Blepharidatta conops Kempf

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) : 46-49

Blepharidatta conops Kempf

( Figs 1 C – D, 2 C – F, 3 C – D, 4 C – D, 5 A – E, 7 A – I, 9)

Blepharidatta conops Kempf, 1967: 355 , workers. Figs. 4, 5. Brazil.

References: Brandão et al. 1998, 2001; Diniz et al., 1998; Silva et al. 2002.

Holotype worker: BRAZIL: Mato Grosso do Sul: Três Lagoas, Faz. Retiro das Telhas , 28.v.1964, Exp. Depto Zoologia ( Kempf coll. # 4131 ) ( MZSP, examined) .

Holotype measurements: HL 1.05; HW 0.88; SL 0.75; ML 0.3; WL 1.2; PL 0.7; Ppl 0.25; Hfl 1; GL 1.05.

Paratypes: 3 workers, same data as Holotype ( MZSP, examined).

Diagnosis (worker). Comparatively large (total length 45– 47 mm). Body chestnut to blackish, with always lighter, sometimes reddish, gaster. Body mostly shiny, feebly areolate and irregularly rugulose. Eye evidently protruding and conical. Propodeal spine shorter than petiole in lateral view. Petiolar node weakly elevated, long and cylindrical.

Worker measurements (n=9): HL 0.9–1.05; HW 0.75–0.9; SL 0.65–0.9; ML 0.25–0.3; WL 0.95–1.2; PL 0.55–0.7; Ppl 0.2–0.3; Hfl 0.75–1.0; GL 0.8–1.05.

Worker description ( Figs 1 C – D). Color chestnut to blackish, with contrasting lighter gaster and translucid frontal carina; appendages brownish. Body sculpture varying from areolate-rugose to almost indistinctly foveolate, superposed by irregular rugulae on head, mesosoma, petiole and postpetiole; gaster mostly smooth to weakly areolate near the postpetiolar insertion. Mandible longitudinally striate; central portion of clypeus finely covered by irregular and short transverse striae. Sculpture of scrobe strongly variable, from uniformly areolate to divided into four distinct parts, the anterior one smooth and deeper than the rest; second area with 3–4 transverse curved striae over the areolate rugae, followed by a deep, almost smooth area, and a posterior area of transverse sculpture units, ending with areolate rugulae. Dorsal surface of head ranging from longitudinally areolate-rugose to predominantly smooth and micro-striate at central disc and occipital lobes. Compound eye set within a longitudinal row of polygonal cells formed by rugulae, better seen in lateral view. Mesosoma variably sculptured throughout its entire surface, generally with irregular, vermiculate, longitudinal rugae over the areolate sculpture. Petiole and postpetiole densely areolate and longitudinally rugose in lateral view. Areolate sculpture, when present, concentrated on anterior fifth of gaster, otherwise smooth and shining. Appendages regularly areolate.

In general, body covered by sparse hairs; hairs stiff, long, slightly curved, and uniform in width; some in pairs. Dorsum of mandible with subdecumbent to appressed flexuous short hairs; frontal carina with 12–15 regularly spaced and upwards bent hairs. Dorsum of petiolar node and postpetiole covered by sparse hairs, mostly in pairs, including ventral faces. Anterior face of procoxa with few long and erect hairs. Legs otherwise covered by decumbent short hairs.

Head occipital corner expanded in frontal view. Scape and funiculus almost entirely lodged in the scrobe; frontal carina totally covering the scrobe in frontal view, hiding the antenna and the internal area of scrobe with head in frontal view; compound eye evidently protruding and conical, with about nine 12 facets along its maximum diameter. Ventral surface of head slightly convex, making the anterior region of head wider than rest in lateral view.

Promesonotum slightly convex medially in frontal view, followed by an attenuated curve to lateral margin; dorsal outline of mesosoma convex in profile, with anterior margin angular to evenly rounded; dorsum of promesonotum elevated above level of propodeum; pronotal humeral corner projecting in dorsal view; anteroventral corner pointed; metanotal groove shallow to indistinct in lateral view; dorsal profile of propodeum straight; propodeal spine relatively long and curved upwards, with broad base; infraspinal lamella well-developed and fused to propodeal lobe; propodeal lobe subquadrate in side view, length close to one-third of propodeal spine length.

Pedunculate petiole with a weakly elevated, long and cylindrical node; postpetiole weakly convex dorsally and without ventral processes. Gaster suboval with tergum I anterolaterally feebly angular in dorsal view.

