Anochetus modicus, Brown, WL Jr.,, 1978

Brown, WL Jr.,, 1978, Contributions toward a reclassification of the Formicidae. Part VI. Ponerinae, tribe Ponerini, subtribe Odontomachiti. Section B. Genus Anochetus and bibliography., Studia Entomologica 20, pp. 549-638 : 582-586

[12] Anochetus modicus new species

Worker, holotype: TL 5.9, HL 1.45, HW 1.25, ML 0.84, WL 1.90, scape L 1.17, eye L 0.21 mm; Cl 86, MI 58.

Color rich, bright, brownish-red; corners of head, mandibles, antennae, legs, petiole and gastric apex lighter, more yellowish. A member of the A. risii group in habitus, mandibular form and armament, and body sculpture, but differing from risii , apart from smaller size and darker color, in the relatively shorter mandibles, scapes and eyes, as well as the following:

1. Scapes surpass posterior margins of «occipital» lobes by an amount less than the length of the first funicular segment.

2. Mesonotal disc reduced to a mere smooth, transversely straplike, raised strip, 4 times or more wider than long, limiting the strong longitudinal costulae of the metanotal saddle anteriorly.

3. Petiolar node smooth, moderately stout, almost perfectly erect, narrowly rounded at apex, but more broadly so than in risii , and not nippled; as seen in side view outline, both anterior and posterior slopes gently convex; base of petiole horizontally costulate, and with a brief anterior peduncle.

Body shining. Frontal striation weak, extending only a short way beyond frontal carinae caudad, not fanning out widely, leaving most of central vertex smooth and shining. Pronotum smooth and shining, the only distinct sculpture, aside from occasional faint traces of lateral striae, and some piligerous punctures, is the usual transverse striation of cervix, becoming coarser, more costulate, on base of anterior slope of pronotal disc. Meso- and metapleura smooth and shining, the former with distinct transverse suture. Propodeal dorsum transversely costulate, the costulae irregular and about 30 in number, with 4-5 more on declivity. Gaster smooth and shining, narrowed behind basal segment, but not noticeably constricted.

Long, fine, erect and inclined hairs fairly numerous and generally distributed over dorsal surfaces, undersides of head and gaster, anterior side of front coxae, and scapes and legs; up to 0.25 mm long on pronotum and gastric dorsum, but mostly not much over 0.1 mm elsewhere. Pubescence fine, mostly restricted to appendages.

Worker variation, paratypes: Of the 9 workers available, 5, including the holotype, are from Moaratoa 1., Borneo; 3 are from Tjibodas, Java; and 1 is from the Cuernos Mts., Negros I., Philippines. The combined measurements and indices for these are: TL 4.8-5.9, HL 1.21-1.45, HW 1.06-1.29, ML 0.71- 0.87, WL 1.50-1.80, scape L 1.01-1.21, eye L 0.16-0.21 mm; Cl 84-90, MI 58-62. The Moaratoa workers average larger (TL 5.7-5.9, HL 1.40-1.45, HW 1.22-1.24 mm; Cl 86-90, MI 58), but have slightly shorter trunks (WL 1.73- 1.74) than do the Javanese workers (WL 1.77-1.80), even though in other dimensions the latter are smaller: TL 5.5-5.7, HL 1.37-1.40, HW 1.15-1.18 mm; Cl 84-86, MI 58-62.

The single Philippine worker is small (TL 4.8, HL 1.21, HW 1.06, WL 1.50 mm; Cl 88, MI 59) and pale brownish-red in color, with the head slightly darker. Its petiolar node is a little more slender in side view than in the other 2 series.

While the Moaratoa series has fairly regular transverse costulation of the propodeal dorsum, the Tjibodas sample has the propodeal dorsum covered with mainly disoriented rugulation, showing only weak and partial organization into transverse costulae.

