Neivamyrmex JTL-005 Longino ms

Ecitoninae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker face view

worker lateral view

Note that the figured specimen is missing two terminal antennal segments on one side and four on the other, the condition in which the specimen was collected.

Additional images: worker, dorsal view (click here).


Costa Rica (Atlantic lowlands).


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 swainsonii: head relatively narrower; anteroventral postpetiolar tooth relatively larger; dorsal setae relatively shorter.

Similar species: JTL-002, swainsonii, punctaticeps.

Natural History

The single known worker of this species was collected in lowland rainforest, in Braulio Carrillo National Park between La Selva Biological Station and Magsasay. It was collected as part of the TEAM project, in a Winkler sample.


Karol Mora, TEAM project technician, discovered this ant. Among the thousands of ants in hundreds of species that she was processing and identifying, she isolated this single diminutive worker as something she had not seen before. Sadly, the Conservation International ant sampling has come to an end, so Karol won't be able to continue making discoveries like this one.

I first identified this diminutive worker as Asphinctanilloides, and sent it off to Phil Ward to be sequenced. The sequencing placed it in with Neivamyrmex, and when Phil took a closer look at the specimen he confirmed that it was a Neivamyrmex. It has a fused promesonotum, something I can see even in the images. Ah well. I was blinded by the wish for novelty, fame, and fortune. The sequencing clustered it with N. nigrescens, and Phil suggested it was possibly allied to N. pauxillus.

The single known worker of this species has the habitus of a tiny subterranean ant. If this is a typical worker size for the species (and not a tiny worker of a polymorphic species with larger workers), perhaps it belongs to one of the Barva species known from very small males: N. digitistipus, N. nr. digitistipus, JTL-003, or JTL-004.

Page author:

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

Date of this version: 21 March 2008.
Previous versions of this page: 6 November 2007
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