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Species: Stenamma brujita   Branstetter, 2013 

Classification:
Download Data

Taxonomic History (provided by Barry Bolton, 2020)

Stenamma brujita Branstetter, 2013 PDF: 56, figs. 54-57 (w.q.) GUATEMALA. Neotropic. AntCat AntWiki HOL

Overview:

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

Distribution:

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

Distribution Notes:

Mexico (Atlantic Slope) to Honduras.

Biology:

Stenamma brujita is known only from Winkler and Berlese samples of leaf litter collected from the floor of wet forest habitats (e.g. lowland rainforest, mon- tane wet forest, cloud forest, pine cloud forest, oak-pine forest). The species has a broad elevational range, occurring from 200–1800 m, but it is most common at mid elevations (1000–1500 m).

Identification:

Worker diagnosis. Integument mostly black, red-black, or brown; medium to large-sized species (see HL, ML, PrW below); head and mesosoma foveate to coarse rugoreticulate; eye relatively small (EL 0.09–0.13, REL 10–14), circular, and slightly bulging, with 5–7 ommatidia at greatest diameter; pilosity on gastral dorsum long, dense and mostly suberect; propodeal spines tuberculate to long and robust, usually of moderate length (PSL 0.15–0.37, PSI 1.3–2.9); anterior clypeal margin forming a single shallow to deep median emargination, or rarely, 4 blunt teeth; basal margin of mandible straight to sinuous, sometimes with a broad basal depression, but without a distinct notch or tooth; 4-segmented antennal club indistinct.

Similar species: Stenamma zelum.

