Cephalotes placidus

This species has been collected from a recent treefall, in scrub forest and in a rainforest clearing. Besides these nesting and habitat notes, nothing is known about the biology of .

Identification
A member of the atratus clade distinguishable from the other species, in the worker, for the following combination of characters: long, thick propodeal spines, deep foveolate sculpture and broad gastral lamella. The gyne and the male of placidus are similar to Cephalotes opacus but have much stronger body sculpture and longer propodeal spines. (de Andrade and Baroni Urbani 1999)

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

Nomenclature

 * . Cryptocerus placidus Smith, F. 1860c: 76 (m.) BRAZIL (Amazonas).
 * Type-material: holotype male.
 * [Note: lectotype status for the specimen, suggested by De Andrade & Baroni Urbani, 1999: 156, is redundant as original specimen was unique; referred to as holotype by Kempf, 1959a: 92.]
 * Type-locality: Brazil: São Paulo (no collector’s name).
 * Type-depository: OXUM.
 * Snelling, R.R. 1966: 38 (w.q.).
 * Combination in Cephalotes: Emery, 1924d: 304;
 * combination in Eucryptocerus: Kempf, 1959a: 92;
 * combination in Cephalotes: De Andrade & Baroni Urbani, 1999: 156.
 * Status as species: Smith, F. 1862d: 411; Mayr, 1863: 406; Roger, 1863b: 38; Dalla Torre, 1893: 144; Forel, 1895b: 134; Emery, 1924d: 304; Borgmeier, 1927c: 115; Kempf, 1951: 127; Kempf, 1959a: 92 (redescription); Kempf, 1960e: 396; Kempf, 1963c: 437; Kempf, 1972a: 107; Brandão, 1991: 343; Bolton, 1995b: 189; De Andrade & Baroni Urbani, 1999: 156 (redescription); Bezděčková, et al. 2015: 116; Sandoval-Gómez & Sánchez-Restrepo, 2019: 913.
 * Senior synonym of fenestralis: Kempf, 1963c: 437; Kempf, 1972a: 107; Bolton, 1995b: 189; De Andrade & Baroni Urbani, 1999: 156.
 * Distribution: Bolivia, Brazil, Colombia, French Guiana, Guyana, Peru.
 * fenestralis. Cryptocerus fenestralis Smith, F. 1876d: 607 (q.) BRAZIL (Amazonas).
 * Type-material: holotype queen.
 * Type-locality: Brazil: São Paulo (H.W. Bates).
 * Type-depository: BMNH.
 * Combination in Paracryptocerus: Kempf, 1951: 232.
 * Status as species: Dalla Torre, 1893: 142; Forel, 1895b: 133; Emery, 1924d: 309; Borgmeier, 1927c: 118; Kempf, 1951: 232.
 * Junior synonym of placidus: Kempf, 1963c: 437; Kempf, 1972a: 107; Bolton, 1995b: 189; De Andrade & Baroni Urbani, 1999: 156.

Worker
de Andrade and Baroni Urbani (1999) - Head subquadrate, less than one fourth broader than long. Border of the frontal carinae with a small denticle in the middle. Vertexal angles with two pairs of teeth; only the internal tooth with lamellaceous border and ca. twice larger than the external one.

Mesosoma. Anterior pronotal border with a superficial or without a notch in the middle. Pronotal dorsum with a pair of developed denticles. Propodeum with a pair of spines ca. 1.5 longer than the basal face.

Petiole subcylindrical, with truncate anterior face, unarmed and gently converging posteriorly. Postpetiole slightly higher than the petiole; anterior half of the postpetiolar sides broadly convex, in some specimens with truncate apex; posterior half converging posteriorly.

Gaster with a pair of broad lamellae narrowing at the apex.

Legs. Mid and hind femora without angle or denticle medially but with a pair of faint longitudinal carinae on the two posterior thirds. Mid and hind basitarsi long, slightly compressed laterally at the base; their diameter constant through the whole length.

Sculpture. Foveae on the mesosoma and pedicel much deeper than in opacus and oculatus.

Pilosity and colour. As in the other species of the clade.

Measurements (in mm) and indices: TL 8.04-8.80; HL 1.84-2.04; HW 2.24-2.48; EL 0.47-0.49; PW 2.44-2.56; PeW 0.60-0.70; PpW 0.70-0.83; HBaL 1.00-1.16; HBaW 0.23-0.27; CI 119.1-1224 .0; PI 96.9-100.0; PPeI 365.7-380.0; PPpI 308.4-325.7; HBaI 23.0-23.3.

Queen
Snelling (1966) - Total length, 11.4 mm.; forewing, 10.9 mm; maximum head width, 3.0 mm; maximum head length (from anterior margin of lateral lobes), 2.9 mm; maximum thoracic width, 3.0 mm. Integument dull black, except the dark reddish-brown apical tarsal segments.

