Octostruma leptoceps

This is known from a single worker collected in mesophyll cloud forest at 1290 m elevation. The specimen was in a sample of sifted leaf litter from the forest floor.

Identification
Basal five teeth of mandible acute; labrum triangular with straight, evenly converging sides, anterior lobes converging and confluent at apex, such that labrum apex is blunt but not distinctly bilobed; head very narrow, CI 94. (Longino 2013)

Distribution based on Regional Taxon Lists
Neotropical Region: Honduras.

Castes
Known only from the worker caste.

Nomenclature

 *  leptoceps. Octostruma leptoceps Longino, 2013: 38, figs. 1A, 5H, 28, 43 (w.) HONDURAS.

Worker
HW 0.68, HL 0.73, WL 0.87, CI 94 (n=1); Labrum sides straight, strap-like lateral portions converging from base to apex, apex bluntly rounded, not bilobed; mandible triangular, in profile view with mandible closed, base in same plane as clypeus, evenly curved downward toward apex; mandibles closed on holotype, but basal teeth visible, acute, tooth 1 continuous with basal rim of dorsal surface; dorsal surface of mandible roughened; ventral surface flat, smooth and shining; interior surface concave, smooth and shining; scape with pronounced anterobasal lobe, dorsal surface smooth, matte; clypeus with broad, shallow emargination anteriorly; clypeus smooth, sublucid, with sparse puncta; face uniformly irregularly rugose; frontal carinae faint, nearly obsolete; antennal socket deep, dorsal rim of socket continuous with pronounced dorsal margin of antennal scrobe; antennal scrobe deep, strongly delimited dorsally, posteriorly, and ventrally with sharply defined thin cuticular rim; compound eye small, circular, composed of about 7 ommatidia; distinct carina extends from ventral margin of antennal socket across floor of scrobe to compound eye; scrobe floor matte; vertex margin anterior to occipital carina smooth, matte (top of head, not visible in face view); occipital carina extends anteriorly on ventral surface of head about to level of compound eye; postgenal suture visible as impressed line on undersurface of head; undersurface rugulose.

Promesonotum moderately convex in profile, promesonotal suture moderately impressed; metanotal groove not impressed; propodeum with distinct dorsal and posterior faces; dorsal face weakly convex; propodeal spines well-developed, acute, laterally flattened, extending ventrally as thin carinae; propodeal spiracle somewhat protruding, located below propodeal spine, not quite abutting posterior margin, diameter about equal to width of base of propodeal spine; all surfaces of mesosoma matte; entire promesonotum irregularly rugose, with similar sculpture to face; mesopleuron and side of propodeum confluent; entire mesopleuron and propodeum smooth.

Petiole in profile with peduncle differentiated from node, node with distinct anterior face; posterodorsal face of node an even convexity; anteroventral margin with anteriorly-directed tooth subtended by short posterior flange; postpetiole low, broad, weakly crescent-shaped in dorsal view; dorsum of petiolar node and postpetiole punctatorugose; first gastral tergite and sternite densely punctate, interspaces smooth and shining, tergal puncta smaller posteriorly; first gastral sternite strongly convex, with prominent blunt medial keel.

Anterior labral lobe with radiating tuft of soft, thick, translucent, capitate setae of unequal length projecting from apex; each larger mandibular tooth with fully appressed seta running length of tooth; anterior margin of scape with about nine stiff clavate setae; clypeus, face, promesonotal dorsum, petiolar node, and dorsal postpetiole with conspicuous, yellow, appressed ground pilosity of long, thin setae; face of holotype appears largely devoid of erect setae but specimen may have lost setae; a single spatulate seta present on one lateral vertex margin, and what may be a seta near medial vertex margin; mesosomal dorsum lacking erect setae; mesotibia with conspicuous ground pilosity, about 5 spatulate setae of variable length at apex; petiole and postpetiole lacking erect setae; first gastral tergite lacking erect setae, ground pilosity fully appressed, sparse (length of setae less than distance between them); first gastral sternite with abundant spatulate setae clustered on posterior half, anterior half devoid of setae.

Color dark brown.

Type Material
Holotype worker: Honduras, Cortés: PN Cusuco, 15.48940, -88.23621, ±20 m, 1290 m, mesophyll forest, ex sifted leaf litter, 30 May 2010 (LLAMA, Wa-C-06-2-12), unique specimen identifier CASENT0617645.

Etymology
The name refers to narrow head relative to other species. It is a noun in apposition and thus invariant.

References based on Global Ant Biodiversity Informatics

 * Longino J. T. 2013. A revision of the ant genus Octostruma Forel 1912 (Hymenoptera, Formicidae). Zootaxa 3699(1): 1-61.
 * Longino J. T. L., and M. G. Branstetter. 2018. The truncated bell: an enigmatic but pervasive elevational diversity pattern in Middle American ants. Ecography 41: 1-12.