Myrmelachista osa

AntWiki: The Ants --- Online
Myrmelachista osa
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Myrmelachistini
Genus: Myrmelachista
Species: M. osa
Binomial name
Myrmelachista osa
Longino, 2006

Myrmelachista osa jtlc000002698 p 1 high.jpg

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)


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.

Keys including this Species


Known from Rancho Quemado on the Osa Peninsula.

Latitudinal Distribution Pattern

Latitudinal Range: 8.7° to 8.7°.

Tropical South

Distribution based on Regional Taxon Lists

Neotropical Region: Costa Rica (type locality).

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.



Males have yet to be collected.


Images from AntWeb

Myrmelachista osa jtlc000006231 h 1 high.jpgMyrmelachista osa jtlc000006231 p 1 high.jpgMyrmelachista osa jtlc000006231 p 2 high.jpgMyrmelachista osa jtlc000006231 l 1 high.jpg
Holotype queen osaQueen (alate/dealate). Specimen code jtlc000006231. Photographer J. Longino, uploaded by University of Utah. Owned by INBC.


The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

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

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.



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.


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) Instituto Nacional de Biodiversidad, specimen code JTLC000006231.

Paratypes: workers and queens, from same nest as holotype, specimen codes JTLC000006232-JTLC000006236, distributed to Museum of Comparative Zoology, National Museum of Natural History, University of California, Davis, Los Angeles County Museum of Natural History, The Natural History Museum.


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