Solenopsis picea

Solenopsis picea nests under stones in dark clay loam soils. Brood and sexuals were collected in nests in Mexico in May. Solenopsis picea was also collected from a nest in the extremities of dried Psidium pomiferum in Brazil (Forel 1903). This species was collected in the thin partitions separating the chambers of ant gardens inhabited by Crematogaster carinata and Camponotus femoratus in British Guiana (Weber 1943). Habitats include transitional bamboo/cloud forest, hardwood, montane cloud forest, wet montane forest, wet cloud forest, old growth tropical forest, oak ridge and coffee plantations. (Pacheco and Mackay 2013)

Identification
A New World thief ant that is a member of the molesta species complex. (Key to New World Solenopsis Species Complexes)

Pacheco and Mackay (2013) – Worker - This is a black/dark brown (occasionally light brown or somewhat bicolored with the gaster darker than the remainder of the ant), medium sized species (total length 1.56 mm). The head is nearly quadrate, with fine cephalic punctures and short (0.030 mm) hairs. The lateral clypeal teeth are well developed. It has small eyes with 3-5 ommatidia. There are horizontal striae on the mesopleuron and metapleuron. The petiole is noticeable longer than the postpetiole when viewed laterally. Queen - The queen is concolorous brown. The lateral teeth are well developed and extend about 0.030 mm beyond the anterior clypeal border. The scape is thick, 0.090 mm in diameter. Thin vertical striae are present on the frontal lobes. The scape, head and pronotum are covered in coarse punctures. Thin horizontal striae are present on the lower half of the metapleuron and just anterior to the propodeal spiracle. There are teeth present on the bottom of both the petiolar peduncle and postpetiole, however the petiolar peduncle's tooth is better developed than the one present on the postpetiole (which is more like an angle). Male - The male is very dark brown (almost black). The legs and antennae are lighter brown in color. The clypeus is slightly concave with no presence of a tooth, bump or angle on the margin. Tiny striae is present on the clypeus and follow the clypeal margin. Thin vertical striae are present on the head from the ocelli to the frontal lobes. Punctures are present on the first segment of the antennae. No punctures are visible on the head, pronotum or rest of the mesosoma.

Workers are easily confused with those of Solenopsis castor. Solenopis picea are not as dark mahogany brown as is S. castor and the minor segments of the antennae are longer, nearly always greater in length than 0.100 mm (nearly always less than 0.120 mm in S. castor). If queens are available, these two species are easily separated, as the queens of S. picea are large (total length> 4 mm), compared to the much smaller queens of S. castor (TL up to 3 mm). The male of S. picea is similar to a male of Solenopsis pollux, but can be distinguished as S. pollux is slightly larger and has golden yellow antennae as opposed to the brown coloration of S. picea (=S. nigelloides). Additionally, S. picea (= S. nigelloides) lacks coarse punctures on the head and pronotum.

Distribution
Mexico south to Argentina, Brazil, Guiana; Caribbean Region (Cuba, Puerto Rico).

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Belize, Bolivia, Brazil , Colombia, Costa Rica , Cuba, Greater Antilles, Guatemala, Guyana , Honduras, Mexico, Panama, Peru, Puerto Rico.

Biology
Philpot et al. (2018) reported this species was one of the most common ants in an experimental study examining colonization of twigs in shade-coffee forests in Chiapas, Mexico (17.7% of the 202 nests found in 796 recovered twigs).

It has been found nesting in the thin partitions separating nest chambers within the ant gardens inhabited by and  (Weber, 1943) in British Guiana (but is apparently not an ant-garden ant itself).

