Rogeria inermis

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Rogeria inermis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Solenopsidini
Genus: Rogeria
Species: R. inermis
Binomial name
Rogeria inermis
Mann, 1922

Rogeria inermis P casent0280813.jpg

Rogeria inermis D casent0280813.jpg

Specimen Label

Widespread in wet forests from sea level to 500m. Specimens examined for Kugler’s generic level revision were from elevations that ranged from 10m to 1250m. Some were collected in fruit bat guano; others, in Berlese samples from rain forest leaf litter.


Kugler (1994) - Most similar to but not quite like other species in the creightoni species group. WL 0.60-0.85mm. Clypeal apron medially emarginate. Eye oval, moderately large. Nuchal grooves weakly visible in lateral view. Propodeal spines short to absent. Propodeal spiracles rather large, prominent, face somewhat caudad, usually < 1/2 diameter from edge of infradental lamella. Promesonotal dorsum rugose to areolate-rugose; pronotal sides rugose, shiny. Scapes with erect hair. Head dorsum with erect hairs and shorter, decumbent pilosity. Hair on mesosoma and gaster Tl subdecumbent to erect; not two distinct kinds. Pilosity on gaster rather sparse. Extensor surfaces of tibiae with decumbent to suberect hairs.

Rogeria leptonana from Cerro Pico Blanco, Costa Rica and Nueva California, Panama have reduced or absent propodeal spines, but differ from inermis in: 1) generally smaller size (WL 0.57-0.66mm; only 1 of 49 inermis workers with WL < 0.67mm), 2) smaller eye (6-8 facets; OI 0.11-0.12), and 3) mesosoma and gaster T1 dorsa with 2 distinct types of pilosity. Rogeria belti, often collected with inermis, has longer propodeal spines and more areolate head and pronotal sculpture. See also Rogeria neilyensis.

Keys including this Species


Guatemala to Panama

Latitudinal Distribution Pattern

Latitudinal Range: 18.5859972° to 8.407045°.

Tropical South

Distribution based on Regional Taxon Lists

Neotropical Region: Belize, Costa Rica, Guatemala, Honduras (type locality), Mexico, Nicaragua, Panama.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.


Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.



The following is modified from Kugler (1994): Little is known about these cryptic ants. Collection records typically range from sea level to 1000m, but five species extend higher and two (Rogeria unguispina and Rogeria merenbergiana) can be found at 2000m. Rogeria are generally collected in moist forests (primary or secondary forests, coffee or cacao plantations), but at higher elevations can be found in pastures (Rogeria leptonana, Rogeria merenbergiana). Several species (Rogeria creightoni, Rogeria cuneola, Rogeria foreli) have been found in moist and dry climates. Rogeria foreli is the most unusual, with some members dwelling at over 1800m in the temperate mountains of southern Arizona.

Most species have only been collected as strays or by Berlese or Winkler sampling, from leaf litter and rotten wood, but occasionally among epiphytes and moss (Rogeria belti, creightoni, Rogeria exsulans). Nests of several species (belti, Rogeria blanda, merenbergiana) have been found under the loose bark of rotten logs. Nests of blanda and Rogeria tonduzi have been taken from the trunks of cacao trees. A nest of Rogeria leptonana was found at 1750m under a rock in a pasture.

Nests are rarely found. Males are known for only four species (belti, blanda, leptonana and Rogeria stigmatica) and queens associated through nest series for only nine species.


Queens have been collected have not been described. Males have not been collected.


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

  • inermis. Rogeria inermis Mann, 1922: 32, fig. 15 (w.) HONDURAS. Kugler, C. 1994: 63 (q.).

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

Kugler (1994) - Two specimens from the Osa Peninsula of Costa Rica differ from the other specimens in having noticeably longer propodeal spines and longitudinal, rather than transverse sculpture on the back of the head. These may be members of a sibling species, but spine length is quite variable in inermis (e.g. PSI 0.04-0.09 in one Berlese sample). Thus, I hesitate to name a new species until more specimens show consistent differences.



Kugler (1994) - TL 2.2-3.0, HL 0.55-0.71, HW 0.48-0.63, SL 0.38-0.50, EL 0.09-0.13 (15-28 facets), PW 0.34-0.47, WL 0.60-0.85, SpL 0.03(no spines)-0.10, PetL 0.25-0.37, PpetL 0.14-0.20mm, CI 0.82-0.91, OI 0.18-0.22, SI 0.73-0.88, PSI 0.04(no spines)-0.14. N=15

Kugler 1994 fig 40-43

Mandibles with 5 or 6 teeth, usually five decreasing in size basad then a large basal tooth. Palpal formula 3,2. Median clypeal apron weakly to strongly emarginate. Posterior outline of head convex. Metanotal groove weak to absent. Anterior edge of propodeum sometimes marked by a transverse ridge. Propodeal spines usually short and acute, but may also be quite long, blunt, or absent. Petiole with a distinct, rounded node; peduncle slender, venter with strong tooth, but little or no keel. Postpetiolar node highest in posterior half; shape in domal view subtrapezoidal as in Fig. 49. Anterior lip of postpetiolar sternum square, not protruding. Pygidium as in creightoni-group diagnosis.

