Neivamyrmex swainsonii (Shuckard 1840)

Ecitoninae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker face view

worker lateral view

worker face view

worker lateral view

Additional images: male, lateral view (small, large).


Southern USA to Argentina. Costa Rica: Northern Pacific lowlands, Atlantic lowlands, southern highlands.


Posterior face of propodeum straight, not concave, as long or longer than dorsal face; eye without distinct convex cornea, reduced to yellow speck below cuticle; apex of scape does not exceed eye level; anteroventral tooth of petiole large and triangular; face with sparse small puncta; basal tooth of mandible moderate to small; mesosoma of largest worker greater than 1.2mm; propodeal suture weakly impressed; dorsa of promesonotum and propodeum forming single flat surface; petiole in lateral view subquadrate, not pedunculate.

Compared to JTL-005: head relatively broader; anteroventral postpetiolar tooth relatively smaller; dorsal setae relatively longer.

Similar species: JTL-002, JTL-005, punctaticeps.

Natural History

I collected workers of this species under a rock on the ridge between Playa Naranjo and Playa Nancite in Santa Rosa National Park, an area of scrubby vegetation and grasses in a relatively xeric habitat. Ivette Perfecto collected workers in a coffee farm near Heredia. Curiously, males are known from La Selva Biological Station in the Atlantic lowlands and Wilson Botanical Garden in the southern mountains. During an 18-month program of sampling using blacklight traps at La Selva, as part of the ALAS project, males occurred in three different samples, in the months of March and May.


The workers of this species have traditionally been identified as fallax Borgmeier 1953. Bob Johnson told me that fallax is a junior synonym of swainsonii, a species previously known only from males. This is an unofficial synonymy at this point.

Page author:

John T. Longino, The Evergreen State College, Olympia WA 98505

Date of this version: 21 March 2008.
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