Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Identification
Minor worker: head length 0.66-0.74mm, head width 0.0.51-0.59mm, scape length 0.94-1.07mm, Webers length 0.89-0.99mm (n=4). Head with vertex collar present but small; promesonotal and metanotal grooves well impressed; propodeal spines spiniform and long or shorter and subtriangular (see below); face smooth and shining; pronotum smooth and shining; anepisternum differentiated from katepisternum, more impressed; anepisternum with a few coarse rugae, punctation faint or absent; katepisternum foveolate; propodeum foveolate on sides and dorsum; pilosity long, flexuous.
Major worker: head length 0.97-1.23mm, head width 0.96-1.17mm, scape length 0.95-0.98mm (n=4). Face smooth and shiny; moderately abundant long flexuous setae on margins of head.
Variation: Character variation among the few collections of this "species" is such that we have vacillated between splitting and lumping them. The extremes of variation may be found at a single location (La Selva Biological Station). In two collections from baits, the minor has long spiniform propodeal spines. On the major worker of this form, the head is relatively short, such that the scapes extend beyond the vertex margin, and the sides of the postpetiole are not produced as triangular projections (this form is shown in the images for this page). In one collection from a nest in soil, the minor has relatively short, subtriangular propodeal spines. The major worker has a relatively longer head, such that the scapes fall short of the vertex margin, and the sides of the postpetiole are produced and triangular. A fourth collection is intermediate. The minor worker has propodeal spines relatively short and subtriangular. On the major worker, the head is intermediate, with the scapes just reaching the vertex margin, and the sides of the postpetiole are not produced as triangular projections. Bivariate scatter plots of measurements from these four collections are spread along single lines of allometry, showing no tendency to form separate clusters of points or displaced allometric lines.
Range
Costa Rica (Atlantic slope to 800m, mid-elevation southern Pacific slope).
Natural History
tanyscapa inhabits mature wet forest. Nests are in the soil. Foragers come to baits on the ground, and are also observed foraging on low vegetation.
Selected Records
La Selva: mature forest; nest in soil.
La Selva: At tuna baits.
Rio Penas Blancas (800m): mature wet forest; nocturnal foragers.
Osa Peninsula (700m): foragers.
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
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