Eurhopalothrix schmidti

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Rhopalothrix schmidti
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Eurhopalothrix
Species: E. schmidti
Binomial name
Eurhopalothrix schmidti
(Menozzi, 1936)

Eurhopalothrix schmidti inbiocri001280623 p 1 high.jpg

Eurhopalothrix schmidti inbiocri001280623 d 1 high.jpg

Specimen Labels

Longino (2013) - This species inhabits moist to wet montane forest. The types were collected as a nest series in Costa Rica's Central Valley, in the early 1900's, at a site that is now near the San José airport and long since developed. All recent collections are from Winkler samples of sifted litter and rotten wood from the forest floor. It is known from 1100–1670 m elevation. In Monteverde, in the Cordillera de Tilarán, it has a sharply parapatric distribution with Eurhopalothrix ortizae and may hybridize there (see Comments under Eurhopalothrix ortizae).


Mandible with single tooth row; face with 20 specialized spatulate setae; ground pilosity of face short, flattened, appressed, sparse, extending across entire face, including median area and frontal lobes; face punctatorugose, evenly convex (lacking longitudinal median impression); pronotum with 1 pair spatulate setae, lacking on mesonotum; first gastral tergite with full complement 4 pairs spatulate setae in two longitudinal rows, posterior row often flanked by additional pair. Similar to Eurhopalothrix circumcapillum, Eurhopalothrix megalops, Eurhopalothrix ortizae, Eurhopalothrix oscillum, Eurhopalothrix semicapillum. (Longino 2013)

Keys including this Species


Latitudinal Distribution Pattern

Latitudinal Range: 10.3043° to 9.5534501°.

Tropical South

Distribution based on Regional Taxon Lists

Neotropical Region: Costa Rica (type locality), Panama.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


Little is known about the biology of most species in this genus. Nests are rarely found, and queens and males have not been collected for many species. Longino (2013) summarized their biology "Eurhopalothrix specimens are encountered almost exclusively in samples from mass extraction techniques that recover small arthropods in sifted litter, rotten wood, and soil. Densities, at least in the northern Neotropics, are usually low, with workers occurring in < 10% of quantitative samples of 1 m2 litter plots, but occasionally may reach densities as high as 40% of samples. Live colonies of Old World Eurhopalothrix were observed by Wilson (1956) and Wilson and Brown (1984), and a Costa Rican colony of Basiceros manni was observed by Wilson and Hölldobler (1986). All basicerotines, including Eurhopalothrix, are thought to be predators in tropical leaf litter, relying on stealth or sit-and-wait techniques. Sampled specimens are often coated with a thin layer of clay, especially on the face, which is thought to function as camouflage, enhancing crypsis (Hölldobler & Wilson, 1986). Highly specialized spatulate setae may be instrumental in acquisition and adherence of the clay layer (Hölldobler & Wilson, 1986)."




The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • schmidti. Rhopalothrix (Rhopalothrix) schmidti Menozzi, 1936c: 82, fig. 1 (w.q.l.) COSTA RICA. Junior synonym of gravis: Brown & Kempf, 1960: 211. Revived from synonymy: Longino, 2013: 137.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.



Longino (2013) - HW 0.75–0.80, HL 0.71–0.77, SL 0.42–0.47, SLL 0.05, CI 102–106, SLI 11–12 (n=5). Labrum anterolateral gibbosities of basal portion developed as sharply right-angled, ventrally-directed teeth, apical portion elongate, flexed dorsally, relatively narrow, with a notch at apex, such that apex shallowly bilobed; apex with a fringe of short, non-capitate translucent setae; mandible triangular, dorsal surface convex, smooth and shining apically, grading to punctate basally, rounding into ventral surface; interior surface concave, smooth and shining; masticatory margin a single row of 11 flattened acute triangular teeth; scape with weakly developed basal lobe; scrobe deep, sharply delimited dorsally and ventrally, abutting deep antennal socket; surface of scrobe faintly foveolate; eye small, about 6 ommatidia across greatest diameter; clypeus approximately planar, uniformly punctate, dull; sides of head above eyes moderately angulate; surface of face uniformly convex and uniformly punctatorugose; occipital carina indistinct; undersurface of head uniformly punctate; postgenal suture a well-developed longitudinal trough, darker than surrounding cuticle.

