Strumigenys oconitrilloae

At La Selva Biological Station, while night collecting in the arboretum, I found a nest under a bark flap at the base of a large Pithecellobium tree. I saw a worker carrying a collembolan prey item at the time of collection. Workers have been taken in Winkler and Berlese samples and a flight intercept trap at La Selva and at the 300 m site on the Barva transect in Braulio Carrillo National Park. A dealate queen was collected in a canopy fogging sample at La Selva. (Longino 2006)

Identification
Longino (Ants of Costa Rica) - Mandibles in full-face view linear, elongate and narrow; ventral surface of petiole without spongiform tissue; leading edge of scape with freely projecting hairs, these relatively thin and strongly curved; inner margin of mandible without a tooth or distinctly enlarged denticle at or near the midlength; labral lobes short, trigger hairs at apices of lobes long; outer margins of mandibles relatively straight; mandibles thick, with inner margin convex; close to the apical fork is a small preapical tooth, followed closely by 3-5 very small denticles; ground pilosity conspicuous and abundant, particularly on head; hairs on head spoon-shaped and reclining; in profile dorsal mesosoma with only a single pair of standing hairs (in addition to those at humeri), on mesonotum; first gastral sternite smooth. Similar to: Strumigenys subedentata, Strumigenys cascanteae, Strumigenys paniaguae, Strumigenys gundlachi, Strumigenys eggersi and Strumigenys trieces.

Longino (2006) - Intensive collecting at La Selva Biological Station and the Barva Transect has revealed a complex of five closely similar but consistently separable species related to Strumigenys subedentata. Strumigenys subedentata occurs throughout the Neotropics, usually in lowland wet to somewhat seasonal sites, in both mature and second growth forests. It is often collected in samples of litter and rotten wood from the forest floor. Strumigenys trieces occurs on the Atlantic slope of Central America from Nicaragua to Panama, from sea level to 1100 m elevation. It occurs most abundantly in mature wet forest where, like S. subedentata, it inhabits leaf litter and rotten wood on the forest floor. The three new species described here – Strumigenys oconitrilloae, Strumigenys cascanteae, and Strumigenys paniaguae – occur as a graded series of elevational specialists, with S. oconitrilloae occurring at La Selva and the 300 m site on the Barva Transect, S. cascanteae occurring at the 300 m site and at a 600 m site in the nearby Arenal National Park, and S. paniaguae occurring at the 500 m, 1100 m, and 1500 m sites on the Barva Transect. These three all show a tendency to be arboreal, nesting under bark flaps or epiphytes and rarely occurring in samples of litter and rotten wood from the forest floor. A sixth species in this complex, Strumigenys connectens (Kempf, 1958), occurs in Colombia and Ecuador.

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

Nomenclature

 *  oconitrilloae. Pyramica oconitrilloae Longino, 2006b: 139, figs. 17, 18, 21 (w.q.) COSTA RICA. Combination in Strumigenys: Baroni Urbani & De Andrade, 2007: 125

Worker
Holotype: ML 0.261, HL 0.506, HW 0.415, SL0.237, MeL 0.512.

With the characters of the Strumigenys gundlachi group, sensu Bolton (2000); inner margin of mandible evenly convex for nearly entire length; preapical mandibular dentition consisting of one small sharp tooth immediately proximal to apicodorsal tooth, followed by up to five minute denticles; eye with about 15 ommatidia; setae on leading edge of scape thicker apically but not broadly fan-shaped, first two setae (starting at base) strongly curving toward scape apex, next two strongly curving toward scape base, fifth curving toward scape apex; ground pilosity of clypeus, face, and promesonotum abundant, remiform, subdecumbent; dorsal face of propodeum and gastral dorsum lacking ground pilosity; katepisternum smooth and shiny, rest of mesosoma, head, petiole, and postpetiole punctate; metanotal groove not impressed, such that promesonotum and dorsal face of propodeum form single flat surface; gastral dorsum smooth and shiny with short, sparse basal costulae, plus variable extent of fine longitudinal striolation on basal fourth or less; pairs of stout clavate setae on sides of head at upper scrobe margin, upper face near vertex margin, pronotal humeri, mesonotum, and petiolar node; postpetiole and gaster with abundant stout clavate setae; color orange.

Queen
ML 0.273, HL 0.522, HW 0.436, SL0.253, MeL 0.603.

Similar to worker in mandibular structure, surface sculpture, pilosity, and color; katepisternum smooth and shiny as in worker, rest of side of mesosoma punctate; gastral dorsum longitudinally striolate in basal fourth.

Type Material
Holotype worker: Costa Rica: Heredia Prov., La Selva Biological Station (10° 26' N, 84° 01' W), 50 m elevation, 28.X.1991, leg. J. Longino#3152, specimen code JTLC000007866. Paratypes: 5 workers, same data as holotype, JTLC00 0007867, INBIOCRI001224829 , JTLC 000007869 , INBIOCRI001224828 , JTL C000007868 ; dealate queen, same locality as holotype, 11.V.2000, leg. Project ALAS FOT/49/1-40, INBIO CRI002281849 ; 1 worker, Costa Rica: Heredia Prov., 11 km ESE La Virgen (10° 21' N, 84° 03' W), 300 m elevation, 16.II.2004, leg. Project ALAS 03/B/BV/019, INB0003624227 (JTLC); 1 worker, same data but 15.III. 2004, 03/B/BV/049, INB0003624223 ; 1 worker, same data but 10.IV.2004, 03/WF/02/06, INB0003621500 ; 1 worker, same data but 13.II.2004, 03/TN/03/003, INB0003619372.

Etymology
Named for Nelci Oconitrillo, Project ALAS Parataxonomist from 1994 to 2001.

References based on Global Ant Biodiversity Informatics

 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * INBio Collection (via Gbif)
 * Longino J. T. 2006. New species and nomenclatural changes for the Costa Rican ant fauna (Hymenoptera: Formicidae). Myrmecologische Nachrichten 8: 131-143.