Queen, paratypes: Two specimens, one a callow alate taken with the Moaratoa series, the other a dealate taken alone in the Cuernos Mts. of Negros I. at "4000 ft." (about 1220 m). Moaratoa I.: TL 6.9, HL 1.54, HW 1.40, ML 0.84, WL 2.00, scape L 1.17, eye L 0.32 mm; Cl 91, Ml 55. Cuernos Mts., Philippines: TL 5.9, HL 1.31, HW 1.22, ML 0.78, WL 1.88, scape L 1.10, eye L 0.29 mm; Cl 93, MI 60.

The Moaratoa queen is winged (forewing L about 4 mm) and dull, light reddish-brown in color (callow); the Philippine specimen is dealate and light brownish-yellow. Pronotum and mesonotum smooth and shining (faint traces of diagonal striation on side of pronotum in Moaratoa queen).

Male: single specimen mounted on same pin with worker from Cuernos Mts., Philippines: TL 4.4, HL 0.71, HW (including eyes) 0.92, ML (closed mandibles) 0.11, WL 1.62, forewing L 3.3 mm.

Color dark brown, gaster slightly paler, especially toward apex; antennae tan; legs, mouthparts and genital capsule sordid yellowish. Eyes taking up about 2/3 of sides of head. Lateral ocelli separated from eye by about 0.2 mm, and distant from anterior ocellus by about the diameter of the latter. Mandibles small, cuneiform as seen from above, acute, with conspicuous circular white basin at base.

Trunk robust, with convex dorsum and pleura; notauli obsolete, except for shallow longitudinal sulcus at rear of scutum; scutellum prominent, hemispherical; metanotum short, convex; propodeum convex, dorsum rounded into declivity; its spiracle very small, elliptical. Petiolar node subsquamiform; bluntly cuneiform as seen from side, with both anterior and posterior slopes slightly convex; sides convex, and apex rather broadly rounded as seen from in front. Gaster almost imperceptibly constricted after postpetiolar segment.

Terminalia unremarkable; pygidium folded, lightly sclerotized, and thus forming a barely acute beak; hypopygium narrow-linguiform, tapered to a truncate apex, its ventral surface convex. Parameres broadly subcuneiform in side view, with rounded apices; outer surfaces convex; bent slightly mesad just beyond their midlength as seen from dorsal view. Aedeagus thick; volsellae each with digitus and cuspis.

Tibial apices each with two spurs on middle and hind legs, of which the mesial spur of the hind leg is large and broadly pectinate. Hind wing with a well-developed anal lobe.

Entire body weakly to moderately shining, mostly smooth, with numerous fine piligerous punctures; additional fine shagreening around the periphery of the scutum, on anterolateral faces of propodeum, etc.

Virtually the entire, normally-exposed body surface and appendages covered with a short, dense, pubescence-like investiture, decumbent on extremities of appendages, but becoming erect or suberect on mesonotum and elsewhere. A few longer (but still short and fine) hairs on ocellar triangle (otherwise nearly bare, and very smooth), on anterior cheeks, on metanotum, on apex of petiolar node, and toward gastric apex.

Holotype worker (MCZ) and 4 paratype workers with one callow alate queen from "Moaratoa Isl[and], Borneo, [E.] Mjöberg». I have not been able to find a locality with this exact name on maps, charts, or gazetteers of the Borneo area. «Moara» in Malay means "mouth of river". The most similar island name I located is Maratua Island, for an atoll including a hill in the Celebes Sea southeast of Tarakan, off the east coast of Kalimantan Timur (Indonesian Borneo), but I am not at all certain whether this is the same as Mjöberg’s locality. Other paratypes (MCZ) are 3 workers from Tjibodas, Java, 1400 m (without collector’s name, but one specimen carrying the label "jumping ant"; also the single worker with one male from Chapman’s Camp, at about 1100 m in the Cuernos Mts., near Dumaguete, Negros Oriental, Philippines (J. W. Chapman). A single dealate queen also comes from "4000 ft." (about 1220 m) in the Cuernos Mts, (Chapman).

This species is similar to several species of the risii group; in fact, it is as nearly «average» a form for the group as one could hope to find. The very short, straplike, mesonotal disc is one distinctive feature; the mandibles are longer than in A. brevis , and its much more restricted frontal striation will distinguish modicus from A. strigatellus ; the smooth, shining pronotum separates it from the similar-sized A. incuttus. Probably A. modicus will be found eventually to be a widespread species in wet upland forests of the Sunda islands.

