Formicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
Costa Rica: Cordillera de Tilaran, Meseta Central.
Minor worker: propodeum very narrow and elongate, in cross section tectiform (tent-like, like an inverted "V"), without a distinct angle separating lateral and dorsal faces; dorsal and posterior faces of propodeum meeting at a right angle; color yellow.
Major worker: head cylindrical, strongly phragmotic.
Similar species: curviscapus, claviscapus.
I know this species from two collections in Monteverde. Both nests were from the same small second growth tree, in dead branches. The tree was in the community area, at the edge of a moist forest patch and a pasture. It has also been collected by Diana Wheeler in the Cerros de Escazu outside of San Jose.
This is the southernmost extent of the lineage of "Colobopsis" ants in the New World. They are characterized by the strongly phragmotic head of the soldiers. The head is strongly cylindrical, and the anterior truncation is perfectly round and nearly perpendicular to the long axis of the head. One major worker can neatly plug the entrance to the nest, so that the circular entrance hole is completely sealed, and the flat surface of the truncation is flush with the surface of the branch or other nest substrate (some North American species nest in oak galls). Other species placed in the taxon Colobopsis occur in Mexico and the southeastern United States.
Colobopsis itself is possibly a monophyletic group, with the phragmotic head of the major being the main synapomorphy. There is debate on the rank of the taxon, with some placing it as a subgenus of Camponotus (the approach used here) and others arguing that it should be a separate genus. Elevating Colobopsis to genus would almost certainly make Camponotus paraphyletic. I have not seen any convincing evidence that Colobopsis is anything other than a specialized Camponotus. I see a character transition series from C. claviscapus to C. curviscapus to the Colobopsis species.
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.firstname.lastname@example.org
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