Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Major dorsal view (reduced, original).
Queen dorsal view (reduced, original); face view (reduced, original).
Line drawing of minor and major worker, from Kempf (1958).
Range
Mexico to Brazil (Kempf 1958). Costa Rica: seasonally dry portions of Guanacaste and Puntarenas Provinces.
Identification
Minor worker: eyes situated behind the scrobe, which terminates in front of the eye; in face view, lateral border of head with a deep, rounded excision that lodges the eye; hind basitarsus relatively short and broad, maximum width/maximum length 0.382-0.458; propodeal lamella usually broad, in the form of two or three rounded lobes.
Major worker: eyes situated behind the scrobe, which terminates in front of the eye; head with complete and strongly developed cephalic disk; cephalic disk continuous anteriorly, frontal carinae meet anteriorly at a linear incision, mandibles completely hidden beneath frontal carinae; color uniformly red brown; cephalic disk distinctly elongate; surface of cephalic disk shiny, with shallow foveae bearing appressed, linear setae.
Similar species: porrasi.
Natural History
This species prefers dry forest or scrubby habitats. It nests in live or dead stems. I have the following nest collections:
Nest in dead stick.
A sprawling vine had soft pith and was commonly inhabited by ants. A series of nest collections made, all from live stems.
Small treefall that had been down long enough for leaves to be dry and brown. Nest in hard dead wood.
Type Data
Cryptocerus pallens Klug 1824:206. Type locality: Brazil.
Notes
The pallens clade is recognized by three characters: 1) frontal carinae of minor workers broadly incised over eyes; 2) frontal carinae of minor workers concolorous with rest of head; and 3) disc of soldiers and queens covers mandibles (Andrade and Baroni Urbani 1999). There appear to be two species in the pallens clade in Costa Rica: pallens s.s. and porrasi. The minor workers of pallens have the hind basitarsus relatively short and broad, maximum width/maximum length 0.382-0.458. Minor workers of porrasi have the hind basitarsus relatively long and narrow, maximum width/maximum length 0.314-0.340. In Costa Rica, minor workers of pallens usually have the propodeal lamella broad, in the form of two or three rounded lobes. Minor workers of porrasi usually have the propodeal lamella narrower, in the form of two or three subtriangular teeth. Soldiers and queens of pallens have the disc moderately to strongly shiny, with widely-spaced foveae, and setae sublinear, decumbent within foveae. Soldiers and queens of porrasi have the disc mat or encrusted with debris, with more closely-spaced foveae, and erect, brush-shaped setae projecting from foveae.
Costa Rican material falls relatively neatly into these two species, with pallens occurring in Guanacaste province and the Central Valley, and porrasi occurring on the Osa Peninsula and the Atlantic slope. pallens is associated with dry forest and open habitats, porrasi with rainforest. However, one series from Maritza Biological Station is an interesting intermediate. In the minor worker, the dimensions of the hind basitarsus are intermediate, with maximum width/maximum length 0.37. Otherwise the minor workers and soldiers have the characters of typical pallens. Maritza is a sharp transition zone from lowland dry forest and open dry scrub, to evergreen montane forest. Thus it could well be that pallens and porrasi are parapatric in Costa Rica, perhaps forming hybrid zones at habitat boundaries between dry forest and moist or wet forest.
Measurements from three Costa Rican specimens, all minor workers (HBaL hind basitarsus length, HBaW hind basitarsus width, HBaI = 100*HBaW/HBaL):
Barcode HBaL HBaW HBaI locality
INBIOCRI001282757 0.300 0.112 37 Maritza
INBIOCRI002281713 0.298 0.126 42 Santa Rosa National Park
INBIOCRI002281702 0.316 0.105 33 Sirena, Corcovado National Park
Literature Cited
Andrade, M. L. de, and C. Baroni Urbani. 1999. Diversity and adaptation in the ant genus Cephalotes, past and present (Hymenoptera, Formicidae). Stuttgarter Beitrage zur Naturkunde Serie B (Geologie und Palaontologie) 271:1-889.
Kempf, W. W. 1958. New studies of the ant tribe Cephalotini (Hym. Formicidae). Stud. Entomol. (n.s.)1:1-168.
Klug, F. 1824. Entomologische Monographien. Berlin: Reimer, 242 pp.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.longinoj@evergreen.edu
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