Ponera petila

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Ponera petila
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Ponera
Species: P. petila
Binomial name
Ponera petila
Wilson, 1957

Ponera petila casent0059796 p 1 high.jpg

Ponera petila casent0059796 d 1 high.jpg

Specimen Labels

The single worker (holotype) was collected as a stray in the superficial layers of soil beneath a rotting log on the ground in primary lowland rainforest.

Identification

Taylor (1967) - The species group characters (4-segmented antennal club, absence of an incised mesmetanotal suture), and the small size, allow preliminary diagnosis. Petila may be separated from Ponera szaboi and Ponera szentivanyi by the following characters: From the probably sympatric szaboi, by slightly larger size (HW 0.32 mm, DPW 0.18 mm, opposed to 0.30-0.31 mm, and 0.15 mm respectively in szaboi). Proportionately longer scapes (SI 88; in szaboi 78-83), and broader petiolar node (PNI 72 against 65 in szaboi). Sculpturation of petila is considerably less intense than that of szaboi (compare the description below and for szaboi).

2. From szentivanyi, by smaller size (HW 0.34 mm in szentivanyi), broader head (CI 78, opposed to 75 in szentivanyi), and other dimensional differences (e.g., SI 88 in petila, 94 in szentivanyi, etc.). Sculpturation of the head and mesosoma of szentivanyi is about intermediate between that described for petila and that of szaboi discussed below.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

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

Check distribution from AntMaps.

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Ponera petila 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.

  • petila. Ponera petila Wilson, 1957b: 368, fig. 2 (w.) NEW GUINEA. See also: Taylor, 1967a: 102.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Wilson 1957 fig. 2

Holotype. HW 0.32 mm, HL 0.41 mm, SL 0.28 mm, CI 78, SI 88, PW 0.25 mm, petiolar height 0.25 mm, petiolar node length 0.13 mm, dorsal petiole width 0.18 mm. Very similar to Ponera szentivanyi, differing slightly in body and appendage proportions as given in the measurements cited above, and in the much feebler body sculpturing, which can be described as follows. Sides of head densely but shallowly punctate, and feebly shining. Entire dorsal and lateral surfaces of the alitrunk with puncturation or shagreening of variable density but everywhere shallow and feeble, so that the surface is feebly to strongly shining. The gastric tergites are also more feebly sculptured than in szentivanyi and their surfaces overall feebly shining.

Taylor (1967) - Wilson’s description did not mention lack of an incised mesometanotal suture in the workers, or that the palpal formula appears to be Maxillary 2: Labial 2 (the mouthparts are only partially exposed; so a positive count is impossible).

Sculptural details required for diagnosis are: head moderately shining, with small point punctures separated by distances about equal to their maximum diameter. Pronotal dorsum fairly strongly shining, with scattered minute punctures; mesonotum almost imperceptibly more closely punctate. Lateral surfaces of mesosoma feebly shagreened to smooth and shining.

Wilson’s dimensions of the holotype are: HW 0.32 mm; HL 0.41 mm; SL 0.28 mm; CI 78; SI 88; PW 0.25 mm; PNL 0.13 mm; PH 0.25 mm; DPW 0.18 mm; PNU 72.

Type Material

N-E. NEW GUINEA: lower Busu River, near Lae; May 10, 1955; a single worker (Wilson, acc. no. 999). {Museum of Comparative Zoology

References

  • Taylor, R. W. 1967a. A monographic revision of the ant genus Ponera Latreille (Hymenoptera: Formicidae). Pac. Insects Monogr. 13: 1-112 (page 102, see also)
  • Wilson, E. O. 1957b. The tenuis and selenophora groups of the ant genus Ponera (Hymenoptera: Formicidae). Bull. Mus. Comp. Zool. 116: 355-386 (page 368, fig. 2 worker described)