Nomenclature

 * . Solenopsis picea Emery, 1896g: 89 (w.q.) COSTA RICA.
 * Type-material: syntype workers, syntype queens (numbers not stated).
 * Type-locality: Costa Rica: Jiménez (A. Alfaro).
 * Type-depository: MSNG.
 * Wheeler, G.C. & Wheeler, J. 1955c: 135 (l.).
 * Subspecies of tenuis: Forel, 1912g: 8.
 * Status as species: Forel, 1899c: 80; Wheeler, W.M. 1908a: 131; Forel, 1909a: 250; Wheeler, W.M. 1914b: 43; Mann, 1916: 447; Mann, 1922: 30; Emery, 1922e: 200; Wheeler, W.M. 1925a: 35; Borgmeier, 1927c: 106; Menozzi, 1931b: 267; Aguayo, 1932: 218; Smith, M.R. 1937: 837; Wheeler, W.M. 1942: 204; Ettershank, 1966: 143; Kempf, 1972a: 239; Bolton, 1995b: 390; Branstetter & Sáenz, 2012: 261; Pacheco & Mackay, 2013: 263 (redescription); Bezděčková, et al. 2015: 122; Fernández & Serna, 2019: 816.
 * Senior synonym of nigelloides: Pacheco & Mackay, 2013: 263.
 * Senior synonym of parabiotica: Pacheco & Mackay, 2013: 263.
 * Senior synonym of reducta: Pacheco & Mackay, 2013: 263.
 * Senior synonym of subadpressa: Pacheco & Mackay, 2013: 263.
 * Material of the unavailable name ardua referred here by Pacheco & Mackay, 2013: 263.
 * Distribution: Argentina, Brazil, Colombia, Costa Rica, Guyana, Mexico, Panama, Peru.
 * nigelloides. Solenopsis angulata r. nigelloides Forel, 1913l: 223 (w.q.m.) ARGENTINA (Buenos Aires).
 * Type-material: lectotype worker (by designation of Pacheco & Mackay, 2013: 266), 5 paralectotype workers, 1 paralectotype queen, 1 paralectotype male.
 * Type-locality: lectotype Argentina: Buenos Aires (G. Rovereto); paralectotypes with same data.
 * Type-depositories: MHNG (lectotype); MHNG, MSNG (paralectotypes).
 * Subspecies of angulata: Bruch, 1915: 531; Santschi, 1916e: 378; Emery, 1922e: 199; Creighton, 1930b: 151; Ettershank, 1966: 142; Kempf, 1972a: 233; Bolton, 1995b: 389.
 * Junior synonym of picea: Pacheco & Mackay, 2013: 263.
 * parabiotica. Solenopsis parabiotica Weber, 1943a: 90, fig. 2 (w.q.) GUYANA.
 * Type-material: holotype queen, paratype workers (number not stated).
 * Type-locality: holotype Guyana (“British Guiana”): Mazaruni River, Forest Settlement, 19.viii.1935, no. 295 (N.A. Weber); paratypes with same data but 3.ix.1935, no. 347.2.
 * Type-depositories: AMNH, MCZC.
 * Status as species: Ettershank, 1966: 142; Kempf, 1972a: 238; Brandão, 1991: 379; Bolton, 1995b: 390.
 * Junior synonym of picea: Pacheco & Mackay, 2013: 263.
 * reducta. Solenopsis picea subsp. reducta Menozzi, 1927c: 276 (w.) COSTA RICA.
 * Type-material: syntype workers (number not stated).
 * Type-locality: Costa Rica: San José (H. Schmidt).
 * Type-depository: DEIB (perhaps also in IEUB).
 * Subspecies of picea: Ettershank, 1966: 143; Kempf, 1972a: 239; Bolton, 1995b: 390.
 * Junior synonym of picea: Pacheco & Mackay, 2013: 263.
 * subadpressa. Solenopsis picea r. subadpressa Forel, 1903c: 257 (w.) BRAZIL (Ceará).
 * Type-material: lectotype worker (by designation of Pacheco & Mackay, 2013: 266).
 * Type-locality: Brazil: Ceará (F. Diaz da Rocha).
 * [Note: other syntypes deposited in MHNG.]
 * Type-depository: MCZC.
 * [Also described as new by Forel, 1908e: 66.]
 * Subspecies of picea: Mann, 1916: 447; Emery, 1922e: 200; Wheeler, W.M. 1925a: 35; Borgmeier, 1927c: 106; Ettershank, 1966: 143; Kempf, 1972a: 239; Bolton, 1995b: 391.
 * Junior synonym of picea: Pacheco & Mackay, 2013: 263.

