Solenopsis succinea

Practically nothing is known of the habits of this interesting species. It nests in rotting logs in upland forests and the workers have been taken on decaying fruit. As Dr. Santschi has observed the small size and aberrant mandibles of the female point strongly to habits of a temporary social parasite (Creighton 1930). Solenopsis succinea was collected in a tropical rainforest in Guatemala. Foragers were found on rocky loam soil and nesting in a tree stump at 68 m in elevation. (Pacheco and Mackay 2013)

Identification
A New World thief ant that is a member of the wasmannii species complex.

Pacheco and Mackay (2013) – Worker - The workers are relatively large (2.2 mm total length), nearly as long as the queen (3.5 mm total length) and male (2.9 mm total length). The head is quadrate and the eyes have at least two ommatidia. Erect and suberect hairs are sparsely scattered on all body surfaces. The minor funicular segments are long at ~0.2 mm. The anterior border of the clypeus is straight, lacking the lateral and extralateral teeth. Queen - The queen is relatively large. It is golden yellow with the gaster a slightly lighter yellow. The head is nearly quadrate with small cephalic punctures. It has a 10 segmented antenna. The mandibles have two teeth present at the uppermost portion. No carinae are present on the clypeus, the lateral teeth are only present as bumps and the extralateral teeth are absent. Male - The male very similar to the queen. It is large, golden yellow with the gaster a lighter yellow. The head is nearly quadrate with small punctures present. The antenna has 11 segments.

The lack of clypeal carinae and its large size, together with the 10-segmented antenna of the queen and 11 segmented of the male make this species relatively easy to identify and it would be unlikely to be confused with others, except for Solenopsis bicolor. However, Solenopsis succinea is recognized by its unusual clypeal form.

Solenopsis inermiceps was considered to be a synonym by Creighton (1930). Unfortunately, we have only been able to find a single, headless worker cotype. It is appears to be closely related to S. succinea, but differs in being much smaller (referred to by Wheeler and Mann, 1914). The other three workers in the type series were not found, but Wheeler and Mann (1914) mention that they are larger. Based on the description and lack of material, the synonymy is left in place. A single worker from Saint Vincent (CWEM) suggests S. inermis is not conspecific, but a final decision must await the discovery of other type specimens or until more specimens are collected from Haiti.


 * Key to New World Solenopsis Species Complexes

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Brazil, Costa Rica , Greater Antilles, Guatemala, Haiti, Lesser Antilles, Mexico, Puerto Rico, Saint Vincent and the Grenadines.

Nomenclature

 *  succinea. Solenopsis succinea Emery, 1890b: 52 (w.q.m.) COSTA RICA. [Also described as new by Emery, 1894k: 56.] Combination in S. (Diagyne): Santschi, 1923c: 267. Senior synonym of inermiceps: Creighton, 1930b: 139; of nicai: Pacheco & Mackay, 2013: 313.
 * inermiceps. Solenopsis inermiceps Wheeler, W.M. & Mann, 1914: 20, fig. 7 (w.) HAITI. Junior synonym of succinea: Creighton, 1930b: 139.
 * nicai. Solenopsis succinea r. nicai Forel, 1913l: 222 (w.) BRAZIL. Santschi, 1923c: 267 (q.m.). Combination in S. (Diagyne): Santschi, 1923c: 267. Junior synonym of succinea: Pacheco & Mackay, 2013: 313.

Worker
Creighton (1930) - Length 1.9-2.5 mm.

Head, exclusive of the mandibles, slightly less than one-sixth longer than broad, the sides convex, the head broadest a little behind the middle, the occiput with a broad and shallow, concave impression. Clypeus very little projecting, its anterior edge sinuate, the median lobe broad and slightly concave, without carinae or teeth. Mandibles smooth, narrow and armed with four teeth, the innermost tooth much smaller than the rest. Eyes of three or four poorly defined facets, situated approximately at a point one-third of the way from the insertion of the mandible to the occipital border (in using this measurement it is well to note that the gena at the insertion of the mandible is deeply notched and the distance as given refers to a measurement from the bottom of this notch to the eye). The antennal scape in repose slightly surpasses the posterior fifth of the head. First funicular joint as long as the following three together, second joint approximately as broad as long, joints 3-7 broader than long. Club stout, the terminal joint three times as long as the penultimate.

