Nylanderia pubens ( Forel, 1893 )

Kallal, Robert J., 2019, Nylanderia of the World Part III: Nylanderia in the West Indies, Zootaxa 4658 (3), pp. 401-451 : 430-433

Nylanderia pubens ( Forel, 1893)

Figs. 67–69 (worker); 70–75 (male)

Prenolepis (Nylanderia) fulva r. pubens Forel, 1893: 338 (w.q.m.) 5 workers, 1 queen and 2 male syntypes, ST. VINCENT (MHNG) (examined; lectotype male here designated; specimen on pin with two separate points; point with lectotype marked with small red dot. Combination in Paratrechina (Nylanderia) : Emery, 1925: 222; in Nylanderia: Kempf, 1972: 167 ; in Paratrechina: Trager, 1984: 143 ; in Nylanderia: LaPolla, Brady & Shattuck, 2010: 127 . Junior synonym of Nylanderia fulva: Creighton, 1950: 406 . Revived from synonymy and raised to species: Trager, 1984: 143.

Worker diagnosis: Large species (TL:>2.5), brown, and entire body covered in dense pubescence that gives body a dull and shaggy appearance shaggy.

Compare with: N. bourbonica , N. fulva

WORKER. Measurements (n= 2): TL: 2.60–2.90; HW: 0.64–0.67; HL: 0.67–0.76; EL: 0.18–0.19; SL: 0.88– 0.9; WL: 0.90–0.94; GL: 1.05–1.20. SMC: 18–26; PMC: 4–6; MMC: 2–3. Indices: CI: 88–95; REL: 25–28; SI: 133–137; SI2: 20–21.

Head: sides of head in full-face view nearly parallel; posterolateral corners rounded; posterior margin rounded distinctly emarginate medially; anterior clypeal margin emarginate; three ocelli present; eye well-developed. Mesosoma: in lateral view, pronotum convex; anterior margin of mesonotum more or less even with posterior pronotal margin; metanotal area with a short flat area before spiracle; dorsal face of propodeum slightly convex to almost flat in some specimens; dorsal face of propodeum lower than mesonotum in lateral view. Color and pilosity: brown; entire body covered with dense pubescence, giving it dull appearance; in many places across the body pubescence becomes decumbent and long, especially on pronotum, mesonotum and gaster giving shaggy appearance.

QUEEN. Measurements (n=1): TL: N/A; HW: 1.04; HL: 0.99; EL: 0.31; SL: 1.1; WL: 1.7; GL: N/A. SMC: 21 PMC: 5; MMC: 23. Indices: CI: 105; REL: 32; SI: 106.

Generally, as in worker with modifications expected for caste.

MALE. Measurements (n=1): TL: 2.40; HW: 0.57; HL: 0.63; EL: 0.28; SL: 0.99; WL: 1.10; GL: 1.30; SMC: 10; PMC: 0; MMC: 15. Indices: CI: 86; REL: 42; SI: 150.

Head: sides of head in full face view nearly parallel becoming slightly broader posterior to eyes; posterior margin straight to slightly rounded; clypeus emarginate anteriorly; mandible with distinct apical tooth and usually a much smaller 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 steeply sloping without distinct dorsal and declivitous faces. Genitalia: gonopod apex triangular but broadly rounded in lateral view; in dorsal view, gonopod margin curves away from penial sclerite; digitus with broadly rounded apex nearly parallel with penial sclerite; cuspis tubular, rounded at apex bending sharply toward digitus; anteroventral process of penial sclerite broadly rounded; valvura of penial sclerite placed ventral to midline (fig. 76). Color and pilosity: nearly uniform light brown to brown; head, pronotum and gaster often slightly darker with a slightly lighter posterior portion of mesosoma; entire body cover with a layer of dense pubescence.

Other material examined: ANGUILLA: Brimegin , True Eyes Road, 18.236 N, 63.051 W, 21 May 2006, #95, JK Wetterer ; GRENADA: Grand Etang , Morne La Bay, 9 Nov 2003 ( JK Wetterer); Grand Etang, Lookout Trail, 8 Nov 2003 ( JK Wetterer); Coral Cove, 11 Nov 2003 ( JK Wetterer) .

Notes: This former subspecies of N. fulva was elevated to full species by Trager (1984) based primarily on differences in shape and pilosity of the male gonopods. Nylanderia pubens has gonopods that are more rounded at the distal apex, and much more setose. These morphological differences, as well molecular markers, were used by Gotzek et al. (2012) to support Trager’s assertion that N. fulva and N. pubens are in fact separate species. Based on the Gotzek et al. (2012) study, N. fulva and N. pubens can putatively be considered sister species. Dissection of male N. fulva and N. pubens genitalia completed in this study revealed significant differences in the shape of the penial sclerites as well as in the shape of the 9 th sternites (fig. 76). It is important to note that while we had abundant male N. fulva specimens to examine (we dissected 10 specimens from different locations), we only had access to one male N. pubens we could dissect. The penial sclerites of N. pubens are more elongated than those of N. fulva and the 9 th sternite is longer (along its anterior-posterior axis) and more shield-like in overall shape in N. pubens compared with N. fulva .

Unfortunately, it does not seem possible to separate workers of the species based on morphology. Despite the fact that Trager (1984) noted some differences in the heads of N. pubens workers from those of N. fulva stating N. pubens had more emarginate posterior margins, less overall pubescence and the head lacking punctation, we have not found that those differences reliably separate the species. It is not uncommon for sister species in Nylanderia to display differences in male morphology, while workers are difficult to impossible to distinguish morphologically. A well-known example of this is observed in two widespread North American species, N. terricola and N. vividula ( Kallal & LaPolla, 2012) .

There has been much interest in the separation of N. fulva and N. pubens recently due to the rapid spread of N. fulva across the southern United States ( Gotzek et al. 2012; Kumar et al. 2015). While N. fulva is the species of recent interest, it is unclear if N. pubens is native to the West Indies either. It seems unlikely to be native based on the fact N. pubens is always found in lowland, highly disturbed places in the West Indies. Additionally, the fact that N. pubens is very likely the sister species to N. fulva , which almost certainly is native to southcentral South America, further supports the notion N. pubens is South American in origin. At one time populations of N. pubens were established in Florida ( Trager, 1984), but those populations appear to have since been extirpated from the state. Specimens of N. pubens were also found in the National Museum of Natural History collection (Smithsonian Institution) that came from greenhouses in Washington D.C. around the turn of the 20 th Century. Why N. fulva is now the species primarily being moved around the Western Hemisphere by human activities and not N. pubens is an interesting question.

In the interest of nomenclatural stability, a lectotype worker of Nylanderia fulva is here designated from the 12 worker syntype series from NHMW that were examined. Label data is: [ Brazil] Novara; 1857-59; Reise ( USN- MENT007553598 ) .

Figures

FIGURES 67–69. Nylanderia pubens worker CASENT0104862 (images from www.Antweb.org taken by April Nobile). Lateral, full-face, and dorsal view of the body.