Simopelta species groups

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Revision as of 14:00, 21 April 2015 by Lubertazzi (talk | contribs) (curvata species complex)
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The information below is based on MacKay, W.P., MacKay, E.E. 2008. Revision of the ants of the genus Simopelta Mann (pp. 285-328). In Jíminez, E., Fernández, F., Arias, T.M. & Lozano-Zambrano, F.H. (eds). Sistematica, biogeografia y conservación de las hormigas cazadoras de Colombia: 609 pp. Instituto Alexander von Humboldt, Bogota. PDF

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curvata species complex

The workers in this species complex are mostly small, with the total length usually being less than 4 mm (S. mayri is larger). The anterior medial border of the clypeus nearly always has an elongated spine or at least forms a sharp point. The dorsum of the mesosoma is slightly depressed, and the petiole is narrow.

Simopelta bicolor, a southeastern Brasilian species, can be recognized, as the mandibles have more than four teeth, and the two apicalmost teeth are not noticeably separated from the other teeth. Simopelta minima is a tiny (Total Length 2.5 mm), southeastern Brasilian species. The other three species, S. curvata, S. mayri, and S. pergandei are larger (total length usually over 3 mm) and are found in Central America and South America. Simopelta mayri (Colombia) is larger (total length greater than 4 mm) and dark brown. Simopelta curvata (SE Brasil) is smaller (TL 3.5 mm) and has four mandibular teeth. Simopelta pergandei (Central and northern South America) is smaller (TL ~ 3 mm), medium brown, and has three mandibular teeth.

williamsi species complex

The workers of these ants are relatively large (total length approximately 4-5 mm). The anterior medial margin of the clypeus may be rounded, or slightly angulate, and may even have a spine. The mesosoma is broadly and strongly depressed between the pronotum and the propodeum, when viewed in profile. The petiole is relatively thick, when viewed in profile, and with the dorsal face sloping downwardly anteriorly.

Three of the species (S. breviscapa, S. fernandezi, and S. longinoda) have a relatively short mesosoma, with the length of the mesonotum being about 2/3 of the length of the dorsal face of the propodeum. The petiolar node (seen from above) is longer than broad, and noticeably narrowed anteriorly.

Simopelta longinoda from Costa Rica can be separated from the others by the relatively smooth and glossy dorsal face of the petiole. The node of the petiole of the southern Colombian Simopelta fernandezi, and Panamanian S. breviscapa is roughly sculptured. The short antennal scapes, which barely extend past the posterior lateral corners of the head, separate S. breviscapa from S. fernandezi (caution, S. longinoda also has short antennal scapes). The antennal scapes of S. fernandezi extend at least the first funicular segment past the posterior lateral corner.

The other species have a longer mesosoma, with the mesonotum being about the same length as the dorsal face of the propodeum. Two of these species are mostly smooth and shining. Of these, S. manni from northern Ecuador has coarse, dense punctures on at least the posterior part of the head; S. laevigata (Colombia) has only a few scattered, fine punctures in the same position. All of the other species are roughly sculptured, including the head.