Species: Stenamma schmidti

Taxonomic History (provided by Barry Bolton, 2013)

Distribution:

From Branstetter (2013): Nicaragua to Ecuador.

From J. Longino (Ants of Costa Rica): Costa Rica: Cordillera de Tilaran, C. Volcanica Central, and C. de Talamanca, from 1000-2200m elevation.

Biology:

From Branstetter (2013): 

Stenamma schmidti, as defined here, is a rather variable species. It inhabits tropical wet forest environments from sea level to about 2400 m, becoming most abundant in cloud forest habitats above 800 m. At some cloud forest sites, S. schmidti can be one of the most common ant species occupying the leaf litter. Despite this fact, the species is very cryptic and finding nests is an uncommon event. Most collections of S. schmidti are from Winkler or Berlese samples of sifted leaf litter or epiphyte mats. Nest collections have been made, but these are very rare for the leaf-litter dwelling variants and only slightly more common for the arboreal forms. Nests are very small, with only tens of workers, and a single egg-laying queen. Workers, when encountered, are very slow moving and freeze upon disturbance. Additional natural history notes specific to particular morphological variants are described below.

From J. Longino (Ants of Costa Rica):
Natural History:

This species is a cloud forest specialist. Workers and queens occur in nearly every Winkler sample from montane habitats, in the 1000-2000m zone. Although very common in Winkler samples, I have very rarely found nests. I did once find a colony in leaf litter at the top of the upturned disk of roots and soil at the base of a fallen tree. The workers curled up and froze upon disturbance. The white brood pile gave them away, however.

Identification:

The worker of Stenamma schmidti can be identified by the following features:

• Note that this species is highly variable. See "comments section" below discussing morphological variants.
• Integument mostly dark brown, red-brown, or brown
• Small- to medium-sized species
• Petiolar node in profile usually broadly rounded and distinctly angled posteriad
• Postpetiole in profile subspherical
• Propodeal spines absent to tuberculate (PSL 0.06–0.13, PSI 0.8–1.5)
• Basal margin of mandible usually with a distinct basal notch and small accompanying tooth, but sometimes with only a small notch, or with basal margin sinuous 
• If basal margin of mandible with notch and tooth then: anterior clypeal margin forming 2–4 sharp to blunt teeth, with outer teeth more projecting; eye of moderate to large size (EL 0.10–0.18, REL 19–29), with 6–10 ommatidia at greatest diameter.
• If basal margin with small notch, but no tooth then: face completely sculptured, densely rugoreticulate; mesosoma mostly sculptured, punctate-rugulose; pilosity on first gastral tergite sparse, mostly stout and suberect, with only a few decumbent setae.
• If basal margin of mandible sinuous (without notch and tooth) then: anterior clypeal margin with a simple median emargination; propodeal spines absent, reduced to blunt angles where propodeal dorsum and declivity meet; eye large (EL 0.15–0.18, REL 22–27), with 8–11 ommatidia at greatest diameter; face usually completely sculptured, but sculpture never very dense, mostly carinulate- punctate; carinulae usually longitudinal, but some specimens with transverse carinulae on anterior half of head; pronotum either completely carinulate-punctate, lightly punctate, or completely smooth; carinulae when present usually transverse in orientation; some specimens noticeably long and gracile, with scape, metafemur, and petiole relatively long (SI 107–121, 86–93; PL/HW 0.58–0.63); gastral pilosity mostly sparse and suberect, with only a few decumbent to appressed setae; erect setae often stout.

Similar species:  S. nanozoi, S. saenzae, S. sandinista.

Notes:

References:

Taxon Page Author History

On 2013-04-28 13:51:44 Michael Branstetter modified Identification
On 2013-04-28 13:51:22 Michael Branstetter modified Biology
On 2013-04-28 13:50:53 Michael Branstetter modified Identification
On 2013-04-28 13:36:52 Michael Branstetter modified Biology
On 2013-04-28 13:36:03 Michael Branstetter modified Biology
On 2013-04-28 13:33:36 Michael Branstetter modified Distribution
On 2013-04-28 13:33:09 Michael Branstetter modified Distribution

Specimen Data Summary

Found most commonly in these habitats: 461 times found in montane wet forest, 143 times found in cloud forest, 149 times found in mature wet forest, 96 times found in tropical wet forest, 32 times found in primary cloud forest, 53 times found in ridgetop cloud forest, 24 times found in tropical rainforest, 10 times found in wet forest, 7 times found in forest, 7 times found in CES (700.350 GIS), ...

Collected most commonly using these methods or in the following microhabitats: 348 times Mini Winkler, 367 times miniWinkler, 182 times Winkler, 87 times Berlese, 42 times fogging, 22 times search, 14 times maxiWinkler, 7 times Search & Berles, 4 times baiting, 3 times Malaise, 4 times flight intercept trap, ...

Elevations: collected from 50 - 2400 meters, 1194 meters average

15 Specimens Imaged | View All 1662 Specimens for this species

CASENT0039766

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CASENT0126220

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CASENT0600137

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CASENT0600256

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CASENT0605211

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CASENT0605896

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CASENT0622465

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INB0003210597

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INB0003659320

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INB0003659427

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INB0003662571

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INB0003665417

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INBIOCRI001280989

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INBIOCRI002281270

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INBIOCRI002281278

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