Paratrechina zanjensis, LaPolla & Hawkes & Fisher, 2013

LaPolla, John S., Hawkes, Peter G. & Fisher, Jonathan N., 2013, Taxonomic review of the ant genus Paratrechina, with a description of a new species from Africa, Journal of Hymenoptera Research 35, pp. 71-82 : 75-76

Paratrechina zanjensis sp. n. Figs 4-6 , 8 , 9 (worker)

Holotype worker.

TANZANIA: Ruvuma Region, Namtumbo District, Mkuju River, 855m, 10.07400S, 36.57959E ± 100m, 27-29.xi.2011, MKU2011-3.1 (P Hawkes, J Fisher) (SAMC: SAM-HYM-C020685). 13 paratypes with same data as holotype, 7 paratypes, TANZANIA: Ruvuma Region, Namtumbo District, Mkuju River, 831m, 10.08380S, 36.57267E ± 100m, 2-4.xii.2011, MKU2011-5.1 (P Hawkes, J Fisher) (AFRC, CASC, MCZC, NMKE, SAMC, USNM).

Worker diagnosis.

Scapes with abundant erect macrosetae.

Species description.

WORKER. Measurements in millimeters (n=18): TL: 2.6-3.2; HW: 0.50-0.59; HL: 0.68-0.77; EL: 0.19-0.23; SL: 1.07-1.24; PW: 0.41-0.5; WL: 0.94-1.20; PrFL: 0.78-0.91; GL: 0.92-1.30.

Indices: CI: 71-79; REL2: 37-44; SI: 198-220.

Overall coloration dark brown with lighter mandibles, antennae (especially funicular segments towards tips) and legs (especially trochanters of mid and hind legs, and distal portions of tibiae and tarsi); cuticle smooth, shining, and with very faint shagreenate sculpture, which is more obvious on head and gaster. Head narrow, distinctly longer than broad, with abundant dark, erect macrosetae; anterior clypeal margin with a shallow medial indentation; scapes with a dense layer of pubescence and scattered erect macrosetae (SSC = 17-29); eyes large and convex, extending beyond head lateral margin in full frontal view; posterior head margin with rounded posterolateral corners; three distinct ocelli present. Mesosoma with scattered dark erect macrosetae (PSC = 2-5; MSC = 2-3); in profile pronotum and mesonotum shallowly convex dorsally, presenting a uniform overall curvature through their junction; metanotal area distinct, about 1/3 the length of the mesonotum; dorsal face of propodeum rounded, with short declivitious face; anterior portion of dorsal face with thin layer of pubescence. Gaster with abundant erect dark macrosetae.

Etymology.

The specific epithet is derived from the ancient Arabic name for the stretch of East African coast that encompasses parts of modern day Kenya, Mozambique, and Tanzania.

Non-type specimens examined.

ANGOLA: Huambo, Mont. Moko, 1725 m, 12°27.20'S, 15°07.45'E, 7.vi.2007, miombo woodland (BL Fisher) (CASENT0128086); MOZAMBIQUE: Sofala Prov., Gorongosa N.P., Ravine (18.63407S, 34.80689E), 172 m, 12.vi.2012 (P Naskrecki); Sofala Prov., Gorongosa N.P., Gorongosa Mountain, road to waterfall (18.49764S, 34.04975E), 800 m, 19.vi.2012 (GD Alpert).

Natural history and distribution.

Very little is known about the natural history of Paratrechina zanjensis ; the 23 specimens collected in the Mkuju River region of the Selous Game Reserve in Tanzania were all found in 48-hour pitfall trap samples (present in 8 of a total of 60 samples from two sites separated by about 1.3 km) while none were found in the 40 Winkler-extracted leaf litter samples collected during daytime along the same transects. The two Tanzanian sites in which Paratrechina zanjensis were found were representative of mature dry miombo woodland, while they appeared to be absent from both dry and moist closed canopy forest sites nearby. The Angola and Mozambique specimens were also collected in miombo woodlands; this, in combination with the absence of Paratrechina zanjensis from 15 forest sites surveyed by one of us (PH) in the Eastern Arc Mountains and Coastal Forests of Tanzania, suggests that the species prefers open woodland rather than forest habitats.

Figures

Figures 1 - 9. Paratrechina workers in various views (left to right: full frontal, lateral and dorsal views for figs 1 - 6): 1 - 3 Paratrechina longicornis (CASENT 0250003) 4 - 6 Paratrechina zanjensis holotype (SAM-HYM-C 020685) 7 Paratrechina longicornis scape (CASENT 0250003) 8 Paratrechina zanjensis holotype scape (SAM-HYM-C 020685) 9 Paratrechina zanjensis paratype mandible (CASENT 0250002).