Solenopsis melina

This species nests in the loose sandy gypsum soil of White Sands National Monument and in similar scrubby Chihuahuan Desert habitats of Lake Lucero. Brood was collected in a nest in July, and queens were loose on ground in July, suggesting a mating flight had occurred recently. In California they are found in the transition from shrubland to pine forest in rocky soils. Myrmecophila sp. crickets were found in a nest. Specimens were found in the nests of Pogonomyrmex montanus at the 110 cm level and at unspecified levels (3 additional nests) and in a nest of Pogonomyrmex subnitidus. (Pacheco and Mackay 2013)

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

Pacheco and Mackay (2013) – Worker - The worker is small and honey yellow colored. The head has coarse cephalic punctures. The antennal club is long at 0.300 mm in total length. The lateral clypeal teeth are well developed, but the extralateral teeth are present as angles. The petiole and postpetiole are robust with a tooth on the subpeduncular process. Queen - The queen is also honey yellow in color. What is unique to the queen is that the frontal lobes contain vertical striae that curve laterally then anteriorly towards the anterior clypeal margin. Additionally the propodeum, petiole and postpetiole are covered in horizontal striae.

The worker of Solenopsis melina is similar to Solenopsis molesta, however can be separated from this widely distributed North American species by the presence of vertical striae on the frontal lobes. The head is more quadrate with the CI ranging from 85-93 (81-85 in S. molesta). Solenopsis melina has more robust petiolar and postpetiolar nodes. The queen of S. melina is unique in having cephalic striae which extends from the frontal lobes laterally past the antennal insertion, which curve anterior toward the clypeal margin. This feature is unknown within other species of the molesta and fugax complexes in the New World.

Keys

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

Distribution
White Sands National Monument and nearby Lake Lucero New Mexico and the mountains of southern California.

Distribution based on Regional Taxon Lists
Nearctic Region: United States.

Biology
Pacheco and Mackay (2013) - It is possible that S. melina is a specialist parasite of harvester ants of the genus Pogonomyrmex, as most specimens were collected within harvester ant nests. Those in the vicinity of White Sands National Monument were not specifically associated with harvester ants, but several species of Pogonomyrmex occur in the area (Pogonomyrmex californicus, Pogonomyrmex desertorum, Pogonomyrmex maricopa).

Castes
Males have yet to be collected.

Nomenclature

 *  melina. Solenopsis melina Pacheco & Mackay, 2013: 222, figs. 172-175, map 42 (w.q.) U.S.A.

Worker
Measurements (n=6). TL 1.44-1.68 (1.59); HL 0.444-0.510 (0.469); HW 0.360-0.408 (0.382); EL 0.036-0.042 (0.040); ED 0.030; SL 0.300-0.360 (0.328); FSL 0.132-0.156 (0.143); CI 80.0-83.3 (81.3); SI 67.6-71.3 (69.8); PL 0.072-0.084 (0.076); PW 0.102-0.162 (0.126); PI 51.9-70.6 (61.2); PPL 0.090-0.120 (0.109); PPW 0.120-0.174 (0.145); PPI 68.2-90.0 (75.9); WL 0.300-0.360 (0.340); PSL 0.030-0.042 (0.038); PSW 0.024-0.036 (0.029).

Small; concolorous honey yellow; head rectangular, longer than wide, coarsely punctate, sides slightly convex, posterior border nearly straight (slightly concave); lateral clypeal teeth well developed, extralateral teeth angulate; clypeal carinae well dermed; frontal lobes vertically striated; eyes, black, small, with 3-5 ommatidia; scape long, does not reach posterior border of head; minor funicular segments 3-8 long; club long at 0.300 mm in total length; pronotum coarsely punctate, smooth and shiny between punctures; mesopleuron smooth and shiny; posterior propodeal margin angulate viewed laterally; metapleuron horizontally striated; petiole robust, node triangular, peduncle with tooth ventrally; postpetiole robust, node globose, lacking tooth or flange ventrally.

Abundantly pilose, pilosity yellow; erect and suberect hairs of various lengths covering all body surfaces; hairs on mesosoma, petiole and postpetiole up to 0.120 mm in total length.

Queen
0.042-0.048 (0.045); MOD 0.060; SL 0.390; FSL 0.228-0.240 (0.234); CI 83.3; SI 57.0; PSL 0.048; PSW 0.054; PL 0.120; PW 0.300; PI 40.0; PPL 0.264; PPW 0.318; PPI 83.0; WL 0.840.

Moderately large; concolorous honey yellow; head rectangular, longer than wide, coarsely punctate; lateral clypeal teeth short but well developed, extralateral teeth small, well developed; clypeal carinae well developed; frontal lobes laterally and posteriorly from clypeal margin with striae which follow contours of head; scape short, reaches medial ocellus; medial ocellus round, large; eye large, black; pronotum coarsely punctate, smooth and shiny between punctures; side of metapleuron horizontally striated basally, with roughened sculpturing above spiracle; petiole and postpetiole horizontally striated; petiolar peduncle with flange ventrally.

Abundantly hairy, pilosity yellow; pronotum with numerous erect hairs of relatively equal length (0.090 mm); suberect hairs on petiole and postpetiole long (0.120-0.150 mm), curve posteriorly.

Type Material
Holotype worker and 9 paratype workers, New Mexico, Otero County, White Sands National Monument, 31-v-1992, 25-vii-1992, W. Mackay #'s 15945, 16054, 16059.

Etymology
From Latin, melinus, meaning honey-colored, referring to the color of the worker and queen.

References based on Global Ant Biodiversity Informatics

 * 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.