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10a. Gaster with long flexuous setae at least on anterior third, usually over entire surface: 20
10b. Gaster devoid of erect setae: 30
20a. Weber's length around 0.7mm; metanotal groove not impressed: scrobiculatus
20b. Weber's length about 1.0mm; metanotal groove impressed; erect setae very dense and relatively shorter on first gastral tergum: laticeps
20c. Weber's length about 1.0mm; metanotal groove impressed; erect setae relatively sparser and longer on first gastral tergum: grandis
30a. Dorsum of postpetiole irregularly rugose, without a raised triangular boss medially, and with more than 10 evenly distributed erect setae; dorsum of mesosoma with irregular short rugae: longinoi
30b. Dorsum of postpetiole with a raised, subtriangular boss medially, and with a single row of about 6 long flexuous setae along anterior margin; dorsum of mesosoma with rugae organized into somewhat continuous wavy rugae, transverse on anterior pronotum, grading to longitudinal on rest of promesonotum: 40
40a. Cephalic dorsum with dense, subparallel rugae; compound eyes relatively large (eye length greater than 0.15mm), with about 10 facets at maximum diameter; mesosoma length (WL) greater than or equal to 0.85mm; dorsum of postpetiole entirely smooth and shining; gaster much darker than the rest of body: regularis
40b. Cephalic dorsum with rather sparser, vermiculate rugae; compound eyes smaller (eye length less than or equal to 0.15mm), with about 7 facets at maximum diameter; mesosoma length (WL) less than 0.85mm; dorsum of postpetiole with short and weak rugulation laterally; gaster slightly darker than the rest of body: haskinsi
Queens: (the queens of laticeps and regularis are unknown)
10a. Weber's length about 1.3mm: grandis
10b. Weber's length less than 1mm: 20
20a. First gastral tergum uniformly covered with long flexuous setae: scrobiculatus
20b. First gastral tergum with erect setae sparse to absent on posterior half: 30
30a. First gastral tergum with about 50 long erect setae on anterior half; postpetiole dorsum irregularly rugose, without raised subtriangular boss medially: longinoi
30b. First gastral tergum with about 10 long erect setae, in an anterior band near the postpetiolar insertion; postpetiole dorsum with a raised subtriangular boss medially: haskinsi
Some relevant papers:
Borgmeier, T. 1957. Myrmecologische Studien, I. Anais da Academia Brasileira de Ciencias 29:103-128.
Feitosa, R. M., and C. R. F. Brand‹o. 2008. A taxonomic revision of the Neotropical myrmicine ant genus Lachnomyrmex Wheeler (Hymenoptera: Formicidae). Zootaxa 1890:1-49.
Smith, M. R. 1944. The genus Lachnomyrmex, with the description of a second species. Proceedings of the Entomological Society of Washington 46:225-228.
Weber, N. A. 1950. New Trinidad myrmicinae, with a note on Basiceros Schulz (Hymenoptera, Formicidae). American Museum Novitates 1465:1-6.
Page author: John T. Longino longinoj@evergreen.edu
Date of this version: 1 April 2009.