Solenopsis metanotalis

Solenopsis metanotalis can be found in the La Plata basin in Argentina (Creighton 1930). We collected this species using pitfall traps at 1796 m in Mendoza, Argentina, in a creosote bush desert shrubland in fine sandy soils. It rained two nights before we placed the traps and the soil was wet to a 10 cm level. (Pacheco and Mackay 2013)

Identification
Pacheco and Mackay (2013) – Worker - This is a bicolored, reddish brown species with a darker brown gaster. The clypeus is concave between the well-developed lateral teeth that extend 0.480 mm past the anterior margin. The clypeal carinae are well developed and the extralateral teeth are absent. The eye is large with 40-50 ommatidia with eight facets at its maximum width. The dorsal edge of the mesosoma, when viewed in profile, is nearly a diagonal. The entire mesosoma is covered in horizontal striae. The propodeal posterior margin is angular with a ridge; the propodeal spiracle is small with a maximum diameter of 0.024 mm. The petiole is slightly wider than the postpetiole when viewed in profile and both have roughened sculpture. Queen - The queen is bicolored with the body and first tergite of the gaster reddish brown and the remainder of the gaster is darker brown. The lateral clypeal teeth extend 0.060 mm past the anterior margin of the clypeus. The extralateral teeth are absent. The head has coarse punctures, but smaller than the hairs that arise from them. The eye is large with approximately 188 ommatidia with a length of 0.225 mm and a width of 0.150 mm. The mesosoma is covered in horizontal striae and the petiole and postpetiole have roughened sculpturing. Male - The male is dark brown, nearly black, with brown appendages. The head is wider than long. The clypeus is convex and lacking carinae. The eyes are large and extend 0.120 mm past the lateral margin of the head. The head and mesosoma are covered in striae. The petiole is wider than the postpetiole in profile and both have roughened sculpturing. Both the petiole and postpetiole have nodes with pointy/sharp edges and both lack any tooth or flange ventrally.

Solenopsis metanotalis is easily recognized by its long clypeal teeth, large eyes and reddish brown, bicolored coloration. It may be confused with other members of the metanotalis subgroup and appears to be closely related to these sister species. However, S. metanotalis is distinguished from the other members of the nigella species complex and metanotalis subgroup by having the largest eyes and a fully striated mesosoma, with roughened sculpturing present on the petiole and postpetiole. These traits are variable in the other species, which are often lacking sculpturing on the pronotum or have less developed lateral clypeal teeth. Moreover, S. metanotalis is the largest species in this group.

Keys

 * Key to New World Solenopsis Species Complexes
 * Key to Solenopsis nigella species complex / Clave a las obreras del complejo Solenopsis nigella

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Bolivia, Brazil, Uruguay.

Nomenclature

 *  metanotalis. Solenopsis metanotalis Emery, 1896g: 86 (w.) ARGENTINA. Combination in S. (Euophthalma): Creighton, 1930b: 124. Senior synonym of argus, picturata, silvestrii: Pacheco & Mackay, 2013: 225.
 * argus. Solenopsis metanotalis var. argus Santschi, 1923c: 260 (w.m.) ARGENTINA. Junior synonym of metanotalis: Pacheco & Mackay, 2013: 225.
 * picturata. Solenopsis (Euophthalma) metanotalis var. picturata Santschi, 1931e: 276 (w.) ARGENTINA. Santschi, 1933e: 114 (q.). Junior synonym of metanotalis: Pacheco & Mackay, 2013: 225.
 * silvestrii. Solenopsis silvestrii Emery, 1906c: 120 (w.q.) URUGUAY. Combination in S. (Euophthalma): Creighton, 1930b: 137. Junior synonym of metanotalis: Pacheco & Mackay, 2013: 225.

