Myopias julivora

Known to prey on millipedes. Colonies contain from 30 to 75 individuals and have a single queen.

Identification
Willey and Brown (1983) - Worker: Similar to Myopias tenuis, but larger (HW 0.80-1.01), with relatively longer mandibles and antennae, MI > 65, scapes overreaching posterior border of head (when held straight back, full face view) by about their own apical width to nearly twice their apical width; all antennomeres longer than broad. Shafts of mandibles approximately straight over middle half of their length.

The new species is close to the very variable M. tenuis. but seems constantly distinct from it, even where the two species occur in intimate sympatry, as they do in the Busu River tract. For relationship to M. media, see under that species below

Distribution based on Regional Taxon Lists
Indo-Australian Region: New Guinea.

Nomenclature

 *  julivora. Myopias julivora Willey & Brown, 1983: 254, figs. 5, 22 (w.q.) NEW GUINEA.

Worker
Holotype: TL 6.2, HL 1.04, HW 0.94 (CI 90), ML 0.73 (MI 70), MLO 1.01, SL 0.90 (SI 96), EL 0.09, WL 1.74, hind femur L 1.00, hind tibia L 0.94 mm.

Paratypes (n = 6 of 34 representing 7 colonies from 6 localities, including largest and smallest specimens): TL 5.8-6.7, HL 0.91-1.14, HW 0.81-1.01 (CI 88-90), ML 0.62-0.83 (MI 66-73), MLO 0.86-1.14, SL 0.86-1.09 (SI 96-108), EL 0.06-0.10, WL 1.66-1.93, hind femur L 0.89-1.15, hind tibia L 0.87-1.12 mm.

Description limited to details not covered in diagnosis and measurements. Median frontal sulcus extends approximately to middle of HL, followed posteriad after a gap by a shallow pit marking location in queen of anterior ocellus; this pit is usually absent in Myopias tenuis, but is occasionally faintly indicated there. Compound eye essentially reduced to a single convex lens, but at high magnifications, traces of an ommatidial grid can be made out; reduction approaches the state in M. tenuis, but does not go quite so far. Median clypeal lobe trapezoidal, widest near apex (CLL 0.12, CLW 0.16 mm), but by optical illusion may seem as long as or longer than wide; free corners rounded; anterior margin straight, convex, or even slightly sinuate. Basal oblique mandibular groove (strix) sublateral in origin, difficult to see in dorsal view, but distinct with its ventrolateral extension in side view. Submedian tooth situated in seventh tenth of the shaft length, counting from base. Basal angle obsolete.

The upturned tooth on each labrallobe and 3,3 pal pal segmentation formula are as in tenuis.

Trunk formed much as in M. tenuis; promesonotum subequal in length to propodeum; side view outline rather low and weakly convex, with a distinctly, but not deeply, impressed metanotal groove; propodeal dorsum only feebly convex, and sometimes very feebly impressed near mid length. Petiolar node slightly longer than broad, about as broad as long, or slightly broader than long, in different series (as in M. tenuis also), summit convex, slightly higher behind.

Gaster with first segment strongly rounded above, tergum rising caudad; segment II distinctly constricted in front at juncture with its acrotergite; about as high at maximum height as segment I, and slightly wider. As seen from above, anterior margin of segment I straight or feebly convex; shallowly concave in Vanimo worker (and queen). Sting long (extruded up to 0.6 mm), sharp, upcurved.

Sculpture prevailingly smooth and shining; punctures minute and widely spaced, more numerous and coarser on head, especially in Vanimo worker and queen, and on propodeum, but even here still obscure. Pilosity of uneven length, fine, tapered, erect to suberect hairs, mostly 0.05 to 0.30 mm long; pubescence decumbent to suberect, very dilute on anterior dorsum of head, but more abundant on antennae and legs, especially extremities.

Color averaging lighter than in fully pigmented M. tenuis workers, light to medium brownish red to dark brownish red, light orange brown in some workers, possibly callow. Appendages usually lighter, more yellowish, than basic body color.

