Blepharidatta Wheeler, 1913

Brandão, Carlos Roberto F., Feitosa, Rodrigo M. & Diniz, Jorge L. M., 2015, Taxonomic revision of the Neotropical Myrmicinae ant genus Blepharidatta Wheeler, Zootaxa 4012 (1) : 35-40

Blepharidatta Wheeler, 1913

( Figures 1–9)

Blepharidatta Wheeler , W. M. 1915: 484, workers (type-species: Blepharidatta brasiliensis , by monotypy; Blepharidatta in Attini); Gallardo, 1916: 318 (misidentification); Forel, 1917: 247 ( Blepharidatta in Myrmicinae ); Wheeler, W. M. 1922: 66, 376, 668 (habits; Blepharidatta in key to Myrmicinae genera); Emery, 1924: 315 (diagnosis; catalogue), 316 (genus characters; systematic position in Dacetini and distribution); Donisthorpe, 1943: 628 ( Blepharidatta in Dacetini); Brown, 1953: 4: (systematic position in Ochetomyrmecini); Kusnezov, 1964: 59; Kempf, 1967: 358 (description of B. conops systematic position); Kempf, 1972: 37 (catalogue); Brown, 1973: 179 ( Blepharidatta as provisional junior synonym of Ochetomyrmex Mayr ); Kempf, 1975: 369 ( Blepharidatta as a valid genus; first description of male); Brandão, 1991 (catalogue); Jaffé, 1993: 12; Wheeler, G. C. & Wheeler, J. 1991: 132 (first description of larvae; Blepharidatta in Blepharidattini); Bolton, 1995a: 80 (census); Bolton, 1995b: 1048 (catalogue); Diniz et al., 1998 (biology); Rabeling et al., 2006 (biology); Pereira et al., 2014 (biology); Ward et al. 2015: 17 ( Blepharidatta in Attini); Bolton, 2015 (catalogue).

Workers. Total length varying from 2 to 5 mm. Body yellowish to dark castaneous or dark reddish brown. Subopaque integument with more or less bright gaster. Body densely sculptured. Margins of frontal carina with regularly arranged setiform hairs. Head in full-face view subrectangular, longer than broad, lateral margins slightly diverging caudad, posterior margin straight to slightly convex. Masticatory margin of mandible with apical tooth and 3–4 subapical teeth. Labrum bilobed. Anterior clypeal margin convex in frontal view. Frontal area triangular. Frontal lobe short anteriorly, not covering posterior margin of clypeus in frontal view. Compound eye large, located anterior to the longitudinal mid-length of head, bulging conspicuously from lateral margin in full-face view, sometimes conical, always set ventrally to antennal scrobe. Antennal scape apex almost reaching occipital corner when laid back inside scrobe; scrobe closed at vertex; regularly arranged setiform hairs present on scrobe dorsal margins. Antennal club 2-segmented, with apical segments distinctly longer than wide. Post occipital carina always reaching the latero-dorsal corner of head.

Pronotum with ventro-lateral angle always with projecting blunt tooth, sometimes bilobed and foliaceous. Anterior margin of katepisternum projects as triangular, sometimes translucid flange, in some species this structure is duplicated in twin lobes, one anterior to the other. Bulla of metapleural gland indistinct. Propodeum with pair of thin generally diverging spines, which can be extremely large. Petiole elongate, circa three times as long as wide, with an inconspicuous node. Gaster ellipsoidal with compressed sides.