Worker
Pacheco and Mackay (2013) - Measurements (n=4). TL 2.10-2.34 (2.24); HL 0.642-0.648 (0.645); HW 0.582-0.600 (0.596); EL 0.126-0.132 (0.128); ED 0.084; SL 0.438-0.450 (0.444); FSL 0.204-0.210 (0.207); CI 89.8-93.5 (92.3); SI 67.6-70.1 (68.8); PL 0.078-0.084 (0.083); PW 0.126-0.138 (0.134); PI 60.9-63.6 (61.8); PPL 0.150; PPW 0.192-0.210 (0.199); PPI 71.4-78.1 (75.3); WL 0.480; PSL 0.036; PSW 0.030.

Small, bicolored, reddish brown with darker brown gaster; head longer than wide, quadrate, with straight posterior margin; lateral clypeal teeth well developed, extend 0.480 mm past anterior clypeal margin; clypeal carinae well defined; extralateral teeth absent; eye large, with 40-50 ommatidia; frontal lobes vertically striated; scape long, but not reaching posterior lateral corner of head; minor funicular segments 3-8 long; mesosoma covered entirely with horizontal striae; notopropodeal suture well depressed, notch-like, groove breaks sculpture of mesosoma; propodeal posterior margin angular; propodeal spiracle small; petiole wider than postpetiole viewed laterally; both petiole and postpetiole heavily punctate with roughened sculpturing; petiolar node triangular with tooth ventrally; postpetiolar node oval-shaped when viewed dorsally.

Sparsely pilose, with few erect and suberect hairs covering all body surfaces; scape with numerous appressed hairs, none longer than maximum width; suberect and erect hairs of various lengths on mesosoma; sub erect hairs extend posteriorly on both petiole and postpetiole, with longest reaching 0.120 mm in length.

Queen
Pacheco and Mackay (2013) - Measurements (n=2). TL 4.44; HL 0.888-0.900 (0.894); HW 0.870; EL 0.222-0.228 (0.225); ED 0.156; MOL 0.054-0.060 (0.057); MOD 0.060; SL 0.600; FSL 0.300; CI 96.7-97.9 (97.3); SI 66.7; PSL 0.072; PSW 0.078; PL 0.144; PW 0.330; PI 43.6; PPL 0.270; PPW 0.540; PPI 50.0; WL 1.08.

Moderately large; bicolored body, head, mesosoma, first tergite of gaster reddish brown, remainder of gaster darker brown; head longer than wide, coarsely punctate, posterior margin straight; clypeal carinae well defined; lateral clypeal teeth well developed, extend 0.060 mm past anterior margin of clypeus; medial clypeal tooth present; extralateral teeth absent; frontal lobes vertically striated; eye large; medial ocellus small; scape reaches 2/3 length of head to posterior lateral corner; mesosoma completely horizontally striated; propodeal margin angulate, ridge like viewed laterally; propodeal spiracle small; petiole wider than postpetiole viewed laterally; petiolar node triangular, peduncle with well-developed flange ventrally; postpetiolar node globular with flange ventrally; petiole and postpetiole with roughened sculpturing.

Sparsely pilose, with erect and suberect hairs of various lengths scattered over body surfaces; head coarsely punctate, but with punctures smaller than hairs that originate from them; hairs on petiole and postpetiole curve posteriorly.

Male
Pacheco and Mackay (2013) - Measurements (n=2). TL 4.32; HL 0.642-0.648 (0.645); HW 0.792-0.810 (0.801); EL 0.312-0.336 (0.324); ED 0.246-0.258 (0.252); MOL 0.084; MOD 0.090-0.096 (0.093); SL 0.258-0.270 (0.264); FSL 1.20-1.32 (1.26); CI 123-125 (124); SI 40.2-41.7 (40.9); PSL 0.06; PSW 0.060; PL 0.120; PW 0.360; PI 33.3; PPL 0.150; PPW 0.438-0.450 (0.444); PPI 33.3-34.2 (33.8); WL 1.20.

Dark brown, nearly black with brown appendages; head wider than long, rounded posteriorly, striated; clypeus convex, lacking carinae; eyes large; mesosoma horizontally striated; petiole wider than postpetiole viewed laterally, with roughened sculpturing; petiolar and postpetiolar nodes angulate; petiolar peduncle and postpetiole lacking tooth or flange ventrally.

Abundantly hairy, with erect and suberect hairs of various lengths covering all body surfaces.