     Worker description. (21 measured) HL 0.90–1.20 (1.05), HW 0.77–1.15 (1.00), FLD 0.21–0.32 (0.29), PCW 0.04–0.07 (0.06), SL 0.75–1.01 (0.93), EL 0.09–0.13 (0.12), ACL 0.63–0.78 (0.72), ML 1.15–1.62 (1.45), PrW 0.52–0.78 (0.70), PSL 0.15–0.37, SDL 0.08–0.16, PL 0.45–0.64 (0.56), PH 0.21–0.35 (0.27), PW 0.15– 0.24 (0.21), PPL 0.21–0.31 (0.26), PPH 0.18–0.28 (0.24), PPW 0.20–0.30 (0.27), MFL 0.81–1.25 (1.10), MTL 0.66–0.95 (0.88), CI 85–96 (96), SI 85–99 (88), REL 10–14 (12), FLI 25–31 (29), PSI 1.3–2.9 (2.3), MFI 86–105 (91), ACI1 62–65 (64), ACI2 78–89 (82).
     Medium to large-sized species; general body color usually red-black (type population) to black, with patches of brown, but some populations more uniformly brown; mandibles and appendages always lighter than body, brown to orange-brown; setae golden brown; mandible with 4–8 teeth (usually 7), consisting of 3–4 distinct apical teeth, a basal tooth, and a variable number of inner teeth, which are often worn and indistinct; basal tooth usually of moderate size (type population), but sometimes more robust and projecting; basal margin of mandible straight to slightly sinuous, sometimes with a shallow, broad basal depression, but without a distinct notch or tooth; mandible mostly smooth and shining, with scattered piligerous punctae and a few lateral striae; median lobe of clypeus usually slightly produced and clearly visible in full-face view (type population), but sometimes becoming obliquely flattened and angled more dorsoventrally, making it less visible; anterior clypeal margin varying from having a shallow to deep median emargination (type population), to forming 4 distinct blunt teeth; median lobe usually with a pair of faint longitudinal carinulae that diverge toward anterior margin, apex of lobe with a faint to strong transverse carinula; posterior extension of clypeus between frontal lobes of relatively moderate width (PCW 0.04–0.07), with sides subparallel to hour-glass-shaped; frontal lobes average to slightly expanded outward (FLD 0.21–0.32, FLI 25–31), with underlying torular lobes always visible in full-face view; head in full-face view roughly oval shaped to subcircular (CI 85–97), with posterior margin slightly to distinctly depressed medi- ally; eyes relatively small (EL 0.09–0.13, REL 10–14), circular, and somewhat bulging, with 5–7 ommatidia at greatest diameter; head foveate to coarsely rugoreticulate, shiny, often with a few short costae extending back from frontal lobes, interstices with piligerous punctae; scape relatively short, not reaching posterior margin of head when laid back (SI 85–99); scape shiny, usually with only scattered piligerous punctae (type population), but sometimes more robust, with punctae deeper and broader, becoming foveolae; flagellum with indistinct 4-segmented antennal club; mesosoma robust, foveate to coarsely rugoreticulate, with foveae most prominent on promesonotal dorsum; propodeal spines varying from short tubercles to long robust spines (PSL 0.15–0.37, PSI 1.3–2.9), which are usually spiniform and project dorsoposteriorly (type population), but sometimes form robust vertical pointing triangles; promesonotum in profile varying from being domed and nearly symmetrical (type population), to domed and asymmetrical, with apex occurring anterior of midpoint, to high-domed and asymmetrical; humeral angles rounded and indistinct, to becoming produced and angulate (type population), the latter occurring when the promesonotal side is scalloped slightly inward; metanotal grove present, but variable in depth and degree of distinctness; anterodorsal margin of propodeum in profile flat to distinctly raised into a welt (type population); propodeal declivity with a variable number of transverse carinae, often mostly smooth and shiny; petiole shape in profile usually appearing relatively long and somewhat gracile (PL/HW 0.53–0.63), with a small distinct node (PH/PL 0.45–0.55) (type population), but sometimes petiole is more robust and strongly wedge-shaped, without a clear distinction between the node and peduncle; postpetiole in profile usually low-domed, nearly symmetrical, and appearing as high or slightly smaller than petiolar node (type population), but sometimes postpetiole distinctly larger than petiolar node; postpetiole in dorsal view elongate, and reaching its widest point near posterior margin; waist sculpture variable, nodes usually mostly smooth and shiny, but sometimes more punctate and/or with longitudinal costae or rugulae, ventral surface punctate, dorsal surface of peduncle punctate and with a variable number of rugulae; gaster mostly smooth and shiny, with scattered piligerous punctae, and short furrows on anterior constriction where gaster inserts into postpetiole; most of body with rela- tively long standing pilosity; scape either with a single layer of mostly decumbent setae, or bilayered with a sparse layer of longer suberect setae over a denser decumbent layer (type population); gastral pilosity relatively long and somewhat dense, with most setae suberect to subdecumbent; setae on legs suberect to decumbent, with some popula- tions having predominately suberect setae (type population) and others mainly decum- bent setae, longer suberect setae always present on femoral venters and coxae.
     Queen description. (5 measured) HL 0.96–1.03 (1.03), HW 0.91–0.99 (0.99), FLD 0.26–0.29 (0.29), PCW 0.05–0.07 (0.06), SL 0.84–0.89 (0.89), EL 0.17–0.19 (0.17) ACL 0.68–0.72 (0.71), ML 1.47–1.57 (1.57), PrW 0.76–0.82 (0.82), PSL 0.18–0.28 (0.28), SDL 0.13–0.16 (0.13), PL 0.59–0.61 (0.60), PH 0.28–0.32 (0.31), PW 0.22–0.25 (0.24), PPL 0.27–0.33 (0.32), PPH 0.23–0.28 (0.28), PPW 0.25– 0.31 (0.29), MFL 1.01–1.06 (1.06), MTL 0.79–0.85 (0.85), CI 93–97 (97), SI 86–94 (90), REL 17–20 (17), FLI 28–31 (29), PSI 1.1–2.1 (2.1), MFI 87–95 (93), ACI1 63–64 (63), ACI2 80–85 (80). 
     Same as worker except for standard queen modifications and the following: Propodeal spines less variable (PSL 0.18–0.28, PSI 1.1–2.1), usually present, of moderate length, and thick at base (only Nahá population with spines tuberculate); setae on scape less variable, usually with a sparse layer of longer suberect setae and a layer of denser decumbent setae (only Nahá population with setae uniformly subdecumbent); wing venation as shown in specimen CASENT0621749.
     Male. Unknown.

Comments:

This species encompases the morphspecies codes mgb05, mgb06, mgb07, and mgb09.

The combination of large size, small eyes, and foveate sculpture make S. brujita (see CASENT0604945 for images of holotype) a very distinctive species, unlikely to be confused with any other Middle American clade Stenamma species. However, S. zelum, which is not closely related to S. brujita (Branstetter 2012), has converged on a similar phenotype and may cause problems with identification. Fortunately, these two species are geographically isolated from one another, with S. brujita reaching only as far south as northwestern Honduras, and S. zelum extending only as far north as northeastern Honduras. Using morphology, Stenamma brujita can be distinguished from S. zelum by its more rounded head (rectangular in S. zelum), longer propodeal spines (PSI 1.3–2.9 vs. 1.0–1.3), and lower FLI (27–31 vs. 31–34). In addition, the anterior clypeal margin forms four sharp teeth in S. zelum, with the outer teeth usually strongly projecting. In contrast, most populations of S. brujita have the anterior clypeal margin forming a single median emargination (all Honduras populations like this), and in those specimens that do have clypeal teeth, the teeth are all blunt.