Worker variation, as mostly discussed already above, involves mainly size-related features and shape of clypeal lobe, distinctness and density of the obscure puncturation, length and degree of apical taper of petiolar node, size and pigmentation of compound eyes, length of antennal scapes, and depth of body color.

Queen
Dealate (from type nest series, Wilson No. 905), TL 7.1, HL 1.10, HW 0.97 (CI 88), ML 0.74 (MI 67), MLO 1.02, SL 0.96 (SI 99), EL 0.26, WL 2.03 mm. Combined measurements for the largest queen specimen (above), another queen from the type locality, colony No. 1048, and a smaller queen from near Vanimo, are: TL 5.6-7.1, HL 0.93-1.10, HW 0.84-0.97 (CI 88-90), ML 0.63-0.76 (MI 67-72), MLO 0.87-1.03, SL 0.87-0.96 (SI 99-104), EL 0.22-0.26, WL 1.78-2.03 mm.

The queen differs from accompanying workers by the usual ponerine characters, and is also darker in color, prevailingly piceous, or even blackish in the Vanimo specimen. On trunk, centers of scutum and scutellum are infuscated, while marginal areas of these and other sclerites are lighter and more reddish. Appendages lighter, more yellowish.

Type Material
Described from material representing seven separate collections from six localities in Papua New Guinea. Holotype (MCZ) from Wilson's colony No. 905, lower Busu River, Huon Peninsula, Papua New Guinea, 3 May 1955, a nest in rain forest in a small Zoraptera stage rotten log, in a part of the log somewhat raised off the ground, containing one queen, about 30-40 workers, and brood of all stages, with pupae predominating. Abundant remains of millipedes were found in the brood chamber and galleries leading away. One fresh millipede corpse was among larvae; the prey all seemed to belong to one kind.

Another colony (Wilson No. 1048) also came from the lower Busu River tract, 15 May 1955, from cavities in an old, hard polypore fungus growing on a large Passalus-stage log, containing a queen and about 75 workers, plus abundant brood of all stages, without notable preponderance. Half of a freshly dead millipede was found with the brood; the midden remains were collected (but later lost with the nest residue in alcohol).

A worker and a dealate queen were found in lowland (40 m) rain forest next to the quarry at Km 2 on the Bewani Road, near Vanimo, West Sepik District, Papua New Guinea, 27 February 1981, leg. Brown (No. 81-48). The nest was in a small rotten stick lying on the ground, and contained larvae as well as the remains of small millipede prey. (Paratypes in MCZ, BMNH, ANIC, etc.)

In addition, single strays come from three widespread localities: Dobodura, March to July 1944, leg. P. J. Darlington, Jr.; lora Creek, 17 km. S. of Kokoda at 1400 m, leg. Ward (No. 1831) rotten log, montane rain forest; Baiyer River, Western Highlands, about 1200 m, 6 July 1974, leg. S. Peck, berlesate B-281. The last specimen is the largest one of the species seen; it is also the darkest in color, has somewhat coarser punctures than usual on the head, and has the longest scapes, so that it might be thought transitional to Myopias media, but the form of the mandibles and clypeal lobe is typical for julivora.

Etymology
The name of this species derives from the Latin julus, a millipede, and vorare, to devour.

References based on Global Ant Biodiversity Informatics

 * CSIRO Collection
 * Janda M., G. D. Alpert, M. L. Borowiec, E. P. Economo, P. Klimes, E. Sarnat, and S. O. Shattuck. 2011. Cheklist of ants described and recorded from New Guinea and associated islands. Available on http://www.newguineants.org/. Accessed on 24th Feb. 2011.
 * Willey R. B.; W. L., Jr Brown. 1983. New species of the ant genus Myopias (Hymenoptera: Formicidae: Ponerinae). Psyche (Cambridge) 90: 249-285.
 * Wilson Edward O. 1959. Adaptive Shift and Dispersal in a Tropical Ant Fauna. Evolution 13(1): 122-144