Eciton dulcium crassinode

Identification
Jack Longino:

Minor worker: head and mesosoma dark red brown, metasoma contrasting orange brown; occipital tooth absent; petiolar teeth long, tapered, and sharp, not in the form of flanges; petiole with anterodorsal elevated flange; fourth abdominal tergite with abundant long pubescence beneath erect setae.

Major worker: face densely micropunctate, matte; long sickle-shaped mandibles simple, without tooth on inner margin; petiole lacking anterodorsal flange; other characters as in minor.

Distribution based on Regional Taxon Lists
Neotropical Region: Costa Rica, Panama.

Biology
Jack Longino: 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 labelling 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.

Nomenclature

 *  crassinode. Eciton dulcius subsp. crassinode Borgmeier, 1955: 209 (s.q.) PANAMA.