Leptogenys gorgona

Identification
Lattke (2011) - Head rectangular in full-face view; eye length equal to one-fourth lateral cephalic margin; length of antennal segments II – IV approximately 2 × their respective length. Petiolar node elongate in dorsal view, anterior margin broadly convex and half the width of posterior margin, posterior margin straight, lateral margins straight to slightly concave.

A member of the pusilla species group. This ant can be easily confused with Leptogenys pusilla on account of its similar size and general characteristics but the following traits can be used to separate the two. The dorsal propodeal margin in lateral view curves onto the declivitous margin, differing from the blunt angle of L. pusilla. L. gorgona has a better defined metanotal groove, a more elongate node and head, and relatively larger eyes. L. gorgona can also be confused with the sympatric Leptogenys quadrata because of the elongate head and node, but L. quadrata is considerably larger, and lacks propodeal armature.

Distribution
This taxon is known from northwestern Colombia – eastern Ecuador.

Castes
Queen, male. Unknown.

Nomenclature

 *  gorgona. Leptogenys gorgona Lattke, 2011: 191, fig. 45 (w.) COLOMBIA.

Worker
Metrics (n = 3) : HL 0.80 – 0.87; HW 0.48 – 0.50; ML 0.32 – 0.35; EL 0.10 – 0.15; SL 0.67 – 0.75; PW 0.45 – 0.48; WL 1.14 – 1.22; PH 0.40 – 0.45; PL 0.45 – 0.48; DPW 0.27 – 0.27 mm. CI 0.58 – 0.61; MI 0.66 – 0.70; OI 0.21 – 0.30; SI 1.38 – 1.50; LPI 0.89 – 0.93; DPI 0.55 – 0.59.

Head rectangular in full-face view; lateral margin broadly convex; posterior cephalic margin weakly concave, almost straight; median clypeal lobe triangular, apex acutely pointed; lateral lobe narrow, inconspicuous; eye broadly convex in cephalic full-face view; head widest posterior to compound eyes. Scape surpasses posterior cephalic border by 2 apical widths; basal funicular segments approximately of same length; length of antennal segments II – IV approximately 2 × their respective lengths. Mandibular basal margin broadly sinuate, row of 3 stiff hairs present basad; masticatory margin short with blunt apical tooth; mandibular dorsum mostly smooth and shining with scattered punctulae; mandible of same width in oblique ventral view. Cephalic dorsum mostly smooth and shining with sparse punctulae.

Dorsal mesosomal margin mostly continuous in lateral view, metanotal groove broad and shallow; straight to weakly convex, pronotal and propodeal dorsal margin each broadly convex; declivitous margin of propodeal declivity convex, with blunt, modest triangular lobe at spiracular height; mesosomal side smooth and shining, mesometapleural suture distinctly impressed, scrobiculate; metapleural-propodeal suture absent; propodeal spiracle oval with opening directed posterolaterally, weakly oblique; shallow depression located between spiracle and propodeal lobe; mesosomal dorsum smooth and shining, propodeal declivity with 4–5 transverse striae. Mesopleuron with anteroventral carina widest anterad; mesonotum 2.5 × wider than long in dorsal view, posterior margin straight.

Petiole node subquadrate in lateral view, slightly inclined anterad; anterior and posterior margins vertical, anterior margin less than half the height of posterior margin; node highest posterad, dorsal margin convex, without sharp lateral edges. Subpetiolar process rectangular in lateral view, with anterior margin shorter than posterior margin. Node elongate in dorsal view, anterior margin broadly convex and half the width of posterior margin, posterior margin straight, lateral margins straight to slightly concave. Transverse section of node at mid-length roughly V-shaped with straight lateral margins. Anterodorsal postpetiolar margin continuously rounded in lateral view or with anterior margin more broadly convex than dorsal margin; constriction between abdominal segments III – IV well marked. Body color ferruginous to dark brown; mandibles, legs, and antenna brownish-yellow. Body with scattered erect and semi-erect hairs, appressed pilosity wanting. Coxae mostly smooth and shining; metacoxal dorsum with posterior rounded crest basad; tibial apices usually lacking setae, mesotibia occasionally with seta.

Type Material
Holotype worker. Colombia, Valle, Anchicayá, 200 m, 17. – 19.vi.1971, W.L. Brown leg. One worker deposited in. – Paratypes. Seven workers from the same series as holotype. 5w deposited in MCZC, 1w, 1w.

Etymology
The species name is derived from an island included within the geographic range of the species: Isla La Gorgona along the southwestern Colombian coast.