Linepithema hirsutum

Specimens of L. hirsutum were collected at 640–671 m with pitfall traps, Winkler traps, and hand collection in a tropical rainforest in the Reserva Natural El Pangán, Colombia. The yearly temperature range of Pangán is between 12–24°C.

Identification
Escarraga and Guerrero (2016) - Many erect setae on body; pronotum with more than 10 erect setae; surface anterior to the metapleural gland orifice lacking pubescence; body color yellow.

Linepithema hirsutum is the only species of Linepithema with numerous erect setae throughout the body surface. Linepithema tsachila has no more than eight erect setae on the pronotum, while L. hirsutum has 12–24. Variation in the number of erect setae was found; larger specimens had more and longer setae, and smaller specimens had shorter and fewer setae. We propose that this species is in the L. fuscum-group, on account of the lack of metapleural pubescence and the presence of a well-developed clypeal groove.

Distribution based on Regional Taxon Lists
Neotropical Region: Colombia.

Nomenclature

 *  hirsutum. Linepithema hirsutum Escarraga & Guerrero, 2016: 450, figs. 1A, 1B, 3 (w.) COLOMBIA.

Worker
Holotype. HL 0.70, HW 0.66, MFC 0.16, SL 0.64, FL 0.62, LHT 0.64, ES 1.4, PW 0.44, CI 94, SI 91, CDI 24, IO 20.

Worker. (n= 31) HL 0.56–0.70, HW 0.40–0.68, MCF 0.12–0.16, SL 0.54–0.70, FL 0.50–0.62, LHT 0.46–0.70, ES 0.96–1.68, PW 0.36–0.48, CI 67–97, SI 91–107, CDI 21–36, IO 15–25.

Head longer than wide (CI 67–97), lateral margins of head convex, posterior margin almost straight to slightly concave (Fig. 1A). In full-face view, head reaches widest point behind compound eyes level. Compound eye size small to moderate (OI 15–25), with 38–40 ommatidia. Antennal scape short to moderately long (SI 91–107), exceeding posterior margin of the head by almost 1/4 its scape length. Frontal carinae narrowly to broadly separated (CDI 21–36). Maxillary palps of moderate length, below ½ HL, segment 6 shorter to somewhat same length than segment 2. Pronotum and anterior portion of mesonotum form continuous convexity. Mesonotal dorsum usually with slight medial impression. Metanotal groove moderately impressed. In lateral view, propodeum frequently high, with dorsal face rounded to straight (Fig. 1B). Petiolar scale sharp and anteriorly inclined. Head with numerous erect setae on the lateral and posterior margins; more than 10 erect setae on head dorsum, excluding those on clypeus. Pronotum with 12–24 erect setae, usually 2–4 setae are longer than rest of pronotal setae. Dorsum of the mesonotum and propodeum with 10–20 short erect setae. Petiolar scale with 4–8 erect setae. Gastral tergites with numerous erect setae shorter than those on the mesosoma. Legs and antennal scape with numerous short erect setae. Dorsal surface of head and mesosoma dull to moderately shining; sculpture on scapes shagreened or granular. Pubescence dense on head, mesosomal dorsum, anterior face of petiolar scale, and gastric tergites 1–4. Meso- and metapleura smooth and shiny, lacking pubescence.

Type Material
Holotype worker. Narino: Barbacoas, Reserva Natural El Pangán, 1º21’49”N 78º4’45”W, 640 m, manual collection, 28.vii.2006, A. Miranda and O. Reyes, deposited in (IAvH-E 95404). Paratypes. Same data as holotype, deposited in CCBUMAG (1w, CBUMAG 06968), IAvH (35w), and the California Academy of Sciences (1w, CASENT0179544).

Etymology
From Latin hirsutus because of the many erect hairs on the body surface. This name is a neutral noun.