Myrmelachista lauropacifica Longino 2006

Formicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker face view

worker lateral view

queen face view

queen lateral view

Queen in images above is holotype.

Additional images:

Holotype queen, label (large). Male, face view (large); wings (large); abdomen, lateral view (large); genitalia (large).


Costa Rica. In Costa Rica it occurs in the southern Pacific lowlands.


Diagnosis: Worker with antenna 9-segmented, maxillary palpus 5-segmented, color yellow. Queen with orange head, eyes relatively large (OI 33-37), HW less than 0.8mm. Obligate inhabitant of understory Lauraceae.

Worker: Same as M. flavocotea.

Measurements: HL 0.468-0.596, HW 0.414-0.537, SL 0.223-0.285, EL 0.098-0.110, CI 87-95 (n=4).

Queen: Antenna 9-segmented; maxillary palpus 5 or 6-segmented; labrum short, bilobed, not covering mouthparts; dorsal surface of mandible with piligerous puncta, interspaces smooth or slightly roughened; face and clypeus smooth and shining; in full face view, with abundant long erect to suberect setae projecting from sides of head, setae on posterior margin shorter; 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 erect to subdecumbent setae, longer setae shorter than width of tibia; color light yellow orange with infuscated bands on gastral terga.

Measurements: HL 0.900-0.966, HW 0.738-0.787, SL 0.363-0.402, EL 0.261-0.276, OW 0.076-0.089, OD 0.133-0.155, CI 77-82, OI 33-37, OcI 8-9 (n=4).

Male: Antenna 10-segmented; maxillary palpus 6-segmented; pygostyles absent; basiparamere lobe short, weakly sclerotized, half the length of paramere or less, in one collection drawn out as thin, sharp point, in another reduced to short triangular tooth; paramere weakly sclerotized, parallel-sided with rounded apex; cuspis absent (at high magnification, barely visible as tiny remnant); digitus evenly curved downward, tapering to rounded point; apodeme of penial valve curving into dorsal margin at obtuse angle.

Natural History

This species occurs in mature wet forest in the southern Pacific lowlands. I have collected it in Corcovado National Park and Carara Biological Reserve. Colonies have been in live stems of Lauraceae, with a biology similar to M. flavocotea. I found nests in O. cf. atirrensis and O. nicaraguensis. In Carara, O. nicaraguensis was common along the Quebrada Bonita. Small plants in the forest understory all contained M. lauropacifica, while larger plants in more insolated areas along the stream edge contained Azteca cf. pittieri and Pseudomyrmex viduus.

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.

Date of this version: 20 March 2006.
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