Polyrhachis (Aulacomyrma) decora, Kohout, R. J., 2007

Kohout, R. J., 2007, Revision of the subgenus Aulacomyrma Emery of the genus Polyrhachis F. Smith, with descriptions of new species., Advances in ant systematics (Hymenoptera: Formicidae): Homage to E. O. Wilson - 50 years of contributions. (Memoirs of the American Entomological Institute 80), pp. 186-253 : 220-221

Polyrhachis (Aulacomyrma) decora , new species

Figures 57, 60, 63

TYPE MATERIAL

HOLOTYPE: INDONESIA, IRIAN JAYA ( New Guinea : Neth. on data label), Vogelkop , Fak Fak , S. coast of Bomberai Pen., 02 º 55 ’ S, 132 º 18 ’ E, 10 - 100 m, 3. vi. 1959, T. C. Maa (worker). PARATYPES: data as for holotype (3 workers) ; Vogelkop , Bomberi , Bomberai Pen. , 02 º 48 ’ S, 132 º 50 ’ E, 700 - 900 m, 6 . vi. 1959 , T. C. Maa (2 workers) ; ditto, 10. vi. 1959, J. L. Gressitt (worker). Type distribution: holotype and 2 paratypes in MCZC; 1 paratype each in ANIC, BMNH, CASC and QMBA .

WORKER

Dimensions: TL c. 5.19 - 5.74 (5.19); HL 1.31 - 1.37 (1.31); HW 1.09 - 1.15 (1.09); CI 81 - 84 (83); SL 1.37 - 1.47 (1.43); SI 126 - 131 (131); PW 0.90 - 0.94 (0.90); MTL 1.43 - 1.47 (1.43) (7 measured).

Clypeus with anterior margin arcuate, shallowly medially emarginate; in profile clypeus weakly convex with distinct notch anteriorly formed by furrow between clypeal striae; basal margin very weakly impressed. Frontal triangle indistinct. Frontal carinae very short, strongly raised with laminate lobes. Eyes very convex, protuberant, somewhat protracted posteriorly. Sides of head in front of eyes weakly converging anteriorly; strongly converging behind into laterally and posteriorly immarginate posterolateral corners; in lateral view relatively high vertex descends abruptly into narrow margin. Mesosomal dorsum laterally and posteriorly immaginate. Pronotal humeri armed with very strong, laterally and anteriorly directed spines with raised margins, dorsum of spines shallowly concave. Promesonotal suture distinct; metanotal groove lacking. Combined length of mesosomal and propodeal dorsa distinctly longer than pronotum. Propodeal dorsum descending uninterrupted into rather short propodeal declivity. Petiole scale-like with sharp dorsal margin terminating laterally in short, acute teeth. Base of first gastral segment anteriorly convex.

Mandibles finely longitudinally striate. Sculpture of head, mesosoma and petiole consisting of strongly raised, regularly spaced striae with deep interspaces resulting in a “ ploughed ” appearance; striae anteriorly converging on clypeus, U-shaped on apex of vertex, strongly curved medially from posterolateral corners towards central area between frontal carinae. Pronotal dorsum with inverse, open V-shaped striae, descending obliquely and uninterrupted onto sides. Mesonotal and propodeal dorsa with regular, U-shaped striae that are continued along sides and interrupted medially by smooth surface of declivity. Petiole with dorsally bowed striae on both faces. Gaster with distinctly finer striae, longitudinal on sides, less distinct and anteriorly converging on dorsum.

Off-white, erect, medium length hairs on dorsum of head and mesosoma, a few distinctly shorter hairs along dorsal margin of petiole. Hairs on gaster golden, somewhat longer, curved posteriorly on dorsum. Silvery, appressed pubescence virtually absent from head and mesosoma; small, thin patches on propodeal lobes, along declivity, coxae and subpetiolar process. Gaster with fairly dense, reddish-golden pubescence mostly restricted to dorsum of first segment.

Black with very smooth and glossy striae on head, mesosoma and petiole. Antennal scapes very dark, funiculi dark reddish brown with only apical funicular segment distinctly lighter. Legs dark reddish brown, except trochanters and femora, blending from light yellow over proximal halves to very dark brown at distal ends.

Sexuals and immature stages unknown.

ADDITIONAL MATERIAL EXAMINED

PAPUA NEW GUINEA: Huon Pen., Mongi Watershed, Wamuki, 800 m, 19 - 20. iv. 1955 (E. O. Wilson # 847 (w).

ETYMOLOGY

Named for its highly decorative sculpture pattern.

REMARKS

P. decora is rather similar to gressitti , kokoda and mamba which all have virtually identical sculpture of the mesosoma and a rather convex base of the first gastral segment. It differs from all of them in having a highly convex vertex, a feature notably distinct in lateral view. Additionally, decora differs from gressitti in having the mesosomal dorsum distinctly longer, from kokoda by the longitudinally striate first gastral segment and from mamba by the strongly convex, protuberant eyes.