Sting apparatus as in Fig. 42. Spiracular plates with incomplete medial connection; spiracle not enlarged. Anterodorsal corner of quadrate plate prominent, with medial and lateral lobes. Oblong plate anterior apodeme long, slender; ventral arm tall, with long, slender fulcral arm. Gonostylus with dorsoterminal and companion setae; no gap between these and other sensilla. Lancets strong, acute, with a single minute apical barb. Sting shaft slender, straight; apex strong, acute, with low dorsal flange. Valve chamber and sting bulb large, subequal in height and length. Sting base much lower than bulb height, with weak anterolateral processes. Furcula an inverted Y -shape. See Kugler (1978b) for a more complete description.

Microsculpture on head and mesosoma reduced to vague irregularities in otherwise smooth and shiny interrugal spaces. Middorsum of head longitudinally rugose with lateral spurs, grading to areolate-rugose on laterodorsa and sides. Sculpture below and behind the eye sometimes vestigial, leaving a shiny area. Posterior head in most specimens transversely arching rugose (with lateral spurs) to areolate-rugose, but longitudinally rugose in two workers from the Osa Peninsula of Costa Rica. Rugae on mesosoma are sharp, with broad interrugal spaces that are even smoother and shinier than on the head. Anterior pronotum with 1-3 transverse rugae; disc with longitudinal rugae; meso- and metanotum vermiculate-rugose or areolate-rugose. Pronotal sides, mesopleura, and metapleura predominantly rugose; intervals very shiny. Dorsal face of propodeum transversely rugose to areolate. Sides of petiolar node weakly rugose to rugose-areolate, producing an uneven, shiny surface; apex smooth. Postpetiolar node largely smooth and shining with only slight unevenness of surface on sides.

Color varies from a reddish-brown (almost black) body with yellowish brown appendages to a yellowish-brown body with darker gaster and brownish-yellow appendages.


Kugler (1994) - TL 2.9-3.0, HL 0.62-0.64, HW 0.55-0.57, SL 0.41-0.45, EL 0.15-0.16, PW 0.47-0.48, WL 0.81-0.84, SpL 0.09, PetL 0.32-0.36, PpetL 0.18-0.19rnrn, CI 0.89, SI 0.74-0.79, PSI 0.11. N=3

Mandibles with 6 teeth, or 5 teeth and 2 denticles. Parapsidal furrows not discernible. Sculpture on posterior head of Panamanian specimens transversely rugose-areolate; more longitudinally oriented in Costa Rican specimens. Pronotum transversely rugose-areolate. Mesonotal sculpture predominantly rugose, with some closed cells. Dorsal face of propodeum transversely rugose. Petiolar node with weak macrosculpture, postpetiole smooth.

Type Material

Kugler (1994) - Syntype workers, HONDURAS: Progreso, Lombardia (Mann) Museum of Comparative Zoology [3 of 5 syntypes examined].


  • Kugler, C. 1994. A revision of the ant genus Rogeria with description of the sting apparatus (Hymenoptera: Formicidae). J. Hym. Res. 3: 17-89 (page 63, queen described)
  • Mann, W. M. 1922. Ants from Honduras and Guatemala. Proc. U. S. Natl. Mus. 61: 1-54 (page 32, fig. 15 worker described)

References based on Global Ant Biodiversity Informatics

  • Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology
  • Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
  • INBio Collection (via Gbif)
  • Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
  • Kugler C. 1994. A revision of the ant genus Rogeria with description of the sting apparatus (Hymenoptera: Formicidae). Journal of Hymenoptera Research 3: 17-89.
  • Levings S. C. 1983. Seasonal, annual, and among-site variation in the ground ant community of a deciduous tropical forest: some causes of patchy species distributions. Ecological Monographs 53(4): 435-455.
  • 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., J. Coddington, and R. K. Colwell. 2002. The ant fauna of a tropical rain forest: estimating species richness three different ways. Ecology 83: 689-702.
  • 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
  • Mann W. M. 1922. Ants from Honduras and Guatemala. Proceedings of the United States National Museum 61: 1-54.
  • Philpott, S.M., P. Bichier, R. Rice, and R. Greenberg. 2007. Field testing ecological and economic benefits of coffee certification programs. Conservation Biology 21: 975-985.