Nylanderia pini

Known from higher elevation pine and mixed pine forests in the Dominican Republic. Collections have been taken from a nest in litter at the base of a tree, rotten wood, and under a rock and in the soil.

Identification
LaPolla and Kallal (2019) - Generally dark brown; gastral pubescence present only on the mid to posterior end of gastral tergite I, with anterior region of segment without pubescence; dorsal face of propodeum usually with a distinct fringe of pubescence.

Compare with: Nylanderia bibadia, Nylanderia fuscaspecula, Nylanderia metacista.

In our experience N. pini and N. fuscaspecula can be especially difficult to separate from each other. There are size differences, with N. pini being larger especially with regards to scape length (pini typically possesses a scape greater than 0.8 mm in length). Additionally, N. pini typically possesses a first gastral tergite with abundant pubescence beginning about midlength and continuing to the posterior margin of the segment. A fringe of pubescence is typically present along the dorsal face of the propodeum as well. However, we have seen specimens within nest series where the pubescence patterns do not match perfectly as discussed above and in these cases scape measurements should separate the two species. There was one location where both species occurred sympatrically and in fact were collected on the same day (Prov. La Vega, La Cienaga, ca. 1100 m, mixed HW-pine valley forest, Feb 1975, WL & DE Brown). Among these specimens, differences in worker pubescence and size noted above were easily observed. Workers of N. metacista are also likely to be confused with N. pini, but in all specimens we examined N. metacista workers always possess a dense layer of pubescence across gastral tergites I and II and this is never the case in N. pini.

Distribution based on Regional Taxon Lists
Neotropical Region: Dominican Republic.

Nomenclature

 *  pini. Nylanderia pini LaPolla & Kallal, 2019: 427, figs. 58-66 (w.q.m.) DOMINICAN REPUBLIC.

Worker
(n=7): TL: 2.40–2.80; HW: 0.52–0.62; HL: 0.69–0.73; EL: 0.17–0.18; SL:0.84– 0.86; WL:0.91–0.98; GL:0.83–0.9. SMC: 22–27; PMC: 3–6; MMC: 2–3. indices: CI: 84–87; REL:24–27; SI:136– 151; SI2: 19–22. Head: sides of head in full face view rounded and slightly broader posterior to eyes; posterolateral corners rounded; posterior margin relatively straight; anterior clypeal margin emarginate; median ocellus sometimes present; eyes well-developed. Mesosoma: in lateral view, pronotum convex; anterior margin of mesonotum distinctly raised above posterior pronotal margin; metanotal area with a short flat area before spiracle; dorsal face of propodeum slightly convex; dorsal face of propodeum slightly lower than mesonotum in lateral view. Color and pilosity: dark brown, with lighter brownish-yellow to yellow funiculus, mandible, mesocoxa/trochanter, metacoxa/trochanter, distal ends of femora and tibiae, and tarsi; occasionally lighter brown around promesonotal junction; cephalic pubescence sparse, denser on posterolateral corners and posterior and anterior of eyes; legs and mesonotum pubescent; dorsal face of propodeum usually with distinct fringe of pubescence; gastral pubescence present only on mid to posterior end of gastral tergite I; anterior portion without pubescence; remaining gastral tergites with abundant pubescence.

Queen
(n=1): TL: 4.1; HW: 0.83; HL: 0.83; EL: 0.25; SL: 0.97; WL: 1.5; GL: 2.1. SMC: 14; PMC: 5; MMC: 6; MtMC: 3. indices: CI: 100; REL: 30; SI: 117.

Generally, as in worker with modifications expected for caste and with the following noted difference: slightly lighter brown (to yellow) than seen in workers.

Male
(n=3): TL: 1.6–2.2; HW: 0.55–0.57; HL: 0.51–0.57; EL: 0.21–0.23; SL: 0.74–0.76; WL: 0.85–1.0; GL: 0.87–1.11. SMC: 10–12 PMC: 0; MMC: 6–12; MtMC: 2–3. indices: CI: 99–107; REL: 40–42; SI: 134–147.

Head: sides of head in full face view rounded; posterior margin rounded; clypeus emarginate anteriorly; mandible with distinct apical tooth and much smaller subapical tooth adjacent to apical tooth; basal angle rounded and indistinct. Mesosoma: in lateral view, dorsal margin of mesoscutum same as height as dorsal margin of mesoscutellum; propodeum steeply sloping without distinct dorsal and declivitous faces. Genitalia: gonopod apex coming to triangular point in lateral view; in dorsal view, gonopod margin curves away slightly from penial sclerite; digitus with pointed apex that bends away from penial sclerite; cuspis tubular, rounded at apex bending sharply toward digitus; anteroventral process of penial sclerite coming to a point with ventral margin of process emarginate; valvura of penial sclerite placed ventral to midline. Color and pilosity: color brown with darker brown head, pronotum, and gaster; remainder of body yellow to light brown; head, scapes, mesosomal notum, legs and gastral dorsum with a layer of pubescence.

Type Material
Holotype worker, DOMINICAN REPUBLIC: Parque Nacional Armando Bermúdez; 19° 04.044’N, 70° 51.830’W; elev. 1037 m; moss and soil under tree; 07.viii.2009; S.A. Schneider (USNMENT007544798). 4 paratype workers, 1 paratype queen and 1 paratype male with same locality data as holotype (specimens are from the same nest as holotype) (NMNH & ).

Etymology
Species epithet is from the plural form of pinus (L. = pine), named for the dominant trees in the forests in which this species was found.

References based on Global Ant Biodiversity Informatics

 * LaPolla J. S., and R. J. Kallal. 2019. Nylanderia of the World Part III: Nylanderia in the West Indies. Zootaxa 4658: 401-451.