Head, excluding mandibles, very slightly longer than wide; mandibles strongly rugose; clypeus about as broad as long, triangular; frontal carinae slightly convergent anteriorly, margin of lower one-third slightly crenulate, with a few clavate setae occiput with a pair of low, pointed tubercles immediately above posterior ocelli; a low pointed tubercle on each side above eyes, with a similar tubercle immediately behind; front distinctly convex when viewed from above; occipital emargination rather deep; cheeks very broad, almost one-third as broad as head is long.

Pronotum nearly vertical anteriorly; humeral angles projecting forward as a narrow spine when viewed from above, pronotal crest strong laterally, absent medially, carinate, the carina raised on each side of median line as a pair of low humps, entire carina slightly crenulate; mesopleura with small spine above mid coxae; epinotum narrow, with a pair of spines directed caudad, the spines about as long as distance between their bases.

Petiole short, about twice as broad as long, anterior face vertical; postpetiole not swollen dorsally, only slightly swollen laterally; petiole and postpetiole without ventral projections; gaster more elongate than in worker, about one-third longer than broad, first tergite emarginated basally, disc with very fine striae which converge medially, anterior carina of first tergite distinct as far back as spiracle; remaining tergites discally roughened, all tergites with a narrow, dull, impunctate m arginal band; first ventrite dull, sparsely punctate with a few irregular striae laterally; remaining ventrites roughened disc ally; all ventrites with narrow, impunctate apical margins which are slightly more shiny than those of tergites.

Integument generally dull, subopaque, mesoscutum, scutellum and abdomen somewhat shinier. Punctures of front moderate in size, separated by about a puncture diameter, becoming a little finer and sparser below, somewhat less distinct on pronotal lobes j punctures of occiput coarser than those of front, separated by a puncture diameter or less; cheeks rugoso-punctate; punctures of anterior and upper faces of pronotum equal to those of occiput, sparser medially, of lateral face coarse, rather close; punctures of mesoscutum slightly elongated, separated by a puncture diameter or less, becoming sparser and fainter laterad; those of disc about equal to those of occiput; punctures of upper mesopleural plate slightly finer than those of adjacent portion of pronotum, separated by slightly less than a puncture diameter; punctures of lower half of mesopleura, entire metapleura, lateral and posterior faces of epinotum obscure, scattered, the integument opaque, minutely granulose; punctures of scutellum slightly elongate, equal to those of  mesoscutum, separated by a puncture diameter or less the integument slightly more shiny than elsewhere; punctures of basal face of epinotum coarse, deep, subcontiguous. Wings fuscous infuscate, except for clear submarginal cell; marginal cell closed and appendiculate apically, about 3.5 times as long as wide; submarginal cell about three-fourths as long as marginal; otherwise as figured by Kempf (1959:93) for the male.

de Andrade and Baroni Urbani (1999) - de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 12.86-13.70; HL 2.48-2.56; HW 3.00-3.12; EL0.64; PW 3.04-3.20; PeW 0.92-1.00; PpW 1.08-1.10; HBaL 1.32; HBaW 0.32-0.34; CI120.0-121.9; PI 97.5-98.7; PPeI 320.0-330.4; PPpI 281.5-291.0; HBaI 25.7.

Male
Kempf (1959), translated in de Andrade and Baroni Urbani (1999) - Total length 9.7 mm; length of the cephalic capsule 1 .45 mm; head width, including the eyes, 2.21 mm; length of the thorax 3.12 mm; length of the fore wing 7.6 mm. Black; funicular segments II - XII, legs, except the coxae, and gaster ferruginous. integument opaque, finely and densely punctuate; first gastral tergite, particularly in the center, and legs, particularly on the extensor face of the femora, with sculpture more superficial and slightly shining. Head with larger foveolae, superficial and sparse; with very short rugae disposed radially around the eyes; occiput rugose-reticulate. Pronotum, shield and scutellum with foveolae slightly larger but equally superficial and sparse. Basal face of the epinotum irregularly reticulate-rugose; declivous face with regular rugae, vertical and thinner. Dorsum and sides of the peduncular segments with fine, spaced, longitudinal rugae. Erect pilosity thick, yellowish, abundant on the body, nearly entirely lacking on the first gastral tergite and on the legs, excepted the flexor face of the femora and of the tibiae. Gaster with thin and short, sparse hairs, adherent to the integument. Pubescence more dense on the legs, very dense and very short on the funiculi.

