Nylanderia semitincta

The type material was collected from a nest in rotting wood in a dwarf forest.

Identification
LaPolla and Kallal (2019) - Coloration distinct with head, pronotum, often anterior mesonotum and gaster brown, contrasting with yellow remainder of mesosoma (propodeum especially bright yellow in many specimens) and legs.

Compare with: Nylanderia disatra.

This species is easily separated from the other native Puerto Rican species, Nylanderia microps, which is much larger, yellow, covered in many macrosetae across the pronotum and mesonotum and has very small eyes. Both species do occur in sympatry in at least the El Yunque National Forest and possibly other rainforest areas of the island, but N. semitincta is currently only known from El Yunque. Although not as strongly contrasting (not as dark brown), the coloration pattern seen in N. semitincta is similar to N. disatra known from the Dominican Republic. Although in N. disatra workers the head is very dark brown and the entire mesosoma is bright yellow. Overall, the male genitalia between the two species are also fairly similar (with some obvious differences in gastral pubescence and shapes of genitalic structures especially the volsellar lobes and the digiti), which may suggest these two species are closely related.

Distribution based on Regional Taxon Lists
Neotropical Region: Puerto Rico.

Nomenclature

 *  semitincta. Nylanderia semitincta LaPolla & Kallal, 2019: 433, figs. 77-85 (w.q.m.) PUERTO RICO.

Worker
(n=3): TL: 2.12–2.30; HW: 0.47–0.52; HL: 0.52–0.59; EL: 0.12–0.15; SL: 0.61– 0.68; WL: 0.66–0.74; GL: 0.92–1.00. SMC: 20–22 PMC: 2–4; MMC: 2. indices: CI: 85–91; REL: 22–25; SI: 129–136; SI2: 19–22.

Head: sides of head in full face view nearly parallel; posterolateral corners rounded; posterior margin straight and slightly emarginate medially; anterior clypeal margin with slight median emargination; three ocelli present; eye well-developed. Mesosoma: in lateral view, pronotum convex; anterior margin of mesonotum raised slightly 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: head, pronotum, often anterior mesonotum and gaster brown, contrasting distinctly with yellow remainder of mesosoma (propodeum often brightest yellow) and legs; antennae and mandibles lighter brownish-yellow; pubescence sparse except on small patches around eyes; scapes and legs with abundant pubescence.

Queen
(n=1): TL: 4.40; HW: 0.72; HL: 0.71; EL: 0.23; SL: 0.78; WL: 1.4; GL: 2.3. SMC: 8 PMC: 3; MMC: 25. indices: CI: 101; REL: 32; SI: 109.

Generally, as in worker with modifications expected for caste.

Male
(n=2): TL: 1.90–2.00; HW: 0.46–0.48; HL: 0.43–0.46; EL: 0.17–0.19; SL: 0.54–0.55; WL: 0.70–0.72; GL: 0.78–0.83. SMC: 3–5 PMC: 0; MMC: 5–7. indices: CI: 103–106; REL: 35–43; SI: 114–118.

Head: sides of head in full face view rounded; posterior margin straight rounded; clypeus evenly rounded anteriorly; mandible distinct apical tooth and much smaller, often very indistinct, subapical tooth adjacent to apical tooth; basal angle sharp and distinct. Mesosoma: in lateral view, dorsal margin of mesoscutum same as height as dorsal margin of mesoscutellum; propodeum sloping without distinct dorsal and declivitous faces. Genitalia: gonopod apex coming to triangular point in lateral view; in dorsal view, gonopod margin curves away 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 broadly rounded; valvura of penial sclerite placed approximately at midline. Color and pilosity: color as in worker but not as distinctly contrasting (colors closer to each other in tone) with brown head (including antennae), pronotum, mesoscutum, and gaster; remainder of body yellow to light brown; head, scapes and mesonotum with a layer of abundant pubescence.

Type Material
Holotype worker, PUERTO RICO: El Yunque National Forest, N 18° 16.295’, W 65° 45.877’, elev. 3054 ft., dwarf forest, nest in rotting wood, 15 July 2008, J.S. LaPolla (USNMENT00754809) ; 4 paratype workers, 1 paratype queen, 2 paratype males same locality as holotype (specimens are from the same nest as holotype) (NMNH & ).

Etymology
Species epithet is a combination of semi- (L. = half) and tincta (L. = colored), named for the two toned appearance of this species.

Determination Clarifications
This species is included in the phylogeny of Gotzek et al. (2012) as Nylanderia n.sp. PR1 where it is sister to Nylanderia microps and not to Nylanderia disatra.

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.