Solenopsis thoracica

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Solenopsis thoracica
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Solenopsidini
Genus: Solenopsis
Species complex: fugax
Species: S. thoracica
Binomial name
Solenopsis thoracica
Santschi, 1923

Nothing is known about the biology of Solenopsis thoracica.

Identification

A New World thief ant that is a member of the fugax species complex

Pacheco and Mackay (2013) - Minor worker - The minor is concolorous yellow and the eye has seven ommatidia. All four clypeal teeth are present and well developed. The minor funicular segments 3-8 are long for thief ants at 0.240 mm in total length. The petiolar peduncle has a well-developed tooth ventrally. Major worker - This is one of very few species that is dimorphic. The major worker is golden brown and large in total length (3.00 mm). The head is coarsely punctate. All four clypeal teeth are present and well developed. The minor funicular segments 3-8 are long at 0.276 mm. The eye is large with 8-10 ommatidia. The other characters are similar to those of the minor (i.e. metapleuron horizontally striated and petiolar peduncle with well-developed tooth ventrally). Male - The male is large at 5.00 mm in total length. The head is much wider than long, giving it an oblong appearance. The head is covered in striae that follow the outline of the head. The anterior clypeal border is straight, lacking teeth. The propodeum has horizontal striae basally and roughened sculpturing above the spiracle.

Solenopsis thoracica is one of the few species that is dimorphic. It is further distinguished as it is a relatively large thief ant as both the minor worker and the major are about 2 and 3 mm in total length separating them from all other dimorphic species of thief ants.

We recognize it as a valid species as the male is much larger than that of Solenopsis patagonica (5 mm total length, versus 3 mm in S. patagonica). Solenopsis patagonica appears to be monomorphic. The minor worker of S. thoracica can be separated from that of S. patagonica as it is much larger (total length 2.16 mm versus 1.6 mm in S. patagonica).

Keys including this Species

Distribution

Known only from the type locality.

Distribution based on Regional Taxon Lists

Neotropical Region: Chile (type locality).


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Queens have yet to be collected.

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • thoracica. Solenopsis thoracica Santschi, 1923c: 261 (w.m.) CHILE. Junior synonym of patagonica: Kusnezov, 1960b: 338. Revived from synonymy: Pacheco & Mackay, 2013: 338.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Pacheco and Mackay (2013) - Major Measurements (n=3). TL 2.88-3.24 (3.04); HL 0.750-0.780 (0.762); HW 0.660-0.720 (0.680); EL 0.066-0.078 (0.074); ED 0.048-0.060 (0.056); SL 0.540-0.552 (0.544); FSL 0.240-0.282 (0.260); CI 87.3-92.3 (89.2); SI 70.8-72.0 (7104); PL 0.120; PW 0.240; PI 50.0; PPL 0.174-0.180 (0.176); PPW 0.210-0.240 (0.230); PPI 72.5-82.9 (76.8); WL 0.600-0.630 (0.610); PSL 0.048-0.054 (0.052); PSW 0.048.

Large; concolorous golden brown; head quadrate, longer than wide, coarsely punctate; lateral and extralateral clypeal teeth well developed; clypeal carinae weakly defined; frontal lobes vertically striated; scapes long, reaching ¾ length of head; minor funicular segments 3-8 long; eyes large, 8-10 ommatidia; pronotum coarsely punctate, smooth and shiny between punctures; mesopleuron smooth and shiny; metapleuron horizontally striated; posterior propodeal margin with angled slope viewed laterally; petiole robust, wider than postpetiole viewed laterally; petiolar peduncle with well-developed tooth ventrally.

Abundantly hairy, pilosity white and yellow; erect and suberect hairs covering all body surfaces; hairs on mesosoma long (many 0.150 mm); hairs on petiole and postpetiole curve posteriorly.

Minor Measurements (n=2). TL 2.16; HL 0.570-0.600 (0.585); HW 0.480-0.540 (0.510); EL 0.060-0.078 (0.069); ED 0.048-0.060 (0.054); SL 0.414-0.438 (0.426); FSL 0.180-0.210 (0.195); CI 84.2-90.0 (87.1); SI 72.6-73.0 (72.8); PL 0.090; PW 0.180; PI 50.0; PPL 0.120; PPW 0.180; PPI 66.7; WL 0.420-0.450 (0.435); PSL 0.048; PSW 0.048.

Moderately large; concolorous yellow; head longer than wide, coarsely punctate; lateral clypeal teeth well developed, extralateral teeth well developed; clypeal carinae well defined; frontal lobes vertically striated; scapes long, do not reach posterior margin of head; minor funicular segments long; eyes, black, relatively large, with seven ommatidia; pronotum and mesopleuron smooth and shiny; metapleuron horizontally striated; posterior propodeal margin with slightly angled slope viewed laterally; petiole wider than postpetiole viewed laterally; petiolar node extends laterally, peduncle with well-developed tooth ventrally; postpetiolar node globose, lacking tooth or flange ventrally.

Abundantly hairy, pilosity yellow; head with numerous erect hairs (0.054 mm); hairs on mesosoma long (many 0.120 mm); hairs on petiole and postpetiole curve posteriorly.

Male

Pacheco and Mackay (2013) - Measurements (n=1). TL 5.04; HL 0.660; HW 0.720; EL 0.282; ED 0.240; MOL 0.072; MOD 0.078; SL 0.282; FSL 1.44; CI 109; SI 42.7; PSL 0.096; PSW 0.09; PL 0.180; PW 00408; PI 44.1; PPL 0.360; PPW 00450; PPI 80.0; WL 1.56.

Large; concolorous dark brown; head wider than long, oval/oblong; fully covered in striae that follow contour of cephalic capsule; anterior clypeal margin straight, clypeal carinae present; eyes large; medial ocellus small; roughened sculpturing next to sutures on mesosoma; metapleuron horizontally striated basally, with roughened sculpturing above spiracle; petiole wider than postpetiole viewed laterally; petiolar node extends laterally (viewed from above), lacking tooth or flange ventrally.

Moderately hairy, pilosity yellow; long erect and suberect (0.300 mm) scattered on head, mesosoma, petiole and postpetiole.

Type Material

Pacheco and Mackay (2013) - Sammlung Dr. F. Santschi, Kairouan, Chile, Cayutue, Lago Todos los Santos (Wolfhugel) (6 unknown symbol, 1 worker types Naturhistorisches Museum, Basel), Chile, Wm. M. Wheeler. (1 unknown symbol, 1 male types, M.C.Z. Type 1-2, 20944 Museum of Comparative Zoology).

References