Polyrhachis planoculata

The types were collected in a forest clearing.

Identification
A member of the Polyrhachis continua species group in the subgenus Myrma

Polyrhachis planoculata is the only known species of this group with the eyes not reaching the lateral cephalic outline in full face view. The flatness of the eyes is particularly evident when the head is viewed from behind. (Kohout 2013)

Distribution based on Regional Taxon Lists
Indo-Australian Region: New Guinea.

Castes
Sexuals and immature stages unknown.

Nomenclature

 *  planoculata. Polyrhachis planoculata Kohout, 2013: 32, figs. 26, 29-30 (w.) PAPUA NEW GUINEA.

Worker
Dimensions: TL c. 11.14; HL 2.81; HW 2.09; CI 74; SL 3.78; SI 181; PW 1.81; MTL 3.93 (1 measured).

Anterior clypeal margin arcuate, medially obtusely truncate. Clypeus with blunt, poorly indicated median carina; clypeus virtually straight in profile, posteriorly rounding into well impressed basal margin. Frontal triangle distinct. Frontal carinae with highly raised, laminate margins; central area narrow with rather short, but distinct, frontal furrow. Sides of head in front of eyes virtually straight, weakly converging anteriorly; behind eyes, sides produced into blunt carina extending towards occipital corners. Eyes rather flat, notably when viewed from behind, in full face view not reaching lateral cephalic outline. Ocelli lacking. Pronotal dorsum armed with only moderately long, anterolaterally directed, acute spines; lateral margins behind bases of spines rather flat, only weakly converging towards promesonotal suture. Mesonotal dorsum transverse with almost vertically raised anterior corners of lateral margins; metanotal groove flat. Propodeal dorsum with lateral margins only weakly raised anteriorly, converging posteriorly and terminating in blunt tuberculae; dorsum descending into declivity in rather smooth, evenly rounded curve. Petiole scale-like, dorsal margin armed with two slender, somewhat posteriorly curved, weakly divergent, acute spines with inner margins forming ‘U’-shaped petiolar dorsum; lateral margins of petiole below base of each spine with small, acute tooth. Anterior face of first gastral segment flat, with anterodorsal margin widely rounding onto dorsum.

Mandibles distinctly, longitudinally striate. Clypeus and front of head reticulate-punctate with pattern on sides and vertex somewhat longitudinally directed. Dorsum of mesosoma distinctly, mostly longitudinally reticulate-punctate; sides of mesosoma finely wrinkled; propodeal declivity and petiole, including spines, finely reticulate. Gaster finely shagreened.

Mandibular masticatory borders and outer margins with numerous, semierect, relatively long, golden hairs. Anterior clypeal margin with several long, anteriorly directed setae medially and fringe of shorter setae laterally. Numerous short to medium length, semierect hairs on clypeus, along frontal carinae and vertex; many shorter hairs fringing lateral cephalic outline in full face view. Antennal scapes with several, semierect, rather short hairs along leading edge. Dorsa of pronotum and mesonotum with very few, relatively short, semierect hairs; no hairs on propodeal dorsum and petiole. Several short, semierect hairs along ventral surfaces of femora and on tibiae. Petiole with numerous shorter hairs along lateral margins, including inner margins of spines. Gaster with numerous short or medium length, posteriorly inclined hairs, distinctly increasing in length towards gastral apex and over venter. Closely appressed, very short, silvery white or greyish pubescence variously over most body surfaces, with somewhat reddish tint on dorsum of gaster.

Colour. Black; mandibular masticatory borders lined reddish brown; antennae with funicular segments progressively lighter, yellowish brown towards apices. Legs dark reddish brown, tarsi a shade darker. Gastral venter and apex reddish brown.

Etymology
Name derived from the combination of Latin words planus, meaning flat, and oculus, meaning eye, for its rather peculiar flat eyes.

References based on Global Ant Biodiversity Informatics

 * Kohout R. J. 2013. A review of the Polyrhachis continua species-group of the subgenus Myrma Billberg (Hymenoptera: Formicidae: Formicinae) with keys and descriptions of new species. Australian Entomologist 40(1): 13-46.