Polyrhachis electra

Polyrhachis electra appears to be restricted to the Wet Tropics region of northern Queensland with all specimens having been collected at high altitude localities above 700 m in elevation. It is a ground-nesting species with entrances usually hidden under a rock.

Identification
A member of the penelope species-group in the Polyrhachis subgenus Hagiomyrma. Kohout (2013) - Polyrhachis electra is somewhat similar to Polyrhachis penelope, but differs in having the propodeal spiracles situated on laterally projecting tubercles. However, the spiracular tubercles are shorter and less conspicuous than those in Polyrhachis diversa and Polyrhachis tubifera. Polyrhachis electra differs from P. penelope in the shape of the petiolar spines which are longer and obliquely elevated in P. electra, and horizontal in P. penelope. In addition, the pubescence in P. electra is rather golden and abundant over all dorsal body surfaces, while it is much diluted and more silvery or pale golden in P. penelope.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Castes
Males present in QM spirit collection. Immature stages unknown.

Nomenclature

 *  electra. Polyrhachis (Hagiomyrma) electra Kohout, 2013: 537, figs. 7C-D (w.q.m.) AUSTRALIA.

Worker
(holotype cited first): TL c. 7.06, 6.45-7.51; HL 1.81, 1.56- 1.84; HW 1.50, 1.33-1.56; CI 83, 81-88; SL 2.00, 1.75-2.03; SI 133; 127-137; PW 1.37, 1.22-1.47; MW 0.87, 0.81-0.87; PMI 157, 157-178; MTL 2.18, 1.96-2.28 (23 measured).

Anterior clypeal margin with median, obtusely denticulate flange, laterally flanked by acute angles. Clypeus with distinct longitudinal carina, sinuate in profile; basal margin only weakly impressed. Frontal triangle indistinct. Frontal carinae sinuate with weakly raised margins anteriorly, flat posteriorly; central area wide with poorly indicated frontal furrow. Sides of head in front of eyes converging towards mandibular bases in straight line; behind eyes, sides rounding into weakly convex occipital margin. Eyes moderately convex, in full face view marginally breaking lateral cephalic outline. Ocelli lacking, positions of lateral ocelli indicated by weakly raised tubercles in cephalic sculpture. Pronotal dorsum wider than long with humeri distinctly rounded, dorsally shallowly concave; lateral margins converging posteriorly towards well impressed promesonotal suture. Mesonotal dorsum with margins converging posteriorly; metanotal groove weakly indicated laterally, indistinct medially. Propodeum with margins divergent, terminating in slender, subparallel spines with tips weakly turned outwards. Propodeal spiracles situated on laterally projecting tubercles. Petiole with anterior face straight, rounding dorsally into slender, divergent, elevated spines with tips curved upwards; dorsum descending posteriorly towards base in convex line. Anterior face of first gastral tergite widely rounding onto dosum.

Mandibles with numerous piliferous pits, closely and finely longitudinally striate at their bases, more polished towards masticatory borders. Head, mesosoma and petiole reticulate-punctate; spines sculptured at bases, smooth and polished towards tips. Gaster finely shagreened.

Mandibular masticatory borders with several, anteriorly inclined, golden hairs. Anterior clypeal margin with only a few anteriorly directed setae medially and fringe of shorter setae laterally. Several paired, relatively short hairs on clypeus, along frontal carinae and on vertex, no hairs exceeding lateral cephalic outline. Dorsum of mesosoma, coxae and venter of femora with several erect or suberect, short to medium length hairs. Gaster with a number of medium length hairs dorsally; hairs distinctly longer and more abundant around apex and venter of gaster. Rather abundant, closely appressed, golden pubescence on dorsum of head, mesosoma and petiole; more diluted, silvery pubescence on sides of body and base of petiole. Gaster dorsally with rich golden pubescence, completely hiding underlying sculpturation; pubescence distinctly less dense and silvery on gastral venter.

Black; mandibular teeth reddish-brown, apendages and apex of gaster dark to very dark reddish-brown.

Queen
TL c. 8.57-8.82; HL 1.90- 1.95; HW 1.62-1.65; CI 84-85; SL 2.00-2.03; SI 123-125; PW 1.84-1.93; MTL 2.31-2.37 (4 measured).

Apart from sexual characters very similar to worker except: pronotal humeri widely rounded. Mesoscutum marginally wider than long; median line bifurcate anteriorly; dorsum flat in profile with parapsides only weakly raised posteriorly. Mesoscutellum flat, not elevated above dorsal plane of mesosoma. Propodeal and petiolar spines similar to worker, but shorter. Sculpturation, pilosity, pubescence and colour identical to worker.

Type Material


Type deposition: Holotype, most paratype workers and paratype queens in, 3 paratype workers and paratype queen in ; 2 paratype workers each in , , , , , , and NMNH.

Etymology
Name derived from Electra, a daughter of Agamemnon and Clytemnestra, of Greek mythology.

Determination Clarifications
Polyrhachis electra was listed earlier by Kohout (2000: 199) as ‘Hagio 04’.

References based on Global Ant Biodiversity Informatics

 * Kohout R.J. 2013. Revision of Polyrhachis (Hagiomyrma) Wheeler, 1911 (Insecta: Hymenoptera: Formicidae: Formicinae). Memoirs of the Queensland Museum  Nature 56: 487577