Polyrhachis emeryana

Nothing is known about the biology of Polyrhachis emeryana.

Identification
Polyrhachis emeryana is very similar to Polyrhachis expressa from Cape York Peninsula. Both species have widely rounded pronotal shoulders, a propodeum armed with spines and distinctly elongated lateral petiolar spines. However, P. expressa differs by its ﬁner sculpturation, notably on the dorsum of the head and mesosoma, and its less convex pronotal dorsum. The propodeal spines in P. expressa are quite long, columnar and bluntly terminated, while in P. emeryana they are short, triangular and acute. Also, the appressed pubescence in P. expressa is extremely short and inconspicuous, while it is distinctly longer and more prominent in P. emeryana. (Kohout 2006)

Distribution
Polyrhachis emeryana appears to be rare and restricted to the Solomons.

This taxon was described from Solomon Is.

Abundance
Rare.

Nomenclature
From Kohout (2006): In lieu of the apparently misplaced holotype, my concept of the species is based on a voucher specimen evidently compared with the holotype by Than (1978), and a few additional specimens collected by P. Greenslade at Mt Austen (Guadalcanal, Solomon Is).

Worker
Length 5 mm.

Head a little broader than long, broadly rounded behind and rather strongly narrowed in front. Clypeus only moderately convex, shallowly concave at middle of anterior border. Frontal carinae little divergent, extending to opposite middle of eyes, in profile elevated and evenly rounded in front. Antennal scapes surpassing occipital corners by about five eighths of their length. Pronotum broader than long. strongly convex above. Mesoepinotum little convex, the suture indicated by a very shallow and indistinct impression; subangulate between base and declivity. Epinotal spines nearly straight, a little shorter than their distance apart at base. Petiolar node subtriangular in profile, the dorsal edge margined and bearing four spines, the inner pair of which are triangular, as broad basally as long, and the outer elongate-triangular, acute apically and four times as long as the inner pair.

Moderately shining. Finely coriaceous and with minute punctation.

Very fine and short recumbent pubescence thinly distributed on head, body, and appendages.

Color black.

Type Material
The single type, a holotype worker, cannot be found - as reported by Kohout (2006).

Type Locality Information
SOLOMON IS, Malaita, Auki, col. W.M. Mann.

Additional References
Kohout, R. J. 2006. Review of Polyrhachis (Cyrtomyrma) Forel (Hymenoptera: Formicidae: Formicinae) of Australia, Borneo, New Guinea and the Solomon Islands with descriptions of new species. Memoirs of the Queensland Museum. 52:87-146.

Mann, W.M. 1919. The ants of the British Solomon Islands. Bulletin of the Museum of Comparative Zoology at Harvard College 63: 273-391.