Ponera alpha

Identification
Taylor (1967) - A New Guinean species not referable to any recognized species group. The workers are distinguished by the following characters:

1. Size exceptionally large; head width 0.76-0.85 mm. The next largest species of Ponera has a maximum HW of 0.73 mm.

2. Head broad (cephalic index 88-93), with distinct median clypeal tooth, and relatively small eyes with 6 or 7 very indistinct facets. The antennal scapes exceed the median occipital border by 1-1.5 X their maximum thickness and no antennal club is differentiated.

3. Petiolar node exceptionally broad- petiolar node index 92-98. This index does not exceed 90 in any other species.

Females of P. alpha are likewise characterized by large size, with very broad head and petiolar node.

Distribution
This taxon was described from New Guinea.

Nomenclature

 *  alpha. Ponera alpha Taylor, 1967a: 38, figs. 23, 24 (w.q.l.) NEW GUINEA.

Worker
Holotype. HL 0.94 mm; HW 0.83 mm; SL 0.77 mm; CI 88; SI 93; PW 0.66 mm; PNL 0.38 mm; PH 0.70 mm; DPW 0.64 mm; PNI 97. Mandibles with 3 well developed teeth occupying slightly less than apical 1 /2 of masticatory border; basal 1/2 with 6 small, regular denticles. General form of head as in fig. 23; sides moderately convex, occipital border feebly concave. Median clypeal border with a small, acute, anteriorly directed tooth, about 0.02-0.03 mm long. Eyes small, strongly convex, maximum diameter ca 0.04 mm; each with about 6 or 7 minute, indistinct facets. Anterior point of eye situated about 0.90 X distance from lateral occipital border to midpoint of anterior genal border. Scapes relatively very long, exceeding median occipital border by almost 1.5 X their maximum thickness. No distinct antennal club differentiated, antennomeres increasing gradually in length and breadth towards apex; terminal segment slightly longer than 2 preceding together.

Mesosoma as in fig. 24. Inferior pronotal angles obtusely pointed. Mesometanotal and lateral mesonotal sutures distinctly incised. Posterolateral propodeal margins forming angles of about 70°, viewed from above. Sides of propodeum, from above, fairly strongly concave; declivity moderately so. Petiolar node very thick and wide; contained by 2 strongly arched faces: a vertical anterolateral one, and a transverse posterodorsal one. These 2 faces separated by a distinct angled edge. Viewed from above the node forms an almost perfect half-circle, the posterior border almost straight. Subpetiolar process relatively low, fenestra small, circular; posterolateral teeth small, moderately divergent.

Mandibles smooth and shining, with a few scattered punctures. Clypeus irregularly shagreened. Frons opaque, with a close cover of shallow, irregular foveolate punctures, about 0.01 mm in diameter; so closely spaced that inter-punctural areas form a moderately fine raised reticulum. Scapes closely and coarsely punctate. Pronotum moderately shining, finely and shallowly transversely rugulose; the rugulae almost effaced, mixed with fine punctures. Mesonotum markedly more opaque than remaining mesosomal dorsum, coarsely and closely punctate, somewhat like frons, but with a longitudinal trend to interpunctural reticulum. Mesepisternal surface resembling pronotum, but rugulae more clearly marked and irregularly broken, not mixed with punctae, sculptural trend longitudinal. Similar sculpturing extends back over metepisternal area, below and in front of propodeal spiracle. Dorsum of propodeum moderately shining, with scattered punctures, sides smooth and very shiny. Declivitous face of propodeum, and posterodorsal face of node strongly shining, with a very fine, superficial scale-like microsculpture, visible in reflected light. Trend of this sculpturing transverse on propodeum, longitudinal on node. Anteroventral face of node shining, with scattered fine puncturation. Gaster similarly sculptured; a narrow strip on posterior margin of 1st gastric tergite finely shagreened.

