Species: Argentina, southern Brazil, Panama, Costa Rica. Subspecies: Panama (type locality), Costa Rica. Costa Rica: Atlantic and southern Pacific lowlands.
This appears to be one of the less common species of Eciton in Costa Rica. I know it from a couple of collections from the Osa Peninsula, and more recently a collection from La Selva Biological Station. This latter observation was a lesson in humility. With 15 years of ant survey work at La Selva, including multiple student projects in which teams of undergraduates searched the La Selva trails for army ants (including nocturnal surveys) I was sure there were only five species of Eciton at La Selva and E. d. crassinode did not occur there. Mike Kaspari emailed me a query, with images of specimens a student of his had collected at La Selva in 2003, and they looked like crassinode. I was surprised and wondered if it was possibly a labeling error. I had my doubts about Mike's record until a visit to La Selva in April 2006, when a nocturnal walk yielded a column of crassinode! Mike actually had two records from 2003, one at LOC1410 at 1043hrs, and one at LOC850 at 1700hrs. My record was at CES450 at 2100hrs.
The species as a whole appears to have an interesting geographic distribution, with dulcium s. str. in southern South America, and d. crassinode in Panama and Costa Rica.
In earlier literature this species appeared as Eciton dulcius.
Found most commonly in these habitats: 2 times found in lowland wet forest, 2 times found in wet forest, 1 times found in rainforest
Collected most commonly using these methods or in the following microhabitats: 5 times search, 1 times winkler
Elevations: collected from 50 - 300 meters, 146 meters average