Neivamyrmex impudens (Mann 1922)

Male of this species is N. longiscapus Borgmeier 1953, which should be made a jr. syn.

Ecitoninae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker face view

worker lateral view


Mexico (Chiapas), Guatemala, Honduras (type locality), Costa Rica. Costa Rica: Atlantic lowlands.


Posterior face of propodeum straight, not concave, shorter than dorsal face; eye with distinct convex cornea; color light red brown; promesosomal dorsum relatively arched, not in same plane as dorsal face of propodeum; anteroventral petiolar margin with sharp recurved tooth.

Natural History

I know this species from multiple collections of nocturnal columns. One observation at La Selva Biological Station was a very fast, tight column running with brood. The exposed part of the column was 10-20m long. It emerged from a simple hole in ground under leaf litter, at which point there was a large pile of brood. Workers were transporting this brood 10-20m to a point between two buttresses, where they disappeared into a simple hole. A second observation at La Selva was also a rapid, dense column. It was crossing the trail to river station near the Sura at 2300hrs. The column was descending from as high as I could see in the vegetation on one side, crossing the trail, and ascending into the vegetation on the other side. The steady stream of workers never diminished during the half hour I watched. None of the workers appeared to be carrying anything substantial, although I occasionally saw one with a tiny white object, perhaps an egg or small larva. Some workers were uniformly reddish, but others were reddish with contrasting bright yellow abdomens.


This species is a nocturnal version of pilosus mexicanus. Males and workers have similar morphology.

Note of 15 January 2010: Borgmeier (1955) speculated that longiscapus, known only from males, might be the male of impudens. CO1 (DNA barcode) sequence data (courtesy Alex Smith and BOLD) confirm that impudens workers and longiscapus males from a site in Guatemala are the same. I now consider longiscapus a jr. syn. of impudens and have changed my specimen database accordingly.

Page author:

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

Date of this version: 15 January 2010.
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