Species: Stenamma felixi

Taxonomic History (provided by Barry Bolton, 2013)

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:

From Branstetter (2013): Mexico (Atlantic slope) to Ecuador.

From J. Longino (Ants of Costa Rica): Mexico, Honduras (type locality), Costa Rica, Colombia. Costa Rica: commmon in wet montane forest throughout country, decreasing in abundance at low elevation; low density element at La Selva Biological Station.

Biology:

From Branstetter (2013)

Stenamma felixi is one of the most widespread and common species of MAC Stenamma. It occurs from approximately 50–1600 m, but is most common above 500 m, and is always found in wet forest environments, ranging from lowland rainforest to cloud forest. Workers have been collected by sifting leaf litter, beating and sweeping vegetation, baiting, using pitfall and Malaise traps, and by general searching. Nests are generally quite large and have been found in rotting logs on the ground, in tree stumps, under bark of logs, and rarely in mud banks. A few lone foundresses have been found under rotting epiphyte clumps in old treefalls, and some workers have been collected from orchids at quarantine in the U.S. All colonies collected so far have been monogynous. Workers seem to be epigeic, solitary foragers, but nothing is known about dietary preference. A very common experience is to find lone, stray workers running across medium- to large-sized logs in forest.

From J. Longino (Ants of Costa Rica)

Natural History:

Stenamma felixi occurs in wet forest habitats from 50m elevation rainforest to 1600m elevation cloud forest. It is rare at low elevation and relatively common above 500m. Workers can be encountered in Winkler samples of sifted leaf litter, Malaise trap samples, and sweep net samples. They appear to be epigaeic foragers, and perhaps they forage on low vegetation, but I never encounter them more than a meter above the ground. The workers are relatively large and conspicuous, and I often collect diurnal foragers. I do not know what they eat; foragers are solitary and they generally do not come to baits.

I have found relatively populous nests in dead wood on the ground, in rotten stumps or under loose bark of soft rotten logs. Colonies appear to be monogynous. Although I usually find nests in dead wood, I have found scattered lone foundresses under rotting epiphyte mats in old treefalls.

In my collection records I have more nest collections of Stenamma felixi than collections from Winkler samples. This is in striking contrast to most other species of Stenamma, where nests are rarely collected or unknown and the species is mainly known from Winkler samples.

Identification:

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

• Integument mostly black to dark brown
• Medium- to large-sized species
• Anterior clypeal margin with a median emargination
• Basal margin of mandible straight to slightly sinuous, without a basal notch or depression
• Head and mesosoma usually densely sculptured, with sharp carinae, rugae, or rugoreticulae
• Eye relatively large (EL 0.16–0.20, REL 18–22), oval-shaped, with 8–11 ommatidia at greatest diameter
• Propodeal spines absent, propodeum forming shallow, blunt angles where propodeal dorsum and declivity converge (PSL 0.07–0.11, PSI 0.8–1.1)
• Setae on gastral tergites mostly sparse, long, and suberect, only sometimes with a few short decumbent setae
• Frontal lobes of moderate width (FLD 0.22–0.26, FLI 25–29), not completely obscuring torular lobes in full face view
• Metafemur relatively long (MFI 75–88)

Similar species: Stenamma manni, S. schmidti.

Comments:

This species is rather distinctive with its large size, lack of propodeal spines, and dense sculpturing. It should not be easily confused with any other Middle American clade species.

Over its range, S. felixi shows considerable variation in the density and orientation of its sculpturing as well as in petiole shape. However, Branstetter (2013) only identifies one distinct variant (CASENT0622555) which is described in more detail. Specimens from Nicaragua and Costa Rica have very deep carinate sculpturing on the face and mesosoma. The facial carinae are usually longitudinal, but occasionally reticulate laterad. The pronotal dorsum has longitudinal carinae, but the side of the pronotum has arcuate carinae that wrap across the dorsum of the metanotum. The head in profile view has a very distinctive shape, in which the posterior margin of the head is very wide compared to the anterior margin, giving the head a somewhat triangular appearance. Lastly, the petiolar and postpetiolar nodes are noticeably smooth. Specimens from Colombia and Ecuador and from north of Nicaragua lose the carinate sculpture. All of the slight sculpture differences among popluations are treated as intraspecific variation as there is no evidence of sympatry among forms.

Notes:

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.

Taxon Page Author History

On 2013-04-30 08:13:57 Michael Branstetter modified Comments
On 2013-04-30 07:20:04 Michael Branstetter modified Comments
On 2013-04-30 07:18:34 Michael Branstetter modified Comments
On 2013-04-30 07:05:47 Michael Branstetter modified Comments
On 2013-04-30 07:04:39 Michael Branstetter modified Distribution
On 2013-04-30 07:04:08 Michael Branstetter modified Biology
On 2013-04-30 07:02:35 Michael Branstetter modified Overview
On 2013-04-28 08:34:36 Michael Branstetter modified References
On 2013-04-28 08:34:25 Michael Branstetter modified References
On 2013-04-28 08:34:06 Michael Branstetter modified Comments
On 2013-04-28 08:31:23 Michael Branstetter modified Distribution
On 2013-04-28 08:31:10 Michael Branstetter modified Biology
On 2013-04-28 08:30:48 Michael Branstetter modified Biology
On 2013-04-28 08:30:34 Michael Branstetter modified Biology
On 2013-04-28 08:29:44 Michael Branstetter modified Biology
On 2013-04-28 08:28:08 Michael Branstetter modified Identification
On 2013-04-28 08:27:57 Michael Branstetter modified Identification
On 2013-04-28 08:24:53 Michael Branstetter modified Distribution
On 2013-04-28 08:24:40 Michael Branstetter modified Distribution

Specimen Data Summary

Found most commonly in these habitats: 56 times found in montane wet forest, 41 times found in cloud forest, 9 times found in mesophyll forest, 5 times found in montane tropical rainforest, 12 times found in mature wet forest, 2 times found in mixed hardwood forest bordering stream, Liquidambar, oak, Heliconia, palms, 8 times found in montane rainforest, 5 times found in ridgetop cloud forest, 2 times found in mixed hardwood forest, 4 times found in rainforest, ...

Collected most commonly using these methods or in the following microhabitats: 1 times pitfall, 39 times search, 36 times MiniWinkler, 15 times Baiting, 19 times Berlese, 12 times MaxiWinkler, 18 times Mini Winkler, 14 times Winkler, 2 times quarantine, 8 times Beating, 8 times flight intercept trap, ...

Elevations: collected from 30 - 3050 meters, 1121 meters average

5 Specimens Imaged | View All 581 Specimens for this species

CASENT0126355

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CASENT0620969

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CASENT0622308

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CASENT0622311

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CASENT0622555

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