Ponera alpha

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Ponera alpha
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Ponera
Species: P. alpha
Binomial name
Ponera alpha
Taylor, 1967

Ponera alpha casent0172423 profile 1.jpg

Ponera alpha casent0172423 dorsal 1.jpg

Specimen labels

Only known from type material. The holotype was collected from a leaf mold berlesate taken in a disturbed fragment of midmountain rain forest in a dark damp roadside gorge.

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.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: New Guinea (type locality).

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Ponera alpha for further details

Biology

The general biology of species in the genus was summarized by Taylor (1967): Ponera are small ants that nest in rotting logs in forested areas or under stones in nonforested situations. In the tropical areas specimens are rarely encountered away from rain forest. In temperate areas, however, species may occur in relatively lightly forested areas. This appears to be the case with Ponera japonica, Ponera pennsylvanica and especially with Ponera coarctata. The Australian Ponera leae is essentially limited to rain forest in the northern parts of its range, but further south it may be found in dry, lightly forested areas.

Foraging is probably cryptobiotic, though some New Guinea species have been taken straying on the ground surface. Little information is available concerning feeding. However, most species are probably insectivorous. I have conducted feeding experiments with some of the New Guinea and Samoan species, including Ponera xenagos, Ponera elegantula, Ponera tenuis, Ponera incerta and Ponera woodwardi. These were unsuccessful with the larger species, except elegantula, which accepted moderately large (8-12 mm) campodeid and japygid Diplura. Tenuis and incerta accepted smaller (4-6 mm) campodeids, isotomid and sminthurid Collembola, and small newly hatched spiders (2 mm long). Negative feeding response was obtained with eggs and larvae of various ants, small crushed insects of various orders, and small myriapods. Stray workers were never observed carrying prey, and distinct middens of insect or other remains were not located near nests.

Colonies usually contain about 30 workers. Larvae and pupae are not segregated in most cases, but occasionally aggregations of pupae were observed. These may have included the total brood of the colonies involved. Larvae are attached to the floor or walls of the nest galleries by the glutinous abdominal tubercles described above, and the ants move them high up on the walls or ceilings of artificial nests, if they are flooded. Details of nuptial behavior of pennsylvanica were given by Wheeler (1900), and Haskins & Enzmann (1938). The flights appear to be of a pattern typical for ants, with the alates meeting in the air and mating there or on the ground. Colony foundation is non-claustral and independent in pennsylvanica (Kannowski 1959); judging from my observations this is typical for the genus.

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

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

Description

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.

Taylor 1967 Ponera fig 23-26

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

Ponera alpha casent0172423 label 1.jpg

The holotype 1 queen paratype, and most paratype workers in Museum of Comparative Zoology collection (Type No. 30918). Additional paratypes in the following collections: American Museum of Natural History, Bernice P. Bishop Museum (including queen), The Natural History Museum, California Academy of Sciences, Australian National Insect Collection(including queen), Emery Coli. Museo Civico di Storia Naturale, Genoa, Forel Coll. Musee d'Histoire Naturelle Genève, Musee National d'Histoire Naturelle, National Museum of Natural History, 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 leaf mold 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.

References

  • Taylor, R. W. 1967a. A monographic revision of the ant genus Ponera Latreille (Hymenoptera: Formicidae). Pac. Insects Monogr. 13: 1-112 (page 38, figs. 23, 24 worker, queen, larva described)