Worker
Pacheco and Mackay (2013) - Measurements (n=14). TL 1.38-2.04 (1.56); HL 0.402-0.540 (0.481); HW 0.336-0.510 (0.411); EL 0.042-0.060 (0.049); ED 0.030-0.042 (0.035); SL 0.282-0.396 (0.336); FSL 0.120-0.180 (0.137); CI 80.0-94.4 (85.4); SI 61.2-79.3 (69.9); PL 0.072-0.108 (0.087); PW 0.090-0.162 (0.125); PI 55.6-82.4 (70.3); PPL 0.102-0.132 (0.109); PPW 0.108-0.180 (0.149); PPI 65.5-94.4 (74.7); WL 0.300-0.450 (0.367); PSL 0.024-0.060 (0.037); PSW 0.024-0.060 (0.036).

Dark brown to light brown, sometimes with gaster lighter in color than body; head square-shaped, cephalic punctures fine; lateral clypeal teeth well developed; extralateral teeth angular to absent; eyes small, black, with 3-5 ommatidia; minor funicular segments 3-8 slender, long (0.137 mm); notopropodeal suture well depressed; horizontal striae on mesopleuron and metapleuron; petiole noticeable longer than postpetiole viewed laterally.

Moderately hairy, with erect and sub erect hairs on all body surfaces; cephalic punctures fine and hairs very short (0.030 mm); hairs on scape short; suberect hairs of petiole and postpetiole curved posteriorly.

Queen
Pacheco and Mackay (2013) - Measurements (n=2). TL 3.96-4.68 (4.32); HL 0.666-0.720 (0.693); HW 0.588-0.660 (0.624); EL 0.186-0.258 (0.222); ED 0.144-0.204 (0.174); MOL 0.048-0.072 (0.060); MOD 0.054-0.060 (0.057); SL 0.456-0.480 (0.468); FSL 0.204-0.282 (0.243); CI 88.3-91.7 (89.9); SI 66.7-68.5 (67.6); PSL 0.048-0.066 (0.057); PSW 0.060-0.072 (0.066); PL 0.144-0.150 (0.147); PW 0.240-0.324 (0.282); PI 44.4-62.5 (53.5); PPL 0.240; PPW 0.264-0.438 (0.351); PPI 54.8-90.9 (72.9); WL 0.900-0.960 (0.930).

Concolorous brown; head quadrate; lateral clypeal teeth well developed, extend 0.030 mm beyond anterior clypeal border; clypeal carinae well developed, extend posterior to antennal insertions; extralateral teeth smaller in size, angular; scape thick, 0.090 mm in diameter; thin vertical striae on frontal lobes; scape, head, pronotum with coarse punctures; eyes small; thin horizontal striae on entire side of propodeum; petiole and postpetiole horizontally striate, subpeduncular tooth well developed, tooth ventrally on postpetiole angular.

Abundantly hairy, hairs present on all body surfaces; nearly every puncture on body has suberect hair.

Male
Pacheco and Mackay (2013) - Measurements (n=1). TL 3.48; HL 0.600; HW 0.642; EL 0.270; ED 0.180; MOL 0.054; MOD 0.078; SL 0.222; FSL 1.68; CI 107.0; SI 37.0; PSL 0.060; PSW 0.066; PL 0.150; PW 0.264; PI 56.8; PPL 0.180; PPW 0.330; PPI 54.5; WL 0.840.

Dark brown, legs and antennae lighter brown; clypeus slightly concave, with no presence of tooth, bump or angle on anterior margin; vertical striae follow clypeal margin; thin vertical striae extend from ocelli to frontal lobes; three ocelli clear, eyes black; scape with coarse punctures; no punctures visible on head, pronotum or remainder of mesosoma; side of propodeum entirely striated; sparse striae present basally on petiole and postpetiole; no visible tooth, angle or bump on subpeduncular process or subpostpetiolar process.

Abundantly hairy, with hair present on all body surfaces, most hairs are suberect and curve posteriorly.

Type Material
Solenopsis angulata nigelloides, Museo Civ. Genova, Forel Coll., Argentina, Buenos Aires x. 1912, G. Roverto (lectotype worker, 5 paralectotype workers, 1 paralectotype queen and 1 paralectotype male [here designated], ). Solenopsis picea subadpressa Brazil, Ceara, Dr. Rocha (lectotype worker M.C.Z. cotype 1, 22616, ). Solenopsis angulata carettei ardua Sammlung, Dr. F. Santschi, Kairouan Argentina, Parana, Rio Negro, Reichensperger, 1928 (2 workers, 1 queen NHMB). Solenopsis parabiotica, types not found, specimens apparently identified by Weber found in MCZC (10 workers).

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