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Species: Stenamma llama   Branstetter, 2013 

Download Data

Taxonomic History (provided by Barry Bolton, 2020)

Stenamma llama Branstetter, 2013 PDF: 147, fig. 104-105 (w.) GUATEMALA. Neotropic. AntCat AntWiki


This species belongs to the Middle American clade of Stenamma (see Branstetter 2012). All conent on this page modified from Branstetter (2013) unless noted otherwise.

// Distribution


  Geographic regions (According to curated Geolocale/Taxon lists):
    Americas: Guatemala, Mexico
  Biogeographic regions (According to curated Bioregion/Taxon lists):

Distribution Notes:

Southern Mexico to Guatemala. No records from Belize.


Stenamma llama is a cloud forest specialist occurring from approximately 1100 m to 1600 m elevation. All specimens are known from sifted leaf litter collected from the forest floor, except for one, which was found at a cookie bait card. It is a rare species currently known from only one site in Oaxaca, Mexico, and one site in Guatemala. At the Guatemala site, out of 100 mini-Winkler and six maxi-Winkler samples, only six specimens were collected. The completely smooth and shiny integument of S. llama suggests that it nests in a relatively wet microhabitat.


Worker diagnosis. Integument black to brown-black; medium-sized species (see HL, ML, PrW below); anterior margin of clypeus with shallow median emargination; basal margin of mandible straight, without notch or substantial depression; head and mesosoma mostly smooth and shining; mesosoma compact, with promesonotum distinctly bulging; petiolar node robust, tall, and distinctly angled posteriad; propodeal spines forming short broad triangles (PSL 0.09–0.14, PSI 1.7-2.5); setae on gastral tergites sparse, long, and suberect; eye of moderate size (EL 0.11–0.15, REL 19-23), ovalshaped, with 6–8 ommatidia at greatest diameter; frontal lobes narrow, not obscuring torular lobe in full-face view (FLD 0.14-0.18, FLI 25-28).

Similar species: Stenamma lobinodus, S. tiburon.

     Worker description. (8 measured) HL 0.59–0.72 (0.70), HW 0.56–0.69 (0.64), FLD 0.14–0.18 (0.17), PCW 0.05–0.07 (0.06), SL 0.46–0.56 (0.55), EL 0.11–0.15 (0.14), ACL 0.45–0.53 (0.52), ML 0.76–0.99 (0.90), PrW 0.41–0.55 (0.50), PSL 0.09–0.14 (0.12), SDL 0.05–0.08 (0.07), PL 0.31–0.41 (0.38), PH 0.23–0.31 (0.31), PW 0.14–0.20 (0.19), PPL 0.17–0.21 (0.21), PPW 0.18–0.26 (0.23), MFL 0.52– 0.65 (0.63), MTL 0.39–0.50 (0.48), CI 92–96 (92), SI 80–85 (85), REL 19–23 (21), FLI 25–28 (27), PSI 1.7–2.5 (1.8), MFI 101–113 (101), ACI1 65–70 (68), ACI2 91–98 (95).
     Medium-sized species; general body color black to red- or brown-black, with mandibles and appendages lighter, usually dark brown to yellow-brown; setae light brown; mandible with 6 teeth, consisting of 3 distinct apical teeth, a basal tooth, and 2 inner teeth, which are often worn and indistinct; basal margin of mandible relatively straight, without any notch or significant depression; dorsal surface of mandible mostly smooth and shining, with scattered piligerous punctae and a few short basal striae; median lobe of clypeus with pair of very faint vestigial carinulae that diverge toward anterior margin, apex with a short transverse carinula, remainder of clypeus mostly smooth and shiny; posterior extension of clypeus between frontal lobes moderately broad (PCW 0.05-0.07), with subparallel to slightly diverging sides; frontal lobes narrow, not obscuring torular lobes in full-face view; head roughly oval-shaped (CI 92-96), but appearing somewhat tear drop-shaped because of the angled anterior margin of the clypeus and position of eyes; posterior margin of the head flat, never distinctly depressed medially; eye of moderate size (EL 0.11–0.15, REL 19-23), oval-shaped, with 6–8 ommatidia at greatest diameter; face almost completely smooth and shining, with scattered piligerous punctae and a few longitudinal carinulae on gena; scape short (SI 80-85), not reaching posterior margin of head when laid back; scape mostly smooth and shining, with scattered piligerous punctae, and sometimes a few fine striae; flagellum with a distinct 4-segmented antennal club; mesosoma usually mostly smooth and shiny, with some longitudinal carinae in metanotal groove, and a few scattered rugulae on propodeum, but some specimens with more developed sculpture on mesonotum, mesopleuron, and propodeum, consisting of faint carinulae and punctae; promesonotum domed and distinctly bulging upwards above head and propodeum; promesonotal suture usually completely effaced dorsally, but in a few specimens pronotum appears separated from mesonotum; metanotal groove distinct and of moderate depth; propodeal spines short, forming broad triangles (PSL 0.09–0.14, PSI 1.7-2.5); petiole of moderate length (PL/HW 0.52–0.62), node in profile robust and very tall (PH/PL 0.66–0.80), with anterior face longer and more sloping than posterior face, dorsum of node distinctly angled posteriad, and almost reaching a sharp apex; postpetiole in profile subcircular to oval-shaped, somewhat globular, always smaller than petiolar node (PPH/PH 0.70–0.84), dorsum usually with a somewhat distinct longitudinal median lobe; petiole and postpetiole mostly punctate, sometimes with faint rugulae, anterior faces of nodes smooth and shiny; gaster smooth and shiny except scattered piligerous punctae; most of body with moderately long, erect to subdecumbent setae; scapes with subdecumbent to decumbent setae; setae on legs mostly decumbent to appressed, with some suberect setae on femoral venters and coxae.
     Queen. Unknown.
     Male. Unknown.


