Myrmelachista osa

This species is known from mature wet forest. I collected it from three different Ocotea nicaraguensis trees, and it appears to have a biology similar to Myrmelachista flavocotea and others. (Longino 2006)

Identification
Longino (2006) - Worker with antenna 9-segmented, maxillary palpus 5-segmented, color yellow. Queen black; mandible punctatorugose; face smooth and shining; sides of head with short appressed to suberect pubescence, no longer erect setae; maxillary palpus 6-segmented; CI 79–84.

Distribution
Known from Rancho Quemado on the Osa Peninsula.

Distribution based on Regional Taxon Lists
Neotropical Region: Costa Rica.

Castes
Males have yet to be collected.

Nomenclature

 *  osa. Myrmelachista osa Longino, 2006a: 42, figs. 1, 4, 7, 8, 9 (w.q.) COSTA RICA.

Worker
HL 0.518–0.521, HW 0.479–0.511, SL 0.256–0.265, EL 0.097–0.105, CI 92–98 (n=3).

Same as Myrmelachista flavocotea but with tendency to develop faint infuscated bands on gastral tergites.

Queen
HL 1.181–1.226, HW 0.971–0.997, SL 0.491–0.507, EL 0.283–0.303, OW 0.062–0.081, OD 0.173–0.185, CI 79–84, OI 28–31, OcI 5–7 (n=3).

Antenna 9-segmented; maxillary palpus 6-segmented; labrum short, bilobed, not covering mouthparts; dorsal surface of mandible punctatorugose; face and clypeus largely smooth, variably roughened anteriorly; in full face view, with abundant short suberect setae on rear and side margins of head, longer setae on posterolateral vertex; 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 short subdecumbent setae, longer setae shorter than width of tibia; color solid black.

Type Material
Holotype alate queen: Costa Rica, Prov. Puntarenas, Rancho Quemado, Osa Peninsula, 8°42’N, 83°33’W, 200m, 15 Dec 1990 (J. Longino#2752), specimen code JTLC000006231.

Paratypes: workers and queens, from same nest as holotype, specimen codes JTLC000006232-JTLC000006236, distributed to, , , ,.

Etymology
The name refers to the Osa Peninsula, which is the type locality.