Promesonotal profile somewhat flat-topped, meeting flat dorsal face of propodeum at obtuse angle; metanotal groove a broad shallow trough, often delimited posteriorly by low but distinct rim that delimits dorsal face of propodeum, groove in dorsal view with parallel longitudinal rugae; 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 rounding into very narrow infradental lamella that extends down posterior face to propodeal lobe; populations in Cordillera de Talamanca with relatively narrow spines that meet infradental lamella at nearly right angle; population from Cordillera de Tilarán with broader, more triangular spine that meets infradental lamella at obtuse angle; propodeal spiracle small, directed posteriorly in small concavity between base of propodeal spine and dorsum of metapleural gland bulla; all of mesosoma except posterior face of propodeum uniformly punctate with smooth interspaces; posterior face of propodeum smooth to very faintly sculptured; no transverse carinae between bases of propodeal spines; puncta on promesonotum larger than those on katepisternum and side of propodeum; interspaces sublucid on promesonotum, more matte on katepisternum and side of propodeum.

Petiolar peduncle joins anterior face of petiolar node at rounded obtuse angle; anterior face of node meets sloping flat dorsal face at rounded right angle; posterior face of node very short; ventral margin of petiole with short, acute, anteroventral tooth; postpetiole low and broad, with a broad longitudinal sulcus dorsally; first gastral sternite lacking anterior sagittal keel; petiole, postpetiole, and gaster densely punctate; interspaces between puncta on first gastral tergite similar in width to puncta, sublucid; sculpture on first gastral sternite similar but puncta and interspaces larger.

Dorsal surface of scape covered with uniform short, appressed to decumbent, flattened setae; leading edge of scape with projecting spatulate setae; ground pilosity on clypeus obsolete; ground pilosity of face similar in size and shape to ground setae on dorsal scape, appressed, sparse, separated from each other by distance greater than or equal to length, more or less uniformly distributed across entire face, including frontal lobes (becoming smaller on frontal lobes); projecting specialized setae spatulate, erect and highly differentiated from ground pilosity, full complement typically 20, with curved anterior row of 8, transverse median row of 6 (the outermost at outermost angles of sides of head), and posterior row of 6 on vertex margin; ground pilosity obsolete on dorsal mesosoma and metasoma; typically one pair of projecting spatulate setae on pronotum, similar to those on face; legs with ground pilosity denser and more flattened than that on face, dense on apices of femora, dorsal and anterior faces of mid and hind tibia, dorsal and posterior face of foretibia, sparser to absent elsewhere; apex of foretibia with 1 larger spatulate seta, apices of mid and hind tibia with 2; basitarsus with 3–5 pairs suberect clavate setae, remaining tarsomeres each with pair of suberect clavate setae, tarsal setae smaller on foretarsus than on mid and hind tarsus; 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, posterior pair often flanked by additional pair (4 pairs along posterior border of tergite).

Color dark brown.


Longino (2013) - HW 0.78, HL 0.76, SL 0.47, SLL 0.05, CI 103, SLI 11 (n=1). Similar to worker in most respects; ocelli present; compound eye much larger than worker eye; anepisternum separated from katepisternum by U-shaped groove; metapleuron separated from propodeum by broad U-shaped groove; erect setae all weakly clavate, sublinear, not spatulate like worker setae; face with number and distribution of setae like worker; pronotum with 1 pair; mesoscutum with 8; axilla with 1; scutellum with 1 pair; first gastral tergite with number and arrangement similar to worker.

Type Material

Syntype worker, queen, larva: Costa Rica, La Caja (H. Schmidt) DEIC (examined).


  • Brown, W. L., Jr.; Kempf, W. W. 1960. A world revision of the ant tribe Basicerotini. Stud. Entomol. (n.s.) 3: 161-250.
  • Longino J. T. 2013. A review of the Central American and Caribbean species of the ant genus Eurhopalothrix Brown and Kempf, 1961 (Hymenoptera, Formicidae), with a key to New World species. Zootaxa. 3693:101-151. doi:10.11646/zootaxa.3693.2.1

References based on Global Ant Biodiversity Informatics

  • INBio Collection (via Gbif)
  • Longino J. T. 2013. A review of the Central American and Caribbean species of the ant genus Eurhopalothrix Brown and Kempf, 1961 (Hymenoptera, Formicidae), with a key to New World species. Zootaxa 3693(2): 101-151.
  • Longino J. T. 2013. Ants of Nicargua. Consulted on 18 Jan 2013.
  • 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.
  • Longino J. T., and R. K. Colwell. 2011. Density compensation, species composition, and richness of ants on a neotropical elevational gradient. Ecosphere 2(3): 16pp.
  • Longino J. et al. ADMAC project. Accessed on March 24th 2017 at