Thorax with the humeral angles moderately rounded, the sides somewhat constricted at the mesoepinotal suture. Seen in profile the promesonotum is evenly and moderately convex except for the short and steep anterior face which descends to the neck. Mesoepinotal suture distinctly impressed. Epinotum in profile much higher than long, the two faces not clearly separated, together forming a steeply descending slope which is slightly convex in its upper half. The declivious face bears a broad and feeble median impression. Node of the petiole in profile low and very obtuse, scarcely higher than thick, the summit rather flattened, feebly convex and sloping slightly to the perpendicular posterior face. Anterior face longer than the posterior and steeply sloping forward, peduncle short and very thick with a long ventral lamella which ends anteriorly in an angular projection. Postpetiole in profile thicker and lower than the node of the petiole, the summit somewhat more evenly convex, virtually without a posterior face and with the anterior face extremely short. Seen from above both nodes are transversely oval in outline, the postpetiole being slightly wider and thicker than the node of the petiole. Edge of the first gastric segment truncate and with a strong concave impression at the base of the postpetiole.

Very smooth and shining with sparse, minute punctures which bear fine erect or sub erect hairs. Punctures on the thorax, petiolar nodes and abdomen much sparser than on the head, the hairs which they bear coarser and longer. Color, head and thorax rich golden yellow, the mandibles, anterior edge of the clypeus and the articulation of the petiole and postpetiole yellowish brown, the appendages, petiolar nodes and the abdomen pale yellow.

Pacheco and Mackay (2013) - Measurements (n=9). TL 2.04-2.28 (2.21); HL 0.540-0.600 (0.575); HW 0.504-0.570 (0.549); EL 0.030-0.042 (0.039); ED 0.030-0.036 (0.035); SL 0.390-00432 (00405); FSL 0.180-0.210 (0.196); CI 90.0-98.9 (95.5); SI 66.3-7404 (70.6); PL 0.120-0.150 (0.134); PW 0.174-0.186 (0.181); PI 66.7-80.7 (73.9); PPL 0.138-0.168 (0.147); PPW 0.192-0.216 (0.207); PPI 65.7-77.8 (71.4); WL 00420-00480 (0.473); PSL 0.042-0.066 (0.053); PSW 0.042-0.060 (0.051).

Concolorous yellow or orange; relatively large; head square; eyes round, at least two ommatidia; antennae, including minor segments 3-8 of funiculus long (0.19 mm total length); anterior margin of clypeus straight; clypeal carinae poorly defined; lateral and extralateral clypeal teeth absent; posterior border of head straight; notopropodeal suture well depressed, mesopleuron and metapleuron lacking striae; posterior propodeal margin rounded; propodeal spiracle large and round; petiole and postpetiole wide, petiolar peduncle lacking tooth, but with angle.

Not hairy, few erect and suberect hairs present, including on gaster, suberect hairs sparse throughout body surfaces.

Queen
Creighton (1930) - Length 2.6 mm. (Plate VIII, fig. 1 .)

Head very slightly longer than broad, the sides behind the eyes narrowed toward the occiput, occipital angles well marked not much rounded, the occiput flat. Clypeus feebly projecting, the anterior edge without teeth, the median lobe with a broad, shallow sulcus extending backwards to the elongated frontal lobes, the carinae represented only by the rounded lateral areas which bound the sulcus. Mandibles rather long and narrow, tridentate, the terminal tooth bent inward, the middle tooth small and rounded, the innermost tooth very large, consisting of two more or less fused teeth. Eyes of medium size, strongly convex, with their posterior border approximately at the middle of the side of the head. Antennae ten-jointed. Antennal scape in repose slightly surpassing the occipital border, first funicular joint almost as long as the following three together, joints 2-7 all slightly longer than broad, club rather short and strongly swollen, the last joint twice as long as the penultimate.

Thorax only slightly narrower than the head. The basal and declivious faces of the epinotum not sharply separated, virtually forming a single very declivious slope. Node of the petiole in profile obtusely rounded with a very long anterior face not sharply separated from the peduncle, the posterior face short and slightly sloping forward. Postpetiole in profile large and thick, only slightly lower than the node of the petiole. Seen from above the petiole is rather narrow, the postpetiole is strongly transverse and one and one-half times as broad as the node of the petiole. Anterior edge of the first gastric segment truncate. Just posterior to the base of the postpetiole the segment bears a conspicuous, concave and narrowly triangular impression.