Sting apparatus ( Figs 7 A – I). Spiracular plate subquadrate, spiracular external margin separated from posterior plate margin by a distance one and a half times the spiracle internal diameter; ventral tubercle absent. Quadrate plate apodeme area smaller than plate body. Anal plate as in other Blepharidatta species. Oblong plate with long posterior apodeme; subterminal tubercle present. Gonostylus with short membranaceous terminal. Triangular plate dorsal tubercle prominent; median tubercle absent. Lancets as in other Blepharidatta species. Anterolateral processes of sting base with weak anterior tubercle. Sting reduction index 31–41. Furcula dorsal arm length almost equal to side arms´length; lateral arms narrower at base than dorsal arm.

Gyne measurements (n=2): HL 1.05–1.15; HW 1.35–1.45; SL 0.55–0.65; ML 0.3–0.35; WL 1.25; PL 0.65; Ppl 0.26–0.3; Hfl 0.95; GL 1.35–1.45.

Gyne (ergatoid) description ( Figs. 2 C – F). Larger and drastically distinct from conspecific worker. Surface sculpturing extremely variable, especially on head and anterior slope of pronotum, which can be predominantly smooth and minutely foveolate or densely areolate-rugose. Pilosity denser than in the workers, mainly on mesosomal and metasomal dorsum.

Head and anterior face of pronotum phragmotic; dorsal surface of head rounded, with the frontal carina enormously expanded so that the lateral margins of head, eyes, clypeus and mandibles are totally concealed in frontal view; outline of cephalic disc only interrupted anteriorly by a median emargination, which marks the limits between the frontal lobes. Mesosoma subrectangular and robust. Anterior face of pronotum vertical and rounded dorsally in frontal view, forming with the head a large disc; sides of metanotum sometimes with variably developed wing bud; propodeal spines shorter than those of workers. Gaster well-developed.

Male measurements (n=2): HL 0.8–0.95; HW 0.55; SL 0.3; ML 0.1–0.15; WL 1.3–1.45; PL 0.6; Ppl 0.25– 0.35; Hfl 1.0–1.11; GL 1.10–1.25.

Male description (Figs 3 C – D). Body uniformly chestnut to dark-brown, with slightly darker gaster; appendages yellowish. Body entirely areolate with vermiculate longitudinal rugulae over the lateral portions of mesosoma and waist. Gaster smooth and shining. Long, subdecumbent, whitish hairs densely covering the entire body; appendages densely covered by subdecumbent hairs.

Head rounded in frontal view. Mandible short and subfalcate, with vestigial denticles on the masticatory margin; scape very short, not reaching the posterior margin of eye in frontal view; pedicel enlarged and relatively short; first funicular segment about twice as long as the pedicel. Eye huge and extremely protruding, occupying about three-fourths of head in lateral view. Ocelli present and equally developed.

Pronotum vestigial in dorsal view, with almost inconspicuous humeral angles; scutum large, almost straight anteriorly and with a slightly convex posterior margin; notauli weakly impressed. Prescutellum narrow; scutellum wider than long. Metanotal suture well-marked and shallow. Propodeum unarmed, dorsal and posterior margins continuous and gradually inclined posteriorly.

Wings dark amber in color and covered by a dense pubescence; venation reduced; pterostigma elliptical and well-marked; longitudinal veins Sc+R, Rs, M, Cu, and A present; Rs, M, Cu not extending to the external margins of the wing; cells C, R and SR closed. Hind wing with R+Rs and M+Cu veins only; four sub-median hamuli present.

Petiole pedunculate, with weakly elevated, long and cylindrical node; ventral processes absent. Postpetiole subrectangular in dorsal view, longer than broad, and attached to gaster by almost its full width. Gaster elongate, tergite I anterolaterally feebly angular.

Larva (late instar) description ( Fig 5 A – E). Body hairs of two main sizes: short (ca. 50–60 microns) sparsely dispersed throughout body, but commoner in the spinulose areas, and long (more than 200 microns) flexuous tapered hairs in a row around pronotum and some around anus, most broken off at base ( Fig. 5 E). Eight stouter hairs present on frons (six anteriorly in a row on a fold at mid-length projection and two dorsoposteriorly); clypeal anterior margin with a row of seven minute hairs (circa 3 microns), the central ones even smaller.

Throphorhinium ventral plate with 6 to 7 transverse spinulose striae. Labium with dorsal face forming two blunt low spinulose projections, spinules covering all surfaces but palps. Paxilliform palp with three sensillae. Opening of sericteries not visible in frontal view.