Head transverse; interocular distance slightly larger than the length of the cephalic capsule. Clypeus considerably convex, with anterior face sloping and truncated in the middle, clearly separate from the superior face, the two forming a right angle, when seen in profile. Occipital angles with a triangular tooth large and projecting. Thoracic shoulders obtuse, not marked. Basal face of the epinotum with lateral borders converging behind, the triangular lobes of the posterior angle with pointed and sharp borders; postero-median impression without distinct margination in the middle. First tarsomere of the middle and hind legs slightly compressed, not remarkably enlarged. The two peduncular segments bear on each side a projecting tubercle, those of the petiole more ventral, not visible when seen from top. First gastral tergite 1 1/3 times longer than wide, the base superficially impressed in the middle of the articulation of the postpetiole.

Wings slightly darkened, with the venation dark-brown. Fore wing with black pterostigma, cubital cell nearly light and hyaline. Hind wing with venation originating from the anterior side of the radius, in the middle of the first abscissa, and with 9-10 hamuli.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 7.72-9.40; HL 1.12-1.36; HW 1.48-1.76; EL 0.52-0.65; PW 1.28-1.60; PeW 0.56-0.72; PpW 0.64-0.80; HBaL 1.16-1.28; HBaW 0.16- -0.20; CI 120.6-132.1; PI 102.8-119.3; PPeI 220.0-235.3; PPpI 193.7-222.2; HBaI 13.8-15.6.

Type Material


de Andrade and Baroni Urbani (1999):

Male. Type locality: Sao Paulo de Olivenca (Amazonas, Brazil). Type material: holotype male labelled: 1 st label "St. Paulo Braz.", 2nd label "Cryptocerus placidus Smith", 3rd label "Coll. Smith 1829", 4th label (pink) "Eucryptocerus placidus (Sm.) Holotypus [added by Kempf]”, 5th label "Eucryptocerus placidus (Fr. Smith, 1 860) det. W. W. Kempf", 6th label "Type Hym.: 1041 Cryptocerus placidus Smith Hope Dept. Oxford", in, examined. A second specimen in , labeled "C. placidus, type. Sm., Journ. Ent. I.76, 59 2", examined, is likely to belong to another species which we are unable to identify. We consider Kempf’s (1959) re-description of the Oxford specimen as a lectotype designation.

Cryptocerus fenestralis Gyne. Type locality: Sao Paulo de Olivenca (Amazonas, Brazil). Type material: holotype gyne labelled "Cryptocerus fenestralis., (type) Smith, St. Paul, 70 16" in (Kempf, 1963: 437), examined.

Cryptocerus placidus

Holotype male in. Labelled “S. Paulo Brazil.”

References based on Global Ant Biodiversity Informatics

 * Bezdeckova K., P. Bedecka, and I. Machar. 2015. A checklist of the ants (Hymenoptera: Formicidae) of Peru. Zootaxa 4020 (1): 101–133.
 * Escalante Gutiérrez J. A. 1993. Especies de hormigas conocidas del Perú (Hymenoptera: Formicidae). Revista Peruana de Entomología 34:1-13.
 * Fernández F., E. E. Palacio, W. P. Mackay, and E. S. MacKay. 1996. Introducción al estudio de las hormigas (Hymenoptera: Formicidae) de Colombia. Pp. 349-412 in: Andrade M. G., G. Amat García, and F. Fernández. (eds.) 1996. Insectos de Colombia. Estudios escogidos. Bogotá: Academia Colombiana de Ciencias Exactas, Físicas y Naturales, 541 pp
 * Fernández F., and E. E. Palacio. 1995. Hormigas de Colombia IV: nuevos registros de géneros y especies. Caldasia 17: 587-596.
 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
 * Franco W., N. Ladino, J. H. C. Delabie, A. Dejean, J. Orivel, M. Fichaux, S. Groc, M. Leponce, and R. M. Feitosa. 2019. First checklist of the ants (Hymenoptera: Formicidae) of French Guiana. Zootaxa 4674(5): 509-543.
 * Kempf W. W. 1951. A taxonomic study on the ant tribe Cephalotini (Hymenoptera: Formicidae). Revista de Entomologia (Rio de Janeiro) 22:1-244
 * Kempf W. W. 1959. Sôbre algumas formigas Cephalotini do Museu de Oxford (Hymenoptera, Formicidae). Revista Brasileira de Biologia 19: 91-98.
 * Kempf W. W. 1960. Insecta Amapaensia. - Hymenoptera: Formicidae (segunda contribuição). Studia Entomologica (n.s.)3: 385-400.
 * Kempf W. W. 1963. Nota sinonímica acêrca de formigas da tribo Cephalotini (Hymenoptera, Formicidae). Revista Brasileira de Biologia 23: 435-438.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Wilson, E.O. 1987. The Arboreal Ant Fauna of Peruvian Amazon Forests: A First Assessment. Biotropica 19(3):245-251.
 * de Andrade, M.L. & C. Baroni Urbani. 1999. Diversity and Adaptation in the ant genus Cephalotes, past and present. Stuttgarter Beitrage zur Naturkunde Serie B 271. 893 pages, Stuttgart