Formicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Queen in images above is holotype.
Additional images:
Holotype queen, lateral view with wings (large); label (large). Worker, maxillary and labial palpi (large). Male, face view (large); wings (large); abdomen, lateral view (large); genitalia (large).
Range
Costa Rica. In Costa Rica it occurs above 500m elevation in wet forest habitats of the Cordillera Volc‡nica Central, Cordillera de Tilar‡n, and Cordillera de Guanacaste.
Identification
Diagnosis: Worker with antenna 9-segmented, maxillary palpus 5-segmented, color yellow. Queen black; mandible punctatorugose; HW greater than 1.1mm; head relatively broad (CI 88-93); eyes relatively small (OI 23-27); much of face slightly roughened, dull, not strongly shining.
Worker: Similar to flavocotea. Compared to flavocotea, there is a tendency for the pilosity on the side and ventral surface of head to be shorter, the pilosity on the hind tibia to be more fully appressed, and the gastral terga to develop faintly infuscated bands, but these differences are difficult to quantify.
Measurements: HL 0.560-0.683, HW 0.520-0.660, SL 0.274-0.345, EL 0.105-0.121, CI 93-101 (n=5).
Queen: Antenna 9-segmented; maxillary palpus 6-segmented; labrum short, bilobed, not covering mouthparts; dorsal surface of mandible punctatorugose; face and clypeus roughened, becoming somewhat smoother posteriorly; clypeus often coarsely rugose; in full face view, with short erect to appressed setae on rear and side margins of head; ventral surface of head with abundant short erect setae; scapes with abundant erect to suberect setae, longer setae subequal to width of scape; outer surface of hind tibia with abundant setae, suberect to fully appressed, longer setae shorter than width of tibia; color solid black.
Measurements: HL 1.259-1.362, HW 1.135-1.223, SL 0.532-0.575, EL 0.283-0.309, OW 0.063-0.096, OD 0.227-0.267, CI 88-93, OI 23-27, OcI 5-7 (n=9).
Male: Similar to M. flavocotea. Differing in generally heavier sclerotization, darker color, and smaller ocelli. Width of median ocellus usually less than distance between median and lateral ocellus; distance between lateral ocelli less than distance from lateral ocellus to compound eye.
Natural History
This species occurs in mature wet forest habitats from 500-1100m elevation, where it nests in live stems of understory Lauraceae and Meliaceae. It has a biology similar to M. flavocotea but is more generalized in its host use. At Refugio Eladio in the Pe–as Blancas Valley it occurs in Ocotea dendrodaphne, O. atirrensis, O. tenera, and the undescribed species of Guarea that is the host for M. flavoguarea. Cerro Pedregal, across from Estaci—n Cacao in the Guanacaste Conservation Area, has a patch of understory O. tenera near the peak that is dominated by M. nigrocotea. Colonies can be monogynous or polygynous with 2-4 dealate queens. Stems often contain Pseudococcidae. Alate queens have been collected in Project ALAS Malaise traps on the Barva transect.
Literature Cited
Longino, J. T. (2006). A Taxonomic review of the genus Myrmelachista (Hymenoptera: Formicidae) in Costa Rica. Zootaxa 1141:1-54.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
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