Sting apparatus ( Figs 6–8). Spiracular plate sub-quadrate or sub-rectangular; median connection with completely sclerotized margin; spiracle at middle of plate or closer to posterior margin. Dorsal cleft absent. Anterior apodeme narrow but slightly swollen antero-ventrally. Quadrate plate with ventral width approximately equal to dorsal width. Dorsal margin concave medially. Antero-dorsal corner with a well-developed projection. Posterior margin entire. Anal plate with sclerotized anal arch, perimeter well defined. Sensillar insertion at margin. Trichodea sensilla present. Posterior arm of oblong plate lacking ventral margin. Postincision developed. Gonostylus one-segmented. Terminal sensilla with dorso-terminal hair. Basiconic sensilla absent. Triangular plate short, its length less than twice its width. Lancets with a pair of valves and one barbule. Distal half well sclerotized and sharp, probably non-perforating. Dorsal aresta absent. Sting with sharp, well sclerotized shaft, probably perforating. Haemocoele development at sting shaft low or reduced. Sting bulb and valve chamber of size similar to sting shaft. Valve chamber with indistinct dorsum in relation to sting shaft base in profile. Internal apophysis present but not too long and probably does not extend significantly into valve chamber. Base of sting arch slightly curved. Basal ridge present but ill-developed, antero-lateral processes and articular processes present. Basal notches open. Campaniform sensilla of valve chamber present beyond basal half of sting shaft. Sting reduction index 31–41. Furcula dorsal arm present with variable length; dorsal arm subtriangular, with single apex; base of dorsal arm narrow in relation to sting bulb in ventral view. Articulation free, linked to sting base by lateral extremities only.

Ergatoid gynes. Head and body only slightly larger than conspecific worker, with more robust gaster; frons drastically different from conspecific worker, rendering the head phragmotic (as in B. conops ). Always wingless; wing buds never fully developed in B. conops , completely absent in B. brasiliensis and in B. delabiei sp. n.

Males (Male unknown for B. fernandezi sp. n.). Total length varying from 2 to 5 mm. Body yellowish to dark castaneous or dark reddish brown. Subopaque integument with gaster brighter than rest of body. Body sculpture denser than in workers. Subrectangular head; falcate subtriangular mandibles with a single apical tooth; anterior border of clypeus convex, resulting in a small anterior denticle when clypeus is seen laterally, and median portion of clypeus inflated in lateral view; frontal carina relatively short and without lobe; frontal lobe obsolete, exposing basal condyle of antenna; antennal scrobes absent; antenna 13 segmented; compound eye ellipsoid, its longitudinal axis perpendicular to median transversal line in lateral view. Notauli well-marked; propodeal spiracle small and distant from declivitous margin; propodeal lobe vestigial. Legs more elongate than in conspecific females. Petiole pedunculate in lateral view.

Larvae (Larva unknown for B. fernandezi sp. n.). Profile attoid. Segmentation indistinct. No leg or wing vestiges observed under SEM. Integument mostly smooth, spinules minute and concentrated in ventrolateral body region, longitudinal smooth strip present along ventral region of body, and dorsum of posterior somites. Hairs sparse, randomly distributed, unbranched, smooth and slightly curved.

Cranium subcircular ( Figs 5 A – D); frons, clypeus, and labrum projecting from cranium; relatively large antenna placed laterad of pronounced area at cranium mid-length with three sensillae, only slightly elevated from head surface; single faceted eye posterior to midlength of cranium. Mandible attoid, broad and short, apical portion abruptly attenuated; with one sharp pointed apical tooth and no subapical teeth. Labrum crescentic, very short and glabrous, with rounded anterior margin. Anterior clypeal margin broadly concave, posterior margin straight. Maxillae with rounded apex, palp shaped as short frustrum, galea relatively elongate and cylindrical paxilliform with three sensilla; labium feebly bilobed, with short rows of minute acute spinules.

Biology. All four known Blepharidatta species are generalist predators that nest in the ground or in the leaf litter; nests are single, short (up to 20 cm) cylinders excavated in the ground or inside rolled leaves or rotting twigs, with one to 10 ergatoid gynes and up to 450 workers in the biggest colonies. Foragers patrol a roughly circular area around the single nest opening, where they collect live or dead arthropods to feed their larvae.

Distribution. B. brasiliensis and B. fernandezi sp. n. are known, respectively, from the central and western Amazon basin, B. conops from different localities in the Brazilian savannas and caatingas, while B. delabiei sp. n. is known from different localities in the Atlantic Forest, eastern Brazil ( Fig. 9).