Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Range
interrupta complex, including continua: throughout tropical America; Mexico to southern Brazil, Jamaica. interrupta sensu stricto according to Lattke (1995): Colombia, Costa Rica, Honduras, Jamaica. Costa Rica: wet forest sites throughout the country, to 1700m.
Identification
Promesonotal suture very faintly impressed, not breaking sculpture; scapes fail to reach margin of vertex when laid back; dorsal surface of mandible smooth and shiny; propodeal dorsum longitudinally striate; anterior margin of narrow anterior apron of clypeus straight to distinctly concave in the middle, terminating laterally in rounded corners; anteroventral petiolar process with posterior lobe or square-cut corner, and with distinct fenestra; HW less than 0.9mm.
Notes
continua and interrupta are both Mayr species, from adjacent pages in the same 1887 publication. The type localities are Santa Catarina, Brazil for continua, and "Patr. ? M. Dresd./Sudamerika" for interrupta. In Brown's revision the two species are differentiated mainly by size. Lattke (1995) distinguishes continua and interrupta by the presence or absence of a metacoxal tooth. Costa Rica material that I identify as various forms within this complex are variable in this character, and I cannot easily ally them with one or the other. I currently recognize four forms, which show patterns of broad sympatry across Costa Rica. These "forms" are based on relatively few collections, and their further definition will require additional collections. The forms are:
JTL-001 (cf. interrupta): HW across eyes 0.87mm; katepisternum striate; metacoxal tooth a low ridge; subpetiolar process with anterior margin deep and broadly rounded, posterior margin sinuous (i.e. posteroventral tooth or corner, present in forms with subquadrate process, greatly reduced); dorsum of petiole with median shiny area among irregular rugae; AT3 coarsely foveate anteriorly, grading to costate posteriorly; AT4 irregularly foveate/costate with posteromedian shiny area. Monteverde cloud forest.
JTL-002 (cf. interrupta): HW across eyes 0.52mm; katepisternum shiny; metacoxal tooth a low ridge; subpetiolar process subquadrate, with anteroventral margin rounded, posteroventral margin a sharp corner; dorsum of petiole longitudinally costate; AT3 longitudinally costate; AT4 costate anteriorly, smooth posteriorly. Pacific lowlands (Carara, Manuel Antonio), Penas Blancas.
JTL-003 (cf. interrupta): HW across eyes 0.73mm; katepisternum shiny; metacoxal tooth a low ridge or moderately developed into a triangular tooth; subpetiolar process with anteroventral margin in the form of a ventrally-directed triangular tooth, posteroventral margin a sharp corner; dorsum of petiole longitudinally costate; AT3 longitudinally costate; AT4 costate anteriorly, smooth posteriorly. San Vito, Cerro Pittier, Penas Blancas.
JTL-004 (cf. interrupta): HW across eyes 0.65mm; katepisternum shiny; metacoxal tooth a low ridge; subpetiolar process with anterior margin deep and broadly rounded, posterior margin sinuous (i.e. posteroventral tooth or corner, present in forms with subquadrate process, greatly reduced); dorsum of petiole longitudinally costate; AT3 longitudinally costate; AT4 costate anteriorly and posteriorly, with posteromedian smooth shiny area. San Vito.
I have one Venezuelan specimen in this group, examined by Lattke and identified as continua (but no Lattke ID label). It has a metacoxal tooth that is more developed than any Costa Rican material, is small (like JTL-002) and ferrugineus, but otherwise is a small, light-colored version of JTL-001 (costae on the pleural regions, similar ventral petiolar process). I have a Colombian specimen which was identified by Lattke as interrupta. It is nearly identical to Costa Rican JTL-002, with the exception of a well-developed metacoxal tooth, like the Venezuelan specimen.
Gnamptogenys interrupta is encountered infrequently, as occasional workers in berlese or Winkler samples of litter from the forest floor.
Type data
Ectatomma (Gnamptogenys) interruptum Mayr 1887:543. Type worker: "Patr. ? M. Dresd./Sudamerika."
Literature Cited
Brown, W. L., Jr. 1958. Contributions toward a reclassification of the Formicidae. II. Tribe Ectatommini (Hymenoptera). Bulletin of the Museum of Comparative Zoology 118:175-362.
Lattke, J. E. 1995. Revision of the ant genus Gnamptogenys in the New World (Hymenoptera: Formicidae). Journal of Hymenoptera Research 4:137-193.
Mayr, G. 1887. Sudamerikanische Formiciden. Verhandlungen der zoologische-botanische Gesellschaft Wien 37:511-632.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.longinoj@evergreen.edu
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