Suggested synonym:
= Pheidole glyphoderma Wilson 2003
Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Identification
Minor worker: head length 0.62mm, head width 0.58mm, scape length 0.58mm, Webers length 0.82mm (n=1). Head rounded to somewhat flattened behind; promesonotum evenly arched, mesonotal suture absent; propodeal spines short, sharp, upturned; sculpture on face, pronotum, and katepisternum varying from largely smooth and shining to densely punctatorugose; propodeum punctatorugose; gaster smooth and shining; dorsal pilosity abundant, long, flexuous; color dark red brown.
Major worker: head length 1.56mm, head width 1.34mm, scape length 0.62mm (n=1). Face punctatorugose beneath sweep of scapes; medial area between frontal carinae with parallel transverse rugae; vertex lobes smooth and shining; medial clypeus smooth, mat, in same plane with broad, flattened surfaces of mandibles (serving phragmotic function?); bases of frontal carinae elevated, tooth-like; hypostomal margin with no medial tooth, pair of teeth located less than one third distance to recessed teeth flanking mandibles; dorsal pilosity abundant; head with abundant suberect setae projecting from sides of head in face view.
Range
Costa Rica: Atlantic slope; La Selva to 1000m elevation in Braulio Carrillo; Penas Blancas Valley; Monteverde; Volcan Arenal.
Natural History
This species is found in or near primary forest. Workers recruit to baits, and may have seed caches in their nests. It nests in dead wood, dead branches, and live stems. Nests occur from ground level to the canopy.
Seven nests were observed in dead wood near ground level.
One nest was observed in a dead log, 10-20cm dia, suspended horizontally about 1m high. The log was largely solid but waterlogged throughout. The outer layers were wet and slimy with many worms. The Pheidole colony was in small chambers in a soft rotten area, about 1cm below the upper surface. The soft area was thoroughly excavated, and no more of the nest was found, so this collection probably contained most or all of the colony.
Nests may occur in live stems. Two nests were observed in internodes of Cecropia insignis saplings. In one case the colony was polydomous. Two nests were observed in live stems of Myriocarpa along streams. A nest was observed in a live branch (identity unknown) in a fresh treefall. The nest was in a discrete hollowed-out area; the stem was solid elsewhere. There were no Homoptera on the walls of the nest. There was a seed cache in the nest chamber.
Comments
Wilson (2003) identified a Monteverde collection as a new species, glyphoderma. We interpret this collection as within the range of variation of arietans. It is heavily sculptured, but appears to be at the end of a continuum from heavily sculptured forms to smooth and shiny forms.
Literature Cited
Wilson, E. O. 2003. Pheidole in the New World: A Dominant, Hyperdiverse Ant Genus. Harvard University Press, Cambridge, Mass
Page authors:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
Stefan Cover, Museum of Comparative Zoology, Harvard University, Cambridge MA 02138 USA. scover@oeb.harvard.edu
Last modified: 2 September 2003.
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