Solenopsis longinoi

Solenopsis longinoi was collected in litter from lowland, oak, ridge and cloud forests in Costa Rica. It is listed as Solenopsis JTL-018 (Longino, Ants of Costa Rica website) and was reported in the website to be collected in montane forest of Cordillera de Talamanca at 1200 and 1670 m from Winkler samples of sifted litter in Costa Rica.

Identification
A New World thief ant that is a member of the stricta species complex.

Pacheco and Mackay (2013) – Worker - This is a moderately large and hairy, concolorous dark brown species. The head is subquadrate and finely punctate. The lateral clypeal teeth are well developed while the extralateral teeth are absent. The scape is long and reaches the posterior lateral corner of the head. The eyes have 5-7 ommatidia. The defining characters of this species are the deep notopropodeal depression and dome-shaped dorsopropodeum.

It would be unlikely to confuse S. longinoi with other members of the stricta complex based on its unusually dome-shaped propodeum. This trait is unique among the thief ants in the New World and makes S. longinoi easily recognized. Additional characteristics that make this species unique are its relatively long scape and elongated peduncle.

Keys

 * Key to New World Solenopsis Species Complexes
 * Key to workers of the stricta species complex / Clave para las obreras del complejo stricta

Distribution based on Regional Taxon Lists
Neotropical Region: Costa Rica.

Castes
Known only from the worker caste.

Nomenclature

 *  longinoi. Solenopsis longinoi Pacheco & Mackay, 2013: 208, figs. 154-155, map 36 (w.) COSTA RICA.

Worker
Measurements (n=6). TL 2.40-2.52 (2.49); HL 0.606-0.618 (0.612); HW 0.504-0.510 (0.509); EL 0.060-0.066 (0.064); ED 0.042-0.048 (0.044); SL 0.480-0.498 (0.491); FSL 0.228-0.240 (0.234); CI 81.6-84.2 (83.2); SI 77.7-81.4 (80.2); PL 0.120-0.132 (0.122); PW 0.126-0.138 (0.132); PI 86.9-95.7 (92.5); PPL 0.174-0.180 (0.178); PPW 0.192-0.198 (0.196); PPI 87.9-93.8 (90.8); WL 0.540-0.570 (0.552); PSL 0.042-0.048 (0.045); PSW 0.042.

Moderately large; concolorous dark brown, with lighter brown appendages; head subquadrate, posterior margin and sides slightly convex, finely punctated; lateral clypeal teeth well developed, medial and extralateral teeth absent; clypeal carinae well defined, extend between frontal lobes; scape long, reaching posterior lateral corner of head; eye medium sized, 5-7 ommatidia; pronotum finely punctate (punctures barely visible), smooth and shiny between punctures; mesopleuron smooth and shiny; propodeum dome-shaped, striated basally; petiole widened when viewed laterally, peduncle elongate from propodeum, lacking ventral tooth or flange; postpetiole wider than petiolar peduncle viewed dorsally, lacking tooth or flange ventrally; both petiole and postpetiole smooth and shiny.

Moderately pilose, hairs yellow to light brown; head with erect and suberect hairs of various lengths (0.030-0.120 mm); scape with numerous suberect hairs (0.030-0.060 mm); pronotum with erect hairs of various lengths (0.030-0.150 mm); long (up to 0.180 mm) suberect hairs on petiole, postpetiole and gaster that curve posteriorly.

Type Material
Holotype worker and one paratype worker, Costa Rica, San Jose, Pan American Highway Km 117, 9°36'N 83°42'20"W, 15-vi-1998, R. Anderson #18657.

Etymology
Named to honor our friend and colleague John (Jack) Longino, one of the foremost ant authorities who has done the most important work on Costa Rican ants.

References based on Global Ant Biodiversity Informatics

 * Longino J. T. L., and M. G. Branstetter. 2018. The truncated bell: an enigmatic but pervasive elevational diversity pattern in Middle American ants. Ecography 41: 1-12.
 * Longino J. et al. ADMAC project. Accessed on March 24th 2017 at https://sites.google.com/site/admacsite/
 * Pacheco J. A., and W. P. Mackay. 2013. The systematics and biology of the New World thief ants of the genus Solenopsis (Hymenoptera: Formicidae). Lewiston, New York: Edwin Mellen Press, 501 pp.