Punctures of moderate size and fairly numerous. Hairs long, stout and erect. Color tawny yellow, the triangular area between the ocelli deep brown. Wings hyaline, the veins and stigma clear yellow.

Pacheco and Mackay (2013) - Large, golden yellow with lighter yellow gaster; head nearly quadrate with small punctures; mandibles with two teeth present basally; clypeal carinae absent; lateral teeth present as bumps, extralateral teeth absent; eyes large, extend past lateral border of head by 0.060 mm, approximately 50-100 ommatidia; notopropodeal suture weakly depressed; petiole wider than postpetiole viewed laterally; petiole round pyramidal; postpetiole circular as seen from above.

Fine erect hairs on all body surfaces; head, mesosoma, petiole and postpetiole and gaster are covered in erect and suberect hairs.

Male
Creighton (1930) - The male of succinea is only known only from Emery's very brief description a translation of which is given below :

"Length: 3.0 mm. Extremely smooth with sparse, very feeble punctures, abdomen almost impunctate. Black, legs piceous, articulations and tarsi reddish, antennae an obscure yellow-brown. Head strongly narrowed behind, eyes very large, antennal scape very short. Mesonotum with a profound anterior, longitudinal, median sulcus, punctate toward the middle.

Pacheco and Mackay (2013) - Measurements (n=1). TL 2.88; HL 0.438; HW 0.444; EL 0.210; ED 0.180; MOL 0.054; MOD 0.060; SL 0.168; FSL 1.08; CI 101; SI 38.4; PSL 0.066; PSW 0.060; PL 0.120; PW 0.210; PI 57.1; PPL 0.162; PPW 0.264; PPI 61.4; WL 0.720.

Large, golden yellow; head nearly quadrate with small punctures; mandibles with two teeth basally; clypeal carinae absent; lateral teeth present as bumps, extralateral teeth absent; eye large, extends 0.060 mm past border of head; antennae eleven segmented; notopropodeal suture weakly depressed, but does break sculpture of mesosoma; petiole wider than postpetiole viewed laterally; petiole rounded pyramidal, postpetiole with circular node viewed dorsally; petiole lacking subpeduncular process.

Hairy, erect and sub erect hairs present on all body surfaces.

Type Material
Pacheco and Mackay (2013) - Costa Rica, Jimenez (lectotype worker, 1 paralectotype worker, 1 paralectotype queen and 1 paralectotype male [here designated] ). Solenopsis succinea nicai Brazil, Sao Paulo (lhering von) 15.892 (7 cotypes workers ). Solenopsis inermiceps, Haiti, Grande Riviere. (M.Z.C. 1 Cotype worker 20432 ).

References based on Global Ant Biodiversity Informatics

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 * Cuezzo, F. 1998. Formicidae. Chapter 42 in Morrone J.J., and S. Coscaron (dirs) Biodiversidad de artropodos argentinos: una perspectiva biotaxonomica Ediciones Sur, La Plata. Pages 452-462.
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 * Luederwaldt H. 1918. Notas myrmecologicas. Rev. Mus. Paul. 10: 29-64.
 * Mirmecofauna de la reserva ecologica de San Felipe Bacalar
 * Pacheco J. A., and W. P. Mackay. 2013. The systematics and biology of the New World thief ants of the genus Solenopsis (Hymenoptera: Formicidae). Lewiston, New York: Edwin Mellen Press, 501 pp.
 * Santschi F. 1923. Solenopsis et autres fourmis néotropicales. Revue Suisse de Zoologie 30: 245-273.
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 * Vittar, F. 2008. Hormigas (Hymenoptera: Formicidae) de la Mesopotamia Argentina. INSUGEO Miscelania 17(2):447-466
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 * Wheeler W. M. 1905. The ants of the Bahamas, with a list of the known West Indian species. Bulletin of the American Museum of Natural History 21: 79-135.
 * Wheeler W. M., and W. M. Mann. 1914. The ants of Haiti. Bulletin of the American Museum of Natural History 33: 1-61.