With its mostly smooth sculpture and bulging promesonotum, S. llama is a very recognizable species. These characters, along with those given above, should make it easy to separate from all other Stenamma species.

Stenamma llama, along with S. lobinodus and S. tiburon, belongs to the lobinodus species group. Diagnostic features of the group are discussed on AntWeb and in Branstetter (2013) under S. lobinodus.

The specific epithet llama is used to honor the Leaf Litter Arthropods of MesoAmerica (LLAMA) project, which is responsible for collecting this species.

Taxonomic Notes:

Type material. Holotype worker. GUATEMALA: Zacapa, 2km SE La Unión, 14.95284N 89.27655W ±60m, 1450m, 14 May 2009 (LLAMA, collection Ba-B- 03-4-04-13) [USNM, specimen CASENT0605236]. Paratypes: same data as holotype but 14.94654°N, 89.27600°W ±6m, 1550m, 12 May 2009 (LLAMA, Wa-B- 03-1-01) [1w, CAS, CASENT0604931]; 14.94711°N, 89.27677°W ±50m, 1550m, 12 May 2009 (LLAMA, Wa-B-03-1-36) [1w, MGBPC, CASENT0604952]; 14.95436°N, 89.27690°W ±50m, 1430m, 12 May 2009 (LLAMA, Wa-B-03-2-10) [1w, MCZ, CASENT0604975], [1w, UCD, CASENT0606186], [1w, UNAM, CASENT0604974]; 14.95369°N, 89.27614°W ±50m, 1430m, 12 May 2009 (LLA- MA, Wa-B-03-2-32) [1w, UVGC, CASENT0604982].


Branstetter, M. G. 2012. Origin and diversification of the cryptic ant genus Stenamma Westwood (Hymenoptera: Formicidae), inferred from multilocus molecular data, biogeography and natural history. Systematic Entomology 37:478-496. 10.1111/j.1365-3113.2012.00624.x.

Branstetter, M. G. 2013. Revision of the Middle American clade of the ant genus Stenamma Westwood (Hymenoptera, Formicidae, Myrmicinae). ZooKeys 295:1-277. doi: 10.3897/zookeys.295.4905.

Specimen Habitat Summary

Found most commonly in these habitats: 5 times found in cloud forest, 2 times found in disturbed mesophyll forest, 2 times found in montane wet forest, 1 times found in tropical wet forest.

Found most commonly in these microhabitats: 9 times ex sifted leaf litter, 1 times at bait.

Collected most commonly using these methods: 6 times MiniWinkler, 3 times maxiWinkler, 1 times Baiting.

Elevations: collected from 1120 - 1550 meters, 1334 meters average

Collect Date Range: collected between 2009-05-12 and 2016-06-03

Type specimens: Paratype Stenamma llama: casent0604931, casent0604952, casent0604974, casent0604975, casent0604982

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