Pheidole gymnoceras, Longino, J. T., 2009

Longino, J. T., 2009, Additions to the taxonomy of New World Pheidole (Hymenoptera: Formicidae)., Zootaxa 2181, pp. 1-90 : 34-37

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Pheidole gymnoceras

new species

Pheidole gymnoceras   HNS new species

Figure 8

Holotype major worker. Costa Rica, Heredia: 10km NE Vara Blanca, 10.23333°N 84.08333°W, ±2000m, 1500m, 9 Feb 2005 (J. Longino#5412) [ INBC, unique specimen identifier INB0003659251].

Paratypes: major and minor workers. Same data as holotype [ BMNH, CAS, EAPZ, ECOSCE, FMNH, INBC, JTLC, LACM, MCZ, MHNG, MIZA, MZSP, MEL, UCD, UNAM, ICN, USNM].

Geographic Range

Costa Rica.


With the morphometric profile of P. aciculata   HNS , minor workers very similar to the sympatric P. indagatrix   HNS . Minor worker: scape with all setae shorter than maximum width of scape versus with many erect setae longer than maximum width of scape ( aciculata   HNS , indagatrix   HNS ); hind femur with subdecumbent setae on dorsal surface versus with suberect setae on dorsal surface ( aciculata   HNS , indagatrix   HNS ). Major worker: relative to aciculata   HNS , inner hypostomal teeth more widely spaced; mesosoma less shiny; scapes with shorter setae; hind femur with dorsal setae subdecumbent versus suberect; sides of head with shorter, less erect setae; posterior margin of head more cordate.

Description of minor worker

Measurements (paratype): HL 0.83, HW 0.63, HLA 0.30, SL 1.17, EL 0.20, ML 1.11, PSL 0.10, PMG 0.04, SPL 0.04, PTW 0.13, PPW 0.19, CI 76, SI 185, PSLI 12, PMGI 5, SPLI 5, PPI 150.

Measurements (n=9): HL 0.78-0.85, HW 0.59-0.65, SL 1.10-1.17, CI 74-77, SI 176-190.

Mandible and clypeus smooth and shining; face with a few concentric rugae around antennal insertion, small patch of foveolate sculpture between frontral carina and compound eye; rest of face smooth and shining; margin of vertex rounded; occipital carina narrow, visible in full face view; scape with dense suberect setae but all shorter than maximum width of scape; promesonotal groove present, conspicuous; propodeal spines present; pronotum with patches of foveolate sculpture on humerus and anterior border, smooth and shining elsewhere; katepisternum and lateral and dorsal faces of propodeum foveolate overlain with inconspicuous rugulae; abundant setae on promesonotal dorsum; dorsal (outer) margin of hind tibia with abundant suberect setae, some longer than maximum width of tibia; dorsal face of hind tibia with setae appressed to subdecumbent; first gastral tergum smooth and shining; gastral dorsum with abundant suberect setae; color red brown.

Description of major worker

Measurements (holotype): HL 1.42, HW 1.39, HLA 0.40, SL 1.07, EL 0.24, ML 1.43, PSL 0.08, PMG 0.04, SPL 0.06, PTW 0.26, PPW 0.34, IHT 0.50, OHT 0.57, CI 98, SI 77, PSLI 6, PMGI 3, SPLI 4, PPI 130, HTI 88.

Mandible smooth and shiny; clypeus smooth and shining, flat, with distinct anterior notch; short longitudinal rugae between mandibular insertion and compound eye, a few concentric rugae around antennal insertion, grading to reticulate rugae between frontal carina and compound eye, rest of face smooth and shining; head with abundant short subdecumbent setae projecting from sides of head in face view; scape smooth and shining, terete at base, with abundant short subdecumbent setae, none longer than maximum width of scape; hypostomal margin straight; median tooth absent; inner hypostomal teeth thin and sharp, widely-spaced, much closer to outer hypostomal teeth than to midline; promesonotal groove present; propodeal spines present; pronotum smooth and shining with small irregular patches of faint foveolate sculpture; katepisternum smooth and shining anteriorly, grading to rugose-foveolate posteriorly and on lateral and dorsal faces of propodeum; dorsal (outer) margin of hind tibia with abundant suberect setae, some longer than maximum width of tibia; pilosity abundant on mesosomal dorsum; postpetiole in dorsal view globular; first gastral tergite smooth and shining, with abundant suberect setae; color red brown.


This species inhabits mid-elevation wet forest. During ALAS project sampling of the Barva transect it was found at the 1100m and 1500m sites. At the 1100m site it was most frequently captured in flight intercept traps, suggesting it is an epigaeic forager. At the 1500m site (Finca Murillo) a small queenrite nest was found beneath rotten wood; the workers had a foetid odor.


The name is in reference to the lack of longer erect setae on the scape of the minor worker.

Additional material examined

COSTA RICA: Heredia, 16km SSE La Virgen, 10°16'N, 84°05'W, 1100m (multiple collectors and collections).


Costa Rica, Santo Domingo de Heredia, Instituto Nacional de Biodiversidad (INBio)


United Kingdom, London, The Natural History Museum [formerly British Museum (Natural History)]


USA, California, San Francisco, California Academy of Sciences


Honduras, Tegucigalpa, Escuela Agricola Panamericana


USA, Illinois, Chicago, Field Museum of Natural History (also used by Finnish Museum of Natural History)


John T. Longino


USA, California, Los Angeles, Los Angeles County Museum of Natural History


USA, Massachusetts, Cambridge, Harvard University, Museum of Comparative Zoology


Switzerland, Geneva, Museum d'Histoire Naturelle


Venezuela, Maracay, Museuo del Instituto de Zoologia Agricola


Brazil, Sao Paulo, Sao Paulo, Museu de Zoologia da Universidade de Sao Paulo


USA, California, Davis, University of California, R.M. Bohart Museum of Entomology


Mexico, Mexico D.F., Universidad Nacional Autonoma de Mexico


Colombia, Bogota, Universidad Nacional de Colombia, Insituto de Ciencias Naturales de la Universidad Nacional


USA, Washington D.C., National Museum of Natural History, [formerly, United States National Museum]













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