Cuba, Honduras to southern Mexico
This species occurs in lowland wet to moist forest, from 200–575 m elevation. The recent collections are all from Winkler samples of sifted litter and rotten wood on the forest floor. Among the Project LLAMA specimens, seven are dealate queens and only two are workers, mostly from separate samples. This could reflect subterranean habits of the workers, with new queens dispersing up into the litter layer.
Worker (based on two workers from Tikal National Park, Guatemala). HW 0.38–0.39 (n=2); mandible with two closely-spaced, very short teeth at base, these basal teeth with broad confluent bases, either with distinct denticulate apices or completely confluent and forming a low lamina at base, a small denticle about mid-distance between basal teeth and base of subapical tooth, reclinate denticle at base of subapical tooth absent, subapical tooth shorter than width of mandible at base, only slightly longer than subapical tooth, intercalary teeth present but minute; labrum about as long as broad, with two long, bluntly triangular lobes, sinus between them deep, length of anterolateral lobe longer than or about equal to distance from base of sinus to transverse carina at base of labrum; anterior clypeal margin concave; erect setae on leading edge of scape stiff but narrow, hardly clavate, unlike the squamiform setae typical of many other species; arcuate promesonotal groove and metanotal groove weakly impressed; propodeal tooth right angled, infradental lamella thin, evenly and shallowly concave; first gastral tergite with sparse squamiform setae on posterior half, one specimen with five setae on posterior margin and three anteriorly, one specimen with seven and five, respectively.
Queen. HW 0.40–0.54 (n=5); mandible and labrum similar to worker; face shape similar to worker but with grooves and ridges more shallowly impressed; compound eye shorter than maximum width of scape, with 5-6 facets across longest axis; ocelli small, cuticle adjacent to ocelli marked with black pigment spots on evenly light brown background; shape of propodeal tooth, petiole and postpetiole similar to worker; shape of infradental lamella variable (see Comments); katepisternum and anepisternum large, convex, separated by broad groove; pubescence layer of abundant, short, curved setae covers mandible, face, scapes, legs, dorsal mesosoma and metasoma; abundant stiff erect setae on face, anterior edge of scape, side of head, dorsal mesosoma, dorsal gaster.
The male is unknown.
From Longino and Boudinot 2013:
Judging from the descriptions of Weber (1934) and Brown & Kempf (1960), and the geographic proximity of the Petén region to Cuba, we tentatively assign to R. weberi material from eastern Chiapas, across the Petén region, and south to north coastal Honduras. Quiroz-Robledo & Valenzuela-González (2010) identified a worker from Veracruz as R. weberi, which, based on the figure in the publication, also appears to belong here. Four queens from Tikal National Park and vicinity are very uniform, with HW 0.40-0.41 and the propodeal infradental lamella thin and very like the workers from this locality. One queen from near La Ceiba in Honduras has HW 0.44 and the infradental lamella is more expanded, forming two convexities below the tooth, separated by a narrow notch. Two queens from the Metzabok Reserve in eastern Chiapas are distinctly different. One of them has HW 0.44 and an infradental lamella like the queens from Guatemala. The other queen has HW 0.54 and infradental lamella like the queen from Honduras. Thus there is the potential for multiple cryptic species in R. weberi. LaPolla et al. (2006) report R. weberi from Guyana, but this identification is incorrect. The single specimen (examined) cannot be clearly assigned to genus: it has the habitus of the R. isthmica clade, but the mandible and labrum are like species in the genus Octostruma Forel, 1912.
Bolton, B. 1998. Monophyly of the dacetonine tribe-group and its component tribes (Hymenoptera: Formicidae). Bulletin of the Natural History Museum London (Entomology) 67:65-78.
Brown, W. L., Jr., Kempf, W. W. 1960. A world revision of the ant tribe Basicerotini. Stud. Entomol. (n.s.) 3:161-250.
Weber, N. A. 1934. Notes on neotropical ants, including the descriptions of new forms. Rev. Entomol. (Rio J.) 4:22-59.
Wilson, E. O. 1956. Feeding behavior in the ant Rhopalothrix biroi Szabo. Psyche (Camb.) 63:21-23.
Wilson, E. O., Brown, W. L., Jr. 1985 ("1984"). Behavior of the cryptobiotic predaceous ant Eurhopalothrix heliscata, n. sp. (Hymenoptera: Formicidae: Basicerotini). Insectes Soc. 31:408-428.
Found most commonly in these habitats: 4 times found in tropical moist forest, 2 times found in lowland wet forest, 1 times found in cloud forest, 1 times found in tropical moist forest at night, 1 times found in tropical rainforest
Collected most commonly using these methods or in the following microhabitats: 3 times MaxiWinkler, 4 times MiniWinkler, 1 times Night MiniWinkler, 1 times Winkler
Elevations: collected from 200 - 1300 meters, 414 meters average