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Species: Pheidole olsoni   Wilson, 2003 

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Taxonomic History (provided by Barry Bolton, 2022)

Pheidole olsoni Wilson, 2003a: 478, figs. (s.) COSTA RICA. Neotropic. Primary type information: Primary type material: holotype major worker. Primary type locality: Costa Rica: Alajuela, Peñas Blancas Valley, 780 m. (D. Olson). Primary type depository: MCZC. AntCat AntWiki HOL

Taxonomic history

// Distribution


  Geographic regions (According to curated Geolocale/Taxon lists):
    Americas: Costa Rica, Guatemala, Honduras, Panama
  Biogeographic regions (According to curated Bioregion/Taxon lists):

Distribution Notes:

Costa Rica, Panama.


Note by Longino, 6 Nov 2013: DNA barcoding data caused a re-evaluation of P. olsoni. Previously, I had minor and major workers from Peñas Blancas (the type locality), major and minor workers from 1100m on the Barva transect, and minor workers only from lower on the Barva transect. The Peñas Blancas and Barva-1100m minors are subtly different from the minors lower on the Barva transect. The former are smaller, with shorter scapes; shorter and coarser dorsal pilosity; a faint lateral keel on promesonotum; and promesonotal profile less convex. DNA barcoding associates La Selva minors with morphospecies JTL219 from Cerro Musun in Nicaragua and La Mosquitia, Honduras. The major workers of JTL219 are radically different from P. olsoni majors.


The holotype is a major worker collected by David Olson at Refugio Eladio in the Penas Blancas Valley. We examined a series from Panama (Volcan Chiriqui, 18 Aug 1935, coll. L. Hare), and the major matches very closely the holotype. These specimens also match very closely a series of workers and one soldier collected at Las Cruces by L. and A. Alonso (in association with M. Kaspari). Multiple collections have been made by Project ALAS sampling along the Barva transect, from La Selva to the 1100m site.

Taxonomic Treatment (provided by Plazi)

Treatment Citation: Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA: Harvard University Press

Pheidole olsoniHNS new species

Types Mus. Comp. Zool. Harvard.

Etymology Named after the collector David Olson.

Diagnosis Known only from the major, easily distinguished by its very small size, elongated head, bicolorous body, protuberant frontal lobe in side view, small propodeal spine, cornulate postpetiole, and unusual pattern of the rugulae mesad to the eye, which travel downward (anteriorly) from the eye obliquely mesad to meet the circular carinulae of the antennal fossae. Similar to browniHNS, castaHNS, meraHNS, prolixaHNS, and protensaHNS, but easily separated by the above listed traits. measurements (mm) Holotype major: HW 0.54, HL 0.74, SL 0.30, EL 0.08, PW 0.30.

color Major: head, dorsum of alitrunk, petiolar node, and all of postpetiole medium brown; rest of body and all of appendages medium yellow.

range Known from the type locality and from El Volcan, Chiriqui, Panama, 1280 m (L. Hare).

biology The holotype was collected in rainforest at a tuna bait; the Chiriqui, Panama, specimens were found in a log. Males were present in the latter colony on 18 August.

figure Holotype, major. COSTA RICA: Refugio de Eladio, Penas Blancas Valley, Alajuela, 780 m (David Olson). Scale bar = 1 mm.

Specimen Habitat Summary

Found most commonly in these habitats: 69 times found in cloud forest, primary, along steep ridge near peak, 47 times found in ridgetop cloud forest, isolated peak with oak trees, 41 times found in tropical rainforest, with big trees, probably primary, 35 times found in cloud forest, primary, near ridgetop, 17 times found in cloud forest, 19 times found in tropical rainforest, some big trees, 16 times found in ridgetop cloud forest, 13 times found in cloud forest edge, near pasture, 14 times found in tropical rainforest, with some big trees, probably a mix of primary and secondary forest, 14 times found in tropical rainforest, mature, big trees, ...

Found most commonly in these microhabitats: 169 times ex sifted leaf litter, 159 times at bait, 1 times under epiphytes, 1 times nest in dead fern stem, 4 times Hojarasca, 1 times night foragers, 1 times ex sifted litter, 2 times bajo de M/07, 1 times Sobre Vegetacion, 1 times nest in rotten wood, 1 times nest in dead stick in litter, ...

Collected most commonly using these methods: 156 times baiting, 144 times miniWinkler, 20 times maxiWinkler, 5 times search, 6 times Winkler, 3 times bait, 4 times Mini Winkler, 3 times flight intercept trap, 2 times Malaise, 1 times beating, 1 times Sweeping, ...

Elevations: collected from 160 - 1550 meters, 848 meters average

Collect Date Range: collected between 1935-08-18 00:00:00.0 and 2020-01-10 00:00:00.0

Type specimens: paratypes: lacment140658

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