Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Identification
Mandibles with 5 distinct teeth, apical tooth largest, proximal tooth considerably smaller, remaining three teeth the smallest and subequal in size; mandibles shining, with large piligerous punctures; occipital carina visible in face view; promesonotal suture visible as a broad shallow depression; anteriomedial margin of mesonotum raised as a small triangular boss; propodeal suture not deeply impressed; propodeum with distinct dorsal and posterior faces, dorsal face with median longitudinal depression, posterodorsal margins vary from being strongly developed tubercles to mere bosses; ventral margin of postpetiole flat, sloping anteriorly, anterior margin often terminating in long, needle-like spine (figure: reduced, original) (variably developed; also easily broken off, and thus missing from some specimens); color orange to red brown, gaster darker than rest of body; HW 1.59; HL 1.82, SL 2.14; WL 2.62 (n=1).
Material I have examined from Costa Rica varies geographically in degree of development of propodeal tubercles (figure of propodeums, oblique view from top looking rearward), and color. A specimen from Limon province is strongly tuberculate, and red brown. Specimens from the San Vito area vary from strongly to weakly tuberculate, and are orange brown. Specimens from the Osa Peninsula are not at all tuberculate, and are red brown with strongly contrasting darker gaster.
Range
Colombia, Panama, Costa Rica. Costa Rica: scattered records from wet forest sites throughout the country.
Natural History
Specimens from Colombia bear labels "Cacao - associated with membracids Horiola picta (Coquebert)," and "arboles de cacao" (reported in Brandao 1990).
These large, conspicuous ants do not appear to be common in Costa Rica. I collected foreli several times in the San Vito area, and several times in Corcovado National Park. At San Vito, I encountered them as workers on the ground, during nocturnal collecting. In Corcovado, I encountered them in the hilly interior parts of the park, and not around Sirena on the coast. Workers occurred on the ground or on low vegetation. I once observed 15 workers together on one Costus inflorescence.
Literature Cited
Brandao, C. R. F. 1990. Systematic revision of the Neotropical ant genus Megalomyrmex Forel (Hymenoptera: Formicidae: Myrmicinae), with the description of thirteen new species. Arquivos de Zoologia (Sao Paulo) 31:411-481.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
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