Strumigenys nigrescens

Identification
Bolton (2000) - The unique dentition (see description below) is immediately diagnostic of nigrescens within the alberti-group, and will immediately separate smaller individuals of this species from Strumigenys furtiva.

Distribution
This taxon was described from Jamaica. It is also found in Mexico, Belize, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Cuba, Haiti, Dominican Republic, Trinidad and Tobago.

Nomenclature

 *  nigrescens. Strumigenys alberti var. nigrescens Wheeler, W.M. 1911a: 28 (w.) JAMAICA. Brown, 1953g: 98 (q.); Wheeler, G.C. & Wheeler, J. 1955a: 143 (l.). Combination in S. (Cephaloxys): Emery, 1924d: 325; in Smithistruma: Brown, 1953g: 96; in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 125. Raised to species and senior synonym of longipilis, nana: Brown, 1953g: 96. See also: Bolton, 2000: 157.
 * nana. Strumigenys (Cephaloxys) alberti var. nana Santschi, 1930e: 80 (w.) CUBA. Junior synonym of nigrescens: Brown, 1953g: 97.
 * longipilis. Strumigenys (Cephaloxys) alberti subsp. longipilis Weber, 1934a: 50 (w.) CUBA. Combination in Smithistruma: Brown, 1948e: 106. Junior synonym of nigrescens: Brown, 1953g: 97.

Description
Bolton (2000) - TL 1.8 - 2.0, HL 0.46 - 0.52, HW 0.36 - 0.42, CI 71 - 76, ML 0. 10 - 0.12, MI 21 - 24, SL 0.23 - 0.25, SI 60 - 65, PW 0.22 - 0.26, AL 0.42 - 0.52 (10 measured). Masticatory margin of mandible with characteristic dentition: basal lamella is followed by a small blunt first (basal) tooth; teeth 2, 4, and 6 are low, broad and broadly rounded apically; teeth 3, 5 and 7 are taller and narrower, triangular and acute. No secondary lamella present immediately distal of the basal lamella. Anterior clypeal margin broadly and very shallowly convex between the points where the outer margins of the closed mandibles intersect the clypeal margin, sometimes almost transverse. Apicoscrobal hair flagellate, long and fine, sometimes looped. Eye with 4 - 5 ommatidia in the longest row. Promesonotum with a variably developed median longitudinal carina. At maximum the carina distinct through entire length of pronotum and most of mesonotum; at minimum conspicuous only posteriorly on pronotum and anteriorly on mesonotum. Pronotum dorsally usually completely sculptured with fine costulae, punctation, or both. Occasionally the sculpture weak or even partially effaced anteromedially. Petiole node in dorsal view distinctly broader than long.

Type Material
Bolton (2000):

Holotype worker, JAMAICA: Mandeville (A.G. Wight) [examined].

Strumigenys (Cephaloxys) alberti var. nana Santschi, 1930: 80. Holotype worker, CUBA: Havana (A. Bierig) [not seen].

Strumigenys (Cephaloxys) alberti subsp. longipilis Weber, 1934a: 50. Holotype worker, CUBA: Cayamas, 6.3 (E.A. Schwarz). [examined].

Additional References

 * Baroni Urbani, C. & De Andrade, M.L. 2007. The ant tribe Dacetini: limits and constituent genera, with descriptions of new species. Annali del Museo Civico di Storia Naturale “G. Doria” 99: 1-191.