Pheidole scalaris Wilson 2003

Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker face view

worker lateral view

major face view

major lateral view


Minor worker: head length 0.44mm, head width 0.40mm, scape length 0.34mm, Webers length 0.48mm (n=1). Head flattened and shallowly excavate behind; mesonotal suture absent; promesonotum evenly arched; propodeal spines short, spiniform; face and mesosoma uniformly foveolate except for shiny patch on side of pronotum; first gastral tergum smooth and shining; dorsal pilosity sparse, short, stiff; color orange.

Major worker: head length 0.81mm, head width 0.65mm, scape length 0.32mm (n=1). Face shiny, with subparallel longitudinal rugae between eyes and frontal carinae, subparallel transverse rugae on face between frontal carinae, reticulate rugae on posterior portion of face; antennal scrobes present in the form of shallow depressions beneath apices of scapes, surface of scrobe smooth and shiny; anterolateral margins of head flared, forming a narrow flange; hypostomal margin straight, with (La Selva) or without (Santa Rosa) rounded median tooth, with pair of pointed teeth one third to one half distance from midline to recessed teeth flanking mandible bases (Figure); dorsal pilosity abundant; head with abundant short setae projecting from sides of head in face view.

This species is close to and may prove to be conspecific with transversostriata Mayr 1887, a species from the Guianas.


Costa Rica (Atlantic and northern Pacific lowlands).

Natural History

Occurs in both seasonal dry forest and lowland rainforest; recruits to baits; does not occur in Winkler samples, which implies that it neither nests nor forages in forest leaf litter.

Selected Records

Santa Rosa National Park: seasonal dry forest; two-month old cleared right-of-way through old second growth vegetation (new powerline along "cafetal" road); at honey-crisco bait.

Santa Rosa National Park: evergreen forest patch surrounded by seasonal dry forest ("Bosque Humedo"); at tuna bait.

La Selva: recruiting to baits on forest floor.

Page authors:

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

Stefan Cover, Museum of Comparative Zoology, Harvard University, Cambridge MA 02138 USA.

Date of this version: 2 September 2003.
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