Hylomyrma plumosa

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Hylomyrma plumosa
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Pogonomyrmecini
Genus: Hylomyrma
Species: H. plumosa
Binomial name
Hylomyrma plumosa
Pierce, Branstetter & Longino, 2017

Hylomyrma plumosa inbiocri001239432 p 1 high.jpg

Hylomyrma plumosa inbiocri001239432 d 1 high.jpg

Specimen Label

This species occurs in wet forests at elevations between 50 and 300 m. Seventeen specimens were collected in the leaf-litter, which suggests that this species nests in fallen logs, rotten wood, between leaves, or inside natural cavities of the superficial soil layers. (Ulyssea & Brandao, 2021)


Pierce et al. (2017) - At least some of dorsal setae branched, usually trifid. Though the plumose setae and short gastral striation of Hylomyrma plumosa are distinctive, the species is otherwise extremely similar to Hylomyrma dentiloba and Hylomyrma versuta.

Ulyssea & Brandao (2021) - Mesosoma and petiole covered with thin striae (microsculpture) superimposed on irregular and thick striae (macrosculpture), interspaces between thinner striae indistinguishable; conspicuous and trifid setae.

Hylomyrma plumosa is identified based on the conspicuous and trifid setae (Fig. 80K). This species resembles Hylomyrma versuta, described by Kempf (1973) as “long hairs, pointed at tip, gently curved on petiole and postpetiole”. However, the types of H. versuta and additional examined material comprise specimens with unbranched and branched setae. The branched setae of H. versuta, mostly present on the petiole, postpetiole, and gaster, are composed of a variable number of short branches with similar size (Fig. 80F). These branched setae are not conspicuous as in Hylomyrma longiscapa, H. plumosa, and Hylomyrma transversa, being better observed in SEM images. Hylomyrma plumosa and H. versuta are locally sympatric (Figs. 85, 88), having been collected in the same sample (ALAS #03/WF/02/) near La Virgen (300 m), and in different samples (H. plumosa #AMI-1-W-006-01, and H. versuta #AMI-1-W-006-05) from the La Selva Biological Station (50 m); both locations in Heredia Province, Costa Rica. The two species have very similar body sculpture. The difference between them is very subtle: the propodeum is laterally covered by thin striae (microsculpture) with indistinguishable interspaces superimposed on irregular and thick striae (macrosculpture) in Hylomyrma plumosa, whereas H. versuta presents thin striae (microsculpture) with indistinguishable interspaces between irregular and thick striae (macrosculpture). Initially, we understood that H. plumosa and H. versuta belonged to a continuum of variation due to their body sculpture similarity, variable setae, and co-occurrence. But molecular data show H. plumosa as sister to the H. cf. dentiloba sp.2 (the true H. dentiloba)–H. versuta clade (Pierce et al. 2017). In this scenario, we have decided to maintain all three species as valid until additional evidence is gathered. Further investigative approaches using UCEs should include representatives of all the variation found in these taxa (or nominal species).

Keys including this Species


Latitudinal Distribution Pattern

Latitudinal Range: 10.43584175° to 9.66444°.

Tropical South

Distribution based on Regional Taxon Lists

Neotropical Region: Costa Rica (type locality).

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.




Images from AntWeb

Hylomyrma plumosa casent0638700 h 1 high.jpgHylomyrma plumosa casent0638700 p 1 high.jpgHylomyrma plumosa casent0638700 p 2 high.jpgHylomyrma plumosa casent0638700 d 1 high.jpgHylomyrma plumosa casent0638700 l 1 high.jpg
Holotype of Hylomyrma plumosaWorker. Specimen code casent0638700. Photographer Michele Esposito, uploaded by California Academy of Sciences. Owned by CAS, San Francisco, CA, USA.
Hylomyrma plumosa casent0636886 h 1 high.jpgHylomyrma plumosa casent0636886 p 1 high.jpgHylomyrma plumosa casent0636886 d 1 high.jpg
Worker. Specimen code casent0636886. Photographer M. Pierce, uploaded by University of Utah. Owned by University of Costa Rica.


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

  • plumosa. Hylomyrma plumosa Pierce, M.P., Branstetter, et al. 2017: 140, figs. 3, 5, 7 (w.) COSTA RICA.
    • Type-material: holotype worker, 13 paratype workers.
    • Type-locality: holotype Costa Rica: Limón, Hitoy-Cerere, 9.66480, -83.02346±10 m., 250 m., 10.vi.2015, Wa-E-02-2-38 (project ADMAC); paratypes with same data.
    • Type-depositories: CASC (holotype); MCZC, JTLC, UCDC, UCRS, USNM (paratypes).
    • Status as species: Ulysséa & Brandão, 2021: 89 (redescription).
    • Distribution: Costa Rica, Ecuador, Panama.

Type Material

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



(holotype worker): EL 0.211, EW 0.13, GSL 0.089, HFL 0.735, HL 0.799, HW 0.784, ML 1.042, OMD 0.109, PpL 0.253, PpW 0.3, PronW 0.573, SL 0.591, SPL 0.228, CI 98, GSI 9, OI 27, PpWI 119, SI 75, SPI 29. Measurements (range, n = 15): EL 0.202 - 0.235, EW 0.109 - 0.138, GSL 0.089 - 0.12, HFL 0.709 - 0.801, HL 0.793 - 0.871, HW 0.759 - 0.842, ML 0.991 - 1.137, OMD 0.095 - 0.12, PpL 0.227 - 0.285, PpW 0.293 - 0.331, PronW 0.55 - 0.618, SL 0.544 - 0.622, SPL 0.212 - 0.253, CI 93 - 99, GSI 8 - 11, OI 26 - 28, PpWI 114 - 133, SI 70 - 77, SPI 27 - 31.

Head subquadrate, occipital margin very slightly convex, occipital corners rounded. Clypeus bidentate, area between denticles mostly straight. Frontal lobes convex, ending anteriorly in a rounded angle, projecting over antennal insertions. Rugae on head running longitudinally and parallel, not intersecting; rugae interrupted occasionally by short gaps. Interrugal spaces microstriate, subopaque. Eye large, ending anteriorly in elongate tapering lobe. Scape tapered toward insertions and covered by abundant suberect non-branched hairs.

In profile view mesosoma convex, profile uninterrupted. Sides and dorsum of mesosoma reticulate rugose, interrugal spaces microstriate, subopaque. Propodeal spines relatively short, projecting posteriorly.

Peduncle of petiole present but not well developed. Sides and dorsum of petiole rugulose. Postpetiole subquadrate, covered on dorsum by longitudinal striae. Gaster mostly smooth and shining, striations on dorsum of tergum 1 short, but longer than Hylomyrma montana.

Body color reddish to reddish-brown, legs somewhat lighter, gaster darker brown. Dorsum of head, mesosoma, and gaster abundantly setose, at least some setae branched, bifid or more often trifid.


This species is named for the distinctive branched hairs that distinguish it from all other Hylomyrma.


References based on Global Ant Biodiversity Informatics

  • 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.