Sphinctomyrmex trux, Brown, W. L., 1975

Brown, W. L., 1975, Contributions toward a reclassification of the Formicidae. V. Ponerinae, tribes Platythyreini, Cerapachyini, Cylindromyrmecini, Acanthostichini, and Aenictogitini., Search: Agriculture; Cornell University Agricultural Experiment Station 15, pp. 1-115 : 77-78

[72] Sphinctomyrmex trux new species

(Figs. 2, 101, 102, 105 - 113)

Holotype worker: TL 4.7, HL 0.87, HW 0.76 (CI 87), ML 0.12, scape L 0.50, WL 1.16, petiolar node L 0.38, W 0.48, postpetiole L 0.50, W 0.64 mm.

Paratype workers (21): TL 4.4 - 5.2, HL 0.84 - 0.94, HW 0.74 - 0.84 (CI 87 - 89), ML 0.12 - 0.15, scape L 0.47 - 0.54, WL 1.12 - 1.26, petiolar node L 0.40 - 0.44, W 0.44 - 0.50, postpetiole L 0.53 - 0.58, W 0.61 - 0.68 mm.

The figures show body form, pilosity, and some details of sculpture well enough; only features not, or poorly, shown or those needing emphasis will be described here.

Head with posterior border straight, extremely feebly concave in the middle as seen in full-face view, sides convex; eyes represented by pigmented dots at middle of sides of head, each without a distinct ommatidial facet. Frontal carinae with lobes sharply raised, subcontiguously converging and truncate behind; median carina of anterior slope of clypeus indistinct and forming only a low tubercle in full-face view. Anterior translucent apron of clypeus with a strongly convex border.

Mandibles triangular, with basal border rounding gradually into masticatory border, the latter finely crenulate on basal half, edentate on apical half; apex acute; external Labrum with a narrow median cleft in from the free margin; extensor surface with a transverse carina near midlength, in the middle forming a low, blunt transverse tubercle, also a small tubercle at either side of the labral shield, and a bluntly rounded tubercle or process at each side of an extension of the flexor face. Maxillary palpi 3 - merous; first segment narrow; second segment long and broad, flattened, with a laterapical angle bearing 2 sensilla; apical segment small, its rounded apex bearing a single long sensillum. Labial palpi with a long, slender basal segment, subequal in length to the 2 shorter, broader distal segments taken together; apical and subapical sensilla 6 - 7.

Antennae with 12 distinct segments, all transverse except scape and apical segment, the last barely wider than preapical segment, and about 2 1 / 2 times as long.

Sculpture and pilosity well shown in figs. 105 - 107, 109 - 111, and the sculpture fairly well for the petiolar disc in 112, but even here not all of the punctures near the center of the disc appear in the photograph; punctures of petiolar node decidedly smaller and more numerous than on truncal dorsum. Postpetiole and gastric terga all densely sown with punctures similar in size to those of the petiole, but much more numerous and crowded, many contiguous or subcontiguous, but all these surfaces nevertheless rather strongly shining. Pilosity of postpetiole and gaster, as can be seen from figs. 108, 109, 112, and 113, copious, suberect, with a conspicuous pubescence of appressed to decumbent, fine, short hairs. Antennae and legs punctulate, weakly shining, with long, fine decumbent pubescence (some longer suberect hairs on scapes); posterior faces of femora smooth and shining with scattered piligerous punctulae. Declivity of propodeum shining, microreticulate, with scattered piligerous punctulae.

Color medium brownish red; legs and antennae a little lighter and more yellowish.

Queen unknown.

Holotype (MCZ) and 21 paratypes (ANIC — Canberra, BMNH-London, MCZ, MHN-Geneva) taken near Ravenshoe, on the Atherton Tableland, N Queensland, Australia at about 3000 ft. (900 + meters) in April 1932 by P. J. Darlington, Jr.

This species has been compared directly with the types of all the related forms in the European museums, and it seems to be distinct in its particular combination of size, head shape, sculpture, and pilosity. There is, of course, the possibility that geographical or intrapopulation variation in some or all of these characters may be much greater than the available samples indicate, in which case some of these 12 - segmented Australian Sphinctomyrmex may prove to be synonyms. I have seen males corresponding to at least 5 Australian Sphinctomyrmex species, however, and these are all quite distinct from one another. When we have reared colonies of this genus and get the males and queens in association with workers, the taxonomy will be more secure.

Meanwhile, the key to Sphinctomyrmex of the Indo-Australian region will help to distinguish this species.