Moderately long erect yellowish hairs plentiful on mandibles, clypeus, frontal lobes, scapes, entire dorsal surface of mesosoma, apex and sub-petiolar process of node, and entire gaster, where they are especially abundant. Pubescence almost everywhere abundant, fine and adpressed, longest in pilose areas, sparse on sides of mesosoma. Entire body very dark brown, almost black ; apices of frontal lobes, subpetiolar process and tip of gaster infuscated. Fore-coxae dark brown, remainder of legs, mandibles and antennae dull reddish brown.

Paratypes. 31 paratype workers collected with the holotype have the following dimensions: HL 0.85-0.94 mm; HW 0.76-0.85 mm; SL 0.70-0.77 mm; CI 86-93; SI 85-95; PW 0.57-0.68 mm; PNL 0.32-0.39 mm; PH 0.59-0.70 mm; DPW 0.54-0.65 mm; PNI 92-98. The relative proportions of the several dimensions vary in a manner similar to that of members of the Ponera coarctata group. Pronotum width and petiole height approximately isometric, relative to head width. Petiolar node width positively allometric (k = ca 0.85), while head length and scape length are both negatively allometric (k between 1.3 and 1.4). Size of eyes may range down to slightly less than 0.03 mm maximum diameter, and posterior mandibular denticles may number 6 to 8. Faceting of eyes very indistinct in this species, and a facet count is very difficult. Under low magnifications (less than 100 X) the eyes may appear as large, rather irregularly molded single facets.

Palpal formula (3 paratypes dissected): Maxillary 2 : Labial 2.

The mesosomas of many paratypes have partially collapsed in preservation, so that the concavity of the sides of the propodeum is exaggerated, and the pronotum, viewed from above, appears to have the inferior angles turned outwards.

Queens
Paratype. 3 dealates collected with the holotype have the following dimensions and indices: HL 0.93-0.96 mm; HW 0.85-0.87 mm; SL 0.77-0.78 mm; CI 90-91; SI 90-91; PW 0.72-0.75mm; PNL 0.35-0.36 mm; PH (1 measurement) 0.70 mm; DPW 0.67-0.70 mm; PNI 92-97. Maximum diameter of eye 0.17-0.18 mm; ocular index 20-21. Palpal formula (dissected); Maxillary 2: Labial 2. General form of mandibles, head, clypeus, and antennae as in worker. Anterior border of eyes situated about 0.40 x their length from lateral genal border, ocelli well developed. Mesosomal structure complete. Mayrian furrows absent, parapsidal lines distinct. Scrobal suture feebly marked. Petiolar node slightly thinner in side view than in worker ; forming slightly less than a half-circle in dorsal view.

Sculpture generally as in worker. Puncturation of head slightly finer, the overall effect more shagreened. Scutellum coarsely punctate ; metanotum smooth and shining. Entire sides and dorsum of propodeum finely longitudinally rugulose. Rugulae somewhat effaced in center of area above propodeal spiracle, the surface here moderately shining. Scalelike microsculpture on posterior faces of propodeum and node, more distinct than in worker, especially on node.

Color, pilosity, and pubescence as in worker.

Immature Forms
The larva has 6 pairs of glutinous tubercles on the abdominal dorsum, as do all other known Indo-Australian Ponera species. The pupae are not known.

Type Material
The holotype 1 queen paratype, and most paratype workers in collection (Type No. 30918). Additional paratypes in the following collections:, (including queen), , , (including queen), Emery Coli. , Forel Coll. ,, , and Yasumatsu Coll.

NE NEW GUINEA : Kunai Creek, l300 m, SW side of Bulolo River valley, near Wau. The holotype was collected from a leafmold berlesate taken in a disturbed fragment of midmountain rain forest in a dark damp roadside gorge, VI.1962 (RWT acc. 1966). Known only from the type locality (see fig. 36).

Additional paratype material. A small colony fragment of alpha was collected under bark on a fairly sound rotting branch immediately adjacent to the spot where leafmold had been previously collected (RWT acc. 1925). This probably represented the remains of the holotype colony; it included 4 workers, 3 dealate queens, about 10 larvae, of at least 4 instars, and a few eggs. The worker and queen measurements fall within the ranges of the paratype series discussed above.