Eurhopalothrix gravis

Longino (2013): This species occurs in mature to second growth wet forest habitats. It is a lowland species, occurring from sea level to 1100 m in Central America. Many specimens are from Berlese and Winkler samples of sifted litter and rotten wood from the forest floor, but unlike many other species, specimens have also been found by direct search, usually isolated workers under loose bark of rotten wood. An alate queen was collected in a flight intercept trap in Belize, 19–28 August 2007 (P. W. Kovarik). Where it has been collected it is typically low density, occurring in less than 1% of Winkler samples, but one exception was a site at 1100 m elevation on the Barva Transect in Costa Rica, where it occurred in 8% of samples.

Distribution
Southern Mexico to Costa Rica; Brazil (Santa Catarina)?

Distribution based on Regional Taxon Lists
Neotropical Region: Belize, Costa Rica, Dominica, Guatemala, Honduras, Lesser Antilles, Mexico, Nicaragua, Puerto Rico, Venezuela.

Nomenclature

 *  gravis. Rhopalothrix (Rhopalothrix) gravis Mann, 1922: 40, fig. 19 (w.q.m.) HONDURAS. Wheeler, G.C. & Wheeler, J. 1955a: 117 (l.). Combination in Eurhopalothrix: Brown & Kempf, 1960: 211. Senior synonym of reichenspergeri: Brown & Kempf, 1960: 211.
 * reichenspergeri. Rhopalothrix reichenspergeri Santschi, 1923g: 1263 (w.) BRAZIL. Combination in Octostruma: Brown, 1949f: 92. Junior synonym of gravis: Brown & Kempf, 1960: 211.

Worker
Longino (2013) - HW 0.83–0.94, HL 0.75–0.83, SL 0.47–0.54, SLL 0.05–0.07, CI 110–115, SLI 10–14 (n=7). Labrum anterolateral gibbosities of basal portion developed as sharply right-angled, ventrally-directed teeth, apical portion short, flexed dorsally, distinctly bilobed, anterior lobes well separated; apex of each lobe with a fringe of very short translucent setae and 2 longer pointed translucent setae; mandible triangular, dorsal surface convex, minutely punctulate, dull, rounding into ventral surface; interior surface concave, smooth and shining; masticatory margin with two tooth rows, an outer row of 10 flattened, acute teeth, second and third tooth from base larger than other teeth; an inner row of 3 long needle-shaped teeth, behind outer teeth 3–6 and projecting beyond them, nearly 2x length of flanking outer teeth; scape with moderately developed basal lobe; scrobe deep, sharply delimited dorsally and ventrally, abutting deep antennal socket; surface of scrobe weakly foveolate anteriorly, smooth and shiny posteriorly; eye with about 5 ommatidia across greatest diameter; clypeus approximately planar, shallowly roughened, dull; juncture of clypeus and frons impressed; sides of head above eyes strongly angulate; surface of face uniformly convex, shallowly rugulose, anterior frons with moderately developed longitudinal medial carina; occipital carina indistinct; undersurface of head uniformly rugulose; postgenal suture a well-developed longitudinal trough.

Promesonotal profile evenly convex, posterior margin a short step dropping to sloping, flat dorsal face of propodeum; metanotal groove not impressed; dorsal and posterior faces of propodeum distinct, meeting at obtuse angle, dorsal face shorter than posterior face; propodeal spine laminar, translucent, triangular, acute, ventral margin curving into narrow infradental lamella that extends down posterior face to propodeal lobe; propodeal spiracle distinct, directed posteriorly; dorsal promesonotum rugulose; anterior pronotum, upper side of pronotum, anepisternum, dorsal and posterior faces of propodeum punctate; lower sides of pronotum, katepisternum, side of propodeum smooth, clean specimens with a pearly luster; with or without feeble transverse carinulae between propodeal spines.

Petiolar peduncle joins anterior face of petiolar node at rounded obtuse angle; petiolar node subquadrate, anterior face rounding into dorsal face and dorsal face rounding into posterior face; ventral margin of petiole with pronounced, acute anteroventral tooth; postpetiole low and broad, with a shallow longitudinal sulcus dorsally; first gastral sternite lacking anterior sagittal keel; petiole, postpetiole, first gastral tergite covered with dense, small, puncta, interspaces less than or equal to width of puncta; first gastral sternite similar, but puncta and interspaces larger.

Dorsal surface of scape covered with uniform short, appressed, flattened setae; leading edge of scape with projecting setae, shortest near apex, gradually lengthening to longest on basal lobe; ground pilosity uniformly distributed across face, frontal lobes, and clypeus; ground setae on posterolateral face similar to those on scapes, ground setae on medial face and clypeus thinner; undersurface of head with ground setae like those on posterolateral face; projecting specialized setae spatulate, about 3x longer than wide, much larger than ground pilosity and highly differentiated from it, full complement 18, with curved anterior row of 8, transverse median row of 4, and posterior row of 6 on vertex margin; ground setae similar to those on posterolateral face abundant on promesonotal dorsum, dorsal half of propodeal spines, dense on dorsa of petiolar node and postpetiole, much sparser on first gastral tergite; 3 pairs projecting spatulate setae on promesonotum; legs with dense, strongly flattened, appressed to decumbent setae on apices of femora, posterior face of foretibia, entire midtibia, anterior face of hindtibia, somewhat sparser on other surfaces; apex of foretibia with 1 larger spatulate seta, apices of mid and hind tibia with 2; basitarsus and remaining tarsomeres with abundant, spatulate setae; two large spatulate setae on hind margin of dorsal face of petiolar node; row of 4 spatulate setae on hind margin of postpetiole, median pair smaller than lateral pair; specialized setae of first gastral tergite spatulate, full complement 4 pairs in two longitudinal rows.

Color orange brown.