Stenamma brujita is quite variable throughout its range and may comprise a complex of several species. Branstetter (2013) choose to identify a single species, because every population exhibits some amount of variation, none of the variants occur in sympatry, and some populations have intermediate phenotypes. Branstetter (2013) does however, identify three main variants that differ significantly from the holotype population.

Variant 1 (CASENT0604578; previously known as mgb07) includes all collections from Tamaulipas and Hidalgo, Mexico. It has the following features: body sculpture more rugoreticulate than foveate; propodeal spines long, straight and more slender; petiole with a distinct concavity below node.

Variant 2 (CASENT0604607; previously known as mgb06), the most distinctive variant, is known from a few collections taken on the wet Atlantic slope of the Sierra Juarez, between Oaxaca and Valle Nacional in Mexico. It has the following features: body very large; general body color very dark, mostly black; petiole wedge-shaped, usually without a distinct node; propodeal spines forming robust, blunt-tipped triangles, which point almost vertically.

Variant 3 (CASENT0603918; previously known as mgb05) occurs at several localities in Chiapas, México, mainly Nahá and Lago Metzabok. It is characterized by the following: general body color brown; promesonotum in profile high-domed, and asymmetrical; propodeal spines tuberculate; petiole in profile appearing more gracile with node reduced in size; anterior clypeal margin forming 4 blunt teeth.

Some additional populations in Chiapas, Mexico, and all of the populations in Guatemala and Honduras, are most similar to the holotype population (La Unión, Guatemala). However, there is considerable variation among populations and some have character states that are intermediate between the holotype form and the different variants just described. Specimens from higher elevations tend to be larger, darker and more robust. The specimens from Purulhá, Guatemala appear especially robust-looking, with very long, sinuous propodeal spines and coarser sculpturing. Interestingly, these specimens have the petiolar node more wedge-shaped, similar to variant 2. Key character states of the holotype population are indicated in the worker description of Branstetter (2013).

The specific epithet brujita is the spanish word meaning little witch. The name is used to reference the fact that ants are small, most are female, and that S. brujita has rough sculpturing, much like the skin on a stereotypical witch.

Taxonomic Notes:

Type material. Holotype worker. GUATEMALA, Zacapa: 2km SE La Unión, 14.94706°N, 89.27660°W ±50m, 1550m, 12 May 2009, cloud forest, ex sifted leaf litter (LLAMA, collection Wa-B-03-1-32) [USNM, specimen CASENT0604945]. Paratypes: same data as holotype but 14.94460°N, 89.27726°W ±57m, 1550m, 12 May 2009 (LLA- MA, Wm-B-03-1-04), [1w, CAS, CASENT0623248], [1w, EAPZ, CASENT0623249], [1w, ECOSCE, CASENT0623250], [1w, FMNH, CASENT0623251], [1w, ICN, CASENT0623252, [1w, INBio, CASENT0623253], [1w, JTLC, CASENT0623527], [1w, LACM, CASENT0623254], [2w, MGBPC, CASENT0623528, CASENT0623529], [1w, MCZ, CASENT0623255], [1w, MZSP, CASENT0623256, [1w, UCD, CASENT0623257], [1w, UNAM, CASENT0623258], [1dq, 1w, USNM, CASENT0606239, CASENT0606656], [1w, UVGC, CASENT0623259].

References:

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: 58 times found in mesophyll forest, 39 times found in cloud forest, 20 times found in montane wet forest, 8 times found in mesophil forest, 6 times found in lowland rainforest, 1 times found in pine cloud forest, 1 times found in mesophyl forest, 1 times found in Quercus forest, 2 times found in rainforest, 1 times found in tropical evergreen forest, ...

Found most commonly in these microhabitats: 136 times ex sifted leaf litter, 4 times forest litter, 3 times ex sifted litter, 2 times sifted litter (leaf mold, rotten wood), 2 times leaf litter, 1 times at bait, 1 times ex sifted log and leaf litter.

Collected most commonly using these methods: 103 times MiniWinkler, 24 times MaxiWinkler, 13 times Berlese, 7 times Winkler, 1 times Night MiniWinkler, 1 times Baiting, 1 times Hojarasca berlese.

Elevations: collected from 200 - 1790 meters, 1306 meters average

Collect Date Range: collected between 1971-05-19 and 2019-06-13

Type specimens: Holotype Stenamma brujita: casent0604945; Paratype Stenamma brujita: casent0606239, casent0606656



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