Comments. Blepharidatta conops has been recorded in different central Brazilian states, mostly those covered by cerrado or caatinga vegetation: western Bahia, southwestern Ceará, Goiás, Maranhão, Minas Gerais, Mato Grosso, Mato Grosso do Sul, Piauí and Tocantins. It is the best studied species in the genus thus far and has been subject of several published studies by the Museu de Zoologia da USP team. In a series of papers, Brandão, 2000, Brandão et al. 1998, 1999, 2000, 2001, 2008; Diniz et al., 1998; Silva, 2003, Silva & Brandão, 2001, and Silva et al., 2001, 2002, published detailed biological observations on B. conops , briefly summarized below.

Jorge L. M. Diniz studied 71 nests of B. conops at Chapada dos Guimarães, Mato Grosso, Três Lagoas and Selvíria in Mato Grosso do Sul (Diniz et al., 1998). Pereira et al. (2014) studied a population of B. conops with 29 nests in Crateús, Ceará state. All but one of these nests were excavated in the soil; one odd nest also occupied part of a hollow dry branch fallen on the soil. Nest populations varied from a few individuals to a maximum of 248 workers in the savannas and 437 in Ceará, and only one nest contained two ergatoid gynes; all other are monogynous, although in some nests no gynes were recorded, possibly missed during excavation. Blepharidatta conops nests are easily spotted by the carcass ring the workers carefully arrange around the nest opening. Once one gets used to this search image, it becomes extremely easy to spot the nests. The carcasses around the nest opening are similar in nature to those found in the bottom chamber of the nest; field and laboratory observations suggest the workers collect live arthropods or carcasses, bring them inside the nest for larval feeding, and then put them in the carcass ring around the single nest opening. Populations are rather dense, although separated sometimes by several kilometers, reflecting the low dispersal ability of ergatoid gynes.

Pereira et al. (2014) argue that B. conops populations from Ceará could represent a distinct although closely related species, mostly because of the almost flat anterior cephalic disks of Ceará ergatoids ( Fig. 2 E) and because this population was collected in a locality within the semi-arid Caatinga, while other B. conops populations come from central Brazil savannas. Brandão et al. (2001) already noticed the extreme variation in the sculpture of the ergatoid gynes frontal disc, but were not able to find a single case in which two forms occur sympatrically. They related this variation to the ergatogyny of the gynes that enhances the genetic viscosity of populations, resulting in local variants. In the case of the Ceará population, the ergatoids show the same sculpturing pattern as in other localities, composed by polygonal units separating punctuated areas, although the sculpture units are not so densely packed in some regions of the disc as in other places, rendering the head and pronotal front more regular (see discussion and figures in Brandão et al. 2001). Moreover, we studied worker larvae of cerrado and caatinga populations, confirming the morphological identity of the immatures ( Fig. 5). Pereira et al. (2014) also described the striking similarities among B. conops populations and that of Crateús, Ceará, in nest architecture, in prey diversity found inside nests and the carcass rings, preferred daily time for foraging activities (with two peaks of activity), and other traits. Additionally, the measurements of the Ceará workers and gynes fall well within the range of other B. conops population measurements. We see no evidence of the existence of a different Blepharidatta species in Ceará.

