Comprehensive DescriptionRead full entry
Holotype worker: TL 3.4, HL 0.67, HW 0.50 (CI 75), ML 0.06, scape L 0.34, WL 0.82, petiolar node L 0.29, W 0.30, postpetiole L 0.40, W 0.43 mm.
Habitus of small S. steinheili HNS , or S. duchaussoyi HNS , and with the truncal dorsum almost perfectly flat and the color tawny, as in S. duchaussoyi HNS , but with antennae 12 - merous and sculpture more dense and opaque.
Head oblong, with parallel, weakly convex sides and transverse (almost imperceptibly concave) posterior margin as seen in full-face view. Posterior corners rather sharply rounded. No eyes or remnants of eyes visible at magnification of X 100. Frontal carinae short, close together, touching behind; anterior slope of clypeus between them with a minute tubercle or carina. Translucent apron of free clypeal margin much as in S. steinheili HNS , narrowly rounded. Fused posterior frontal carinae continued posteriad for a short way on anterior part of head as a fairly distinct carina.
Mandibles triangular, with basal border rounding into masticatory margin; the latter apparently edentate most of its length, but there may be a few minute denticles near the basal angle. Mandibular surfaces smooth with small, spaced punctures.
Trunk almost exactly twice as long as broad (excluding pronotal cervix, but including propodeal declivity), nearly parallel-sided, but slightly wider across the posterior half and very feebly constricted near midlength. Sutures obliterated; pronotal cervix separated from main part of pronotum by a shining, transverse, curved groove, but there is no distinct transverse pronotal margin. Propodeal declivity finely shagreened, subopaque, bounded by a weak margin on the sides and arching over the top.
Petiolar node subquadratic, with nearly straight anterior and posterior margins and gently convex lateral ones. Postpetiole trapezoidal, with straight anterior and almost straight (very feebly convex), posteriorly diverging sides. First 3 (principal) gastric segments wider than postpetiole and just about equal to one another in width (0.53 mm) and length; slightly depressed. Last visible tergal segment (pygidium) narrower, tapering caudad, but with a subtruncate apex, perhaps even a trifle emarginate in the middle; marginal spinules in 1 or 2 rows.
The sculpture of S. asper HNS is intermediate between those of S. steinheili HNS and s. caledonicus HNS , being more closed and opaque, i. e., with fewer and notably narrower smooth spaces between the foveolae than in steinheili HNS , but with at least a few narrow, smooth, shining interspaces on middle of the sides of head and sides of pronotum, and even a few very narrow ones on the truncal dorsum, yielding a sparkle here and there if looked for carefully. S. caledonicus HNS lacks these shining spaces, though the rims of the foveolae themselves reflect some small weak points of light in the New Caledonia species.
In S. asper HNS the petiole, postpetiole, and gastric dorsum are all densely punctate, and their surfaces are in general only moderately shining, the gaster more so than the nodes. Legs and scapes densely punctulate, opaque, femora weakly shining.
Pilosity short but abundant, tending to be appressed or decumbent over most of the body; a very few longer erect hairs, particularly near the apices of the gastric segments, may represent original standing pilosity, or may be the result of the brushing and ruffling needed to clean dirt particles from this old specimen. A few of these longer hairs on propodeum (perhaps ruffled erect), and a number at gastric apex, probably normally standing. Scapes and legs with appressed to decumbent pilosity.
Color uniform tawny yellow, the legs perhaps a bit lighter.
Queen (ergatoid): TL 3.9, HL 0.72, HW 0.54 (CI 75), ML 0.06, scape L 0.39, greatest diameter of compound eye 0.10, WL 0.94, petiolar node L 0.31, W 0.33, postpetiole L 0.40, W 0.48 mm.
Aside from its larger size, 3 distinct ocelli, and distinct, flat, subcircular compound eyes (with about 50, perhaps more, fine ommatidial facets), the ergatoid queen is little different from its worker. The sculpture is, if anything, still finer and more opaque, and the pilosity and color are much the same.
Male (postpetiole and gaster missing): HL 0.57, HW across and including eyes 0.64, ML 0.12, WL 1.17, forewing L 2.46 mm.
Translucent apron of clypeal margin sharply rounded, covering inner bases of closed mandibles, which are triangular; no space between mandibles and clypeus. Antennae 13 - merous; pedicel about as broad as long, succeeding (second funicular) segment smaller, also about as broad as long; remaining segments all longer than broad; apical segment twice as long as penultimate segment.
Notauli distinct, forming a complete Y. Scutellum rounded and prominent. Propodeal declivity with strong lateral and dorsal margins, forming an angle in side view. Petiolar node rounded above, slightly broader than long.
Head contiguously and rather coarsely punctate and opaque. Mandibles shining, with scattered, fine punctures. Trunk densely punctate dorsally, with weakly shining interspaces. Scutellum, metanotum, and propodeum contiguously punctate, with a few rugulae, opaque; propodeal declivity striate-reticulate, subopaque; sides of pronotum and mesopleura sparsely punctate on a smooth and shining surface. Petiolar node indistinctly punctate and shagreened, subopaque. Pilosity short, appressed to suberect, pubescence-like. Color castaneous brown, mandibles and legs dull yellow; antennae light brown.
The holotype worker, ergatoid queen, and male were originally found in MCZ miscellany, pointed together on a single pin labeled as from Halifax, N Queensland, Australia, June 1919, F. X. Williams. All are deposited in MCZ, and if additional material exists, I have not seen it. The real relationship of S. asper HNS will not be known until all of the Australian Sphinctomyrmex HNS species are better represented in collections and associated with the proper males. S. asper HNS is probably closest to the New Caledonian species, s. caledonicus HNS , but, in addition to the characters cited in the key, S. asper HNS is much lighter in color, is more slender, and has much straighter (less convex) sides of the postpetiole seen in dorsal view than does S. caledonicus HNS ; the latter species also has a distinct if fine transverse margin across the front of the pronotum.