[13] Wilson (1959: 504-505, 508-509, fig. 2) outlined the largely complementary distributions of A. cato (New Guinea, Bismarck Archipelago, and all but the most easterly Solomons Islands) and the A. isolatus superspecies (peripheral to cato in the eastern Solomons - Santa Cruz Group, Waigeo I., Aru Is., and Yap I. in the Carolines). He also mentioned my interpretation of this central-peripheral pattern as one more case of a derived animal species replacing an older, related one from the middle of the range outward, a sequence that I feel is readily inferred from a number of distributional patterns seen in insects, birds and mammals of the Melanesian region. As so often happens, the accumulation of additional material in the cato-isolatus group complicates the picture as we saw it in 1959. (See figs. 38 and 55).

In the first place, we now know that isolatus occurs in the Philippines (several collections from the Cuernos Mts., near Dumaguete, Negros Oriental, by J. W. Chapman, and an alate queen from Mt. Banahao, S Luzon, collector unknown), on Guadalcanal I. in the Solomons (Honiara, Kukum, by P. J. M. Greenslade; Ilvbush, by Greenslade, workers and a dealate queen); and on the mainland of New Guinea.

Donisthorpe’s A. rossi of 1947 was synonymized by Wilson under A. cato , but Wilson neglected to determine the identity of Donisthorpe’s A. rossi of 1949 from Finschafen, except to say that the 1947 and 1949 forms represent different species. In fact, the 1949 A. rossi types are isolatus .

Members of the " isolatus superspecies" vary in color; the head, or head and trunk, usually are darker than, or concolorous with, the petiole and gaster. Wilson (1959: 503, couplet 7), described A. isotatus thus: "Head and alitrunk dark reddish brown, petiole and gaster dark yellowish brown...", while in the same couplet (p. 504), he characterized A. splendens as: "Head and alitrunk light yellowish brown, petiole and gaster light reddish brown". Since he did not see the type of splendens , the color had to be divined from Karawajew’s original description, which, however, reads: "Kopf und Thorax kastanien-braun... Beine, Petiolus, und Abdomen gelblich rostfarben". From this I judge that splertderts really differs little if at all from average specimens of isolatus from the Solomons, or from the types of Anochetus rossi Donisthorpe 1949 (not 1947) (Finschafen, New Guinea, E. S. Ross; worker specimen, CAS-San Francisco, No. 6977, is hereby designated as lectotype, while the queen with the same data and number is considered as paralectotype). This second A. rossi matches well with A. isolatus , ond I have accordingly placed it in synonymy. Donisthorpe’s description of the color of the worker as "reddish yellow" is misleading; I would call the lectotype brownish-red, with the gaster slightly lighter, more yellowish-red.

Karawajew’s figures and description of splendens are reasonably good, but reveal no characters that will separate this species from A. isolatus , so I consider these two to be synonyms as well.

Integrating these new facts and interpretations into our old pattern, we can see that the main trends are still the same. A. cato is the predominant, and in most localities, apparently, the only species of the pair occupying most of «central» Melanesia, while isolatus prevails in extralimital lands to the east and west. The two known surviving «species» of the isolatus superspecies are essentially color forms: seminiger , from Waigeo I., and splendidulus , from Yap. From our present information, we cannot tell objectively whether these two forms are separate from isolatus as species, or as mere geographical races. This is the circumstance that haunts all attempts to distinguish superspecies from «polytypic» species. No harm will be done if we continue to treat them arbitrarily as species.

It remains to point to the male of A. isolatus (figs. 60, 61) as having the most primitive terminalia thus far known in Anochetus . The pygidial spine is a particularly archaic character linking the genus to both Odontomachus and the sub tribe Poneriti of Ponerinae . Perhaps other Anochetus species ( gladiator ?) of the Indo-Australian area have males with even more primitive terminalia. A. filicornis , still unassociated with the female castes, is also pretty close to the archetypal pattern.