Material examined: BRAZIL: Bahia: Barreiras , 15.v.2001 (“Cerrado-solo”), 12o08’59,7”S 45º09’31,5”W, T22 P, E.B.A. Koch, 1 worker; same locality and date, T22P, K.S. Carvalho, 4 workers [ MZSP] ; Ceará: Crateús, RPPN Serra das Almas , 0 5o00’S 41o00’W, 21.iv. 2003, Y. Quinet (pitfall) 70 workers; same locality (Grajaú), 03– 08.vi.2009, Brandão et al. col., 2 workers, 1 gyne, 1male; same locality (Açude), 2 males, 1 gyne [4 workers CPDC, 4 workers DZUP, 24 workers EUEC, 6 workers HCJG, 4 workers INPA, 4 workers MCZC, 4 workers, USNM, 20 workers, gyne, male MZSP ; Goiás: Cascalheira, vi.2009 (“parcela 9, armadilha E ”), Valentim et al. col., 2 workers [ MZSP] ; Campinaçu, Serra da Mesa, 13o52’S, 48º23’W, 18.ii – 02.iii.1998, Silvestre et al. col., 33 workers [6 DZUP, 6 HCJG, 21 MZSP] ; Colinas do Sul, Serra da Mesa , 02– 15.vii.1995. 14º01’S 48º12’W, Silvestre et al. col., 46 workers, 4 males, 2 gynes [6 CPDC, 6 DZUP, 6 HCJG, 18 workers, 4 males, 2 gynes MZSP] ; Mineiros, Parque Nacional das Emas , 18º19’S 52º45’W, 15.i.2004, R. A. Carvalho, #11 ( em Cerrado, Campo limpo, sob ninho de Cornitermes cumulans , 6 workers ; same data #8, 18.i.2004, 9 workers ; same data, # 67 , 23.i.2004, 9 workers [ MZSP] ; Niquelândia, 24.ix – 6.x.1995, Silvestre et al. col. 48 workers, 2 males; same locality, 16.xi.2013, T. Carrijo col. 1 gyne, 4 workers [ MZSP] ; Serranópolis, Pousada das Araras , 18º18’S 51o08’W, 14.v – 18.vi.2000, P.R. Silva & C. Prado cols., 13 gynes, 1 male, 1 worker (reared in the lab) [ MZSP] ; Maranhão: Balsas, Gerais de Balsas , (“isca solo, lote 31 reserva”) 4– 5.xi.1999, 8o34’S 46o42’W, Brandão et al. col., 8 workers, 4 gynes [ MZSP] ; Estreito, Fazenda Itaueiras , 0 6o31’54,4”S 47o22’16,0” W, 7– 13.i.2005, Silva, R.R. & R.M. Feitosa (Winkler), 21 workers [ MZSP] ; Mato Grosso: U.H. Manso (“isca chão, manhã”), 13.viii.1988, H.C. Morais col., 14 workers [ MZSP] ; Chapada dos Guimarães, Faz. Buriti , 14.i.1985, J.L.M. Diniz col., 9 workers [3 DZUP, 3 HCJG, 3 MZSP] ; Chapada dos Guimarães, Faz. Chafariz (“isca sardinha sítio III”) 30.ix.2005, F.H.O. Silva, 2 workers [ MZSP] ; Fátima , 8.iii.1971, W.W. Kempf col. and det., 1 worker [ MZSP] ; São Lourenço , vi.1974, M. Naves (Kempf coll. 11579 ), 3 workers [ MZSP] . Mato Grosso do Sul: Três Lagoas, Faz. Retiro das Telhas, 28.v.1964, Exp. Depto Zoologia ( Kempf coll. # 4131 ), 4 workers (holotype and paratypes) [ MZSP] ; Selvíria, CECA Reserva , 7.i – 18.xi.1985, J.L.M. Diniz (# 2221 , 2232 , 2242), 1 male, 1 gyne, 3 workers ; same locality and collector (# 2279 ) 6 workers [3 workers HCJG, gyne and 6 workers MZSP] ; Minas Gerais: Grande Sertão Veredas , 12.x.2012 (“coleta manual”), T. Camp col., 1 worker ; Paracatu (“cerrado” ), 2.iii.1989, Márcio Naves col., 1 worker [ MZSP] . Piauí: Bom Jesus , 0 9.19163 S 44.84255W, 10.xi.2010 (solo), W.T. Frizzo & H. Vasconcelos, 1 worker [ MZSP] . Tocantins: Babaçulândia , 07º02’19.0”S 47º52’03,4”W, 14– 19.i.2005, R. Silva & R. Silvestre (from several leaf litter samples) 19 workers [3 DZUP, 3 HCJG, 13 MZSP] ; Palmeiras do Tocantins , 06º49’12.1”S 47º3’48.6”W, 14– 19.i.2005, R. Silva & R. Silvestre, 1 worker [ MZSP] ; Paranã, Faz. Caldas 12º48’51.6”S 47º53’55.3”W, 12.x.2004, R.R. Silva & B.H. Dietz (“isca solo cerrado sensu stricto ”), 2 workers [ MZSP] ; Paranã 12º56’03.3”S 47º57’42.5”W, R.R. Silva & B.H. Dietz (mata ciliar), 1 worker [ MZSP] ; Paranã, Rio Ouro Fino, Faz. Contenda , 12º56’03”S 47º57’42”W, R.R. Silva & B.H. Dietz, 1 worker [ MZSP] ; Aguiarnópolis , 06º36’49.4”S 47º 8’52.2”W, 14– 19.i.2005, R. Silva & R. Feitosa (from several leaf litter samples), 8 workers [ MZSP] .