunk slightly convex, interrupted by the deep metanotal groove. Dorsal face of propodeum curving in sloping face. Propodeal spiracle relatively large, circular, high and very close to the propodeal margin. Propodeal lobes reduced to narrow lamellae that reach the propodeal dorsum. Petiole with short peduncle, evenly continuous with the dorsal rounded node; petiolar node at midway of petiolar length. Subpetiolar process produced as anterior spine directed forward, spine normally not visible in mounted specimens. Postpetiole dorsally concave, lower than petiole. In dorsal view petiole longer than wide, postpetiole globose more or less as long as wide. In dorsal view anterior margin of first tergum straight. Body smooth and shining. Mandibles with several scattered punctures, head with scattered puncturations (except in the central longitudinal area), each punctum with a small hair. Anterior sides of head with very fine longitudinal striation. Sides of alitrunk (except pronotum), petiole, postpetiole and dorsum of petiolar peduncle with a faint to moderate reticulation. Short curved hairs (less than 0.03 mm) relatively abundant over body, especially on dorsum of head. Medium hairs (about 0.04 mm or longer): Four in the clypeus projecting forward, four on promesonotum (two anteriorly, two posteriorly), two on petiole, four on postpetiole. Apparently two on each side of head, near the occipital border. Whitish yellow.

Queen
HW 0.48; HL 0.60; SL 0.36; EL 0.14; WL 0.78; GL 0.85; TL 2.73; CI 80; SI 75.

Head longer than wide, the posterior margin concave, the sides more or less parallel, lightly narrowed posteriorly. Stout mandibles with five coarse teeth. Medial part of the clypeus concave and with two carinae that project anteriorly as angles which turn backwards and unite posteriorly at the level of the anterior margins of the antennal receptacles. Large, deep area surrounding tentorial pits, adjacent to the antennal sockets. Short scapes end at about the middle of the head. Large, multifaceted eyes. Three ocellae form a triangle, the posterior ones some way from vertex margin. Propodeal spiracle relatively large, circular, almost touching the bulla of the metapleural gland. In dorsal view, the petiole has a strongly-narrowed peduncle, and the node is wider than long. Petiole ventrally with an anterior spine, directed anteriorly. Dorsum of the head with longitudinal striations that disappear before the vertex, where there are a few disperse pits. Much of the mesosoma smooth and shining, except for the posterior medial part of the promesonotum, which has a few longitudinal rugulae. Short, appressed hairs on the head, mesosoma (except propodeum), petiole and post-petiole. Long, erect hairs over entire body, except the propodeum, where there are two. General color is light brown, except mandibular teeth, eyes and antennal club, which are darker.

Male
HW 0.64; HL 0.55; SL 0.11; EL 0.34; WL 1.19; GL 1.00; TL 3.24; CI 116; SI 17.

Head slightly wider than long. Mandibules with two teeth, the larger of which is apical, barely touching at the tips. Palps, 2,2 in situ. Eyes big, globular, with inferior parts bulging beyond the level of the clypeus. Anterior margin of clypeus more or less straight. Medial clypeus swollen. Very short scapes, the second antennal segment globose, the rest filiform. Three large ocellae form a cusp with the superior parts supassing above the level of the vertex. In the promesonotum there is a weak, complete, medial longitudinal line, two lateral, diagonal anterior lines, and two lateral, straight posterior lines. Wings with dense micropilosity, open marginal cell. Long petiole, with a long peduncle and a moderate node in the posterior part. Post-petiole about as long as wide, the anterior part narrowed. Large, erect hairs on the head, parts of the promesonotum, propodeum, and gaster; shorter over the rest of the body. Body light brown, head dark brown, eyes black.

Type Material
Holotype major worker. BRAZIL. Goias: Jatai, UFG, CCA, BR 364, km 192, in nest, 10 ene 2000, J. Diniz & C. Lásaro, deposited in. Paratypes. 1 major worker, 2 minor workers, same data, MZSP. BRAZIL. Bahia: 2 queens, 1 mayor, 1 male, 1 worker, Barrolandia, 16-23 jul 1994, S. Lacau, leg., CEPLAC.

References based on Global Ant Biodiversity Informatics

 * Lange D., W. D. Fernandes, J. Raizer, and R. Silvestre. 2008. Activity of hypogeic ants (Hymenoptera: Formicidae) in flooded and non-flooded forest patches in the Brazilian Pantanal. Sociobiology 51(3): 661-672.