Cataulacus pompom

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Cataulacus pompom
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. pompom
Binomial name
Cataulacus pompom
Snelling, R.R., 1979

Cataulacus pompom P casent0900255.jpg

Cataulacus pompom D casent0900255.jpg

Specimen Label

Nothing is known about the biology of Cataulacus pompom.

Identification

Cephalic and mesosomal sculpturation reduced; cephalic dorsum with abundant very short bizarre hairs. A member of the taprobanae group as evidenced by the reduced sculpturation, with the rugulae of the mesosomal dorsum principally longitudinal. The occipital crest is normal for the group, and is especially similar to that of such species as Cataulacus praetextus and Cataulacus reticulatus. It is immediately different from all taprobanae group species in the abundance of bizarre hairs on the cephalic and mesosomal dorsa. Hairs of this type appear to be of rare occurrence in the Indo-Australian-Oriental fauna although frequent in species of the Ethiopian Region. Somewhat similar, though less bizarre, hairs are seen in Cataulacus simoni and, to a lesser degree, Cataulacus granulatus. These are members of the granulatus group and differ from pompom in the nature of the cephalic and mesosomal sculpture. (Snelling 1979)

Regional Cataulacus Key

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Malaysia (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Much of the information concerning the biology of Cataulacus species is anecdotal and fragmentary. Arnold (1917) wrote a succinct general overview of Cataulacus biology that still remains quite informative. Arnold reports "all the species of this genus are tree-ants, usually forming medium sized nests in hollow twigs and stems, or more rarely, under the bark. They are timid and slow-moving insects, often feigning death or dropping rapidly to the ground when disturbed. As Bingham has remarked in connection with this genus (Fauna Brit. India, Formicidae), these ants have the habit of wandering over the trunks of trees and the leaves in what appears to be a very aimless and languid manner. I have occasionally seen them breaking open the earthen tunnels constructed by termites over the trunks of trees and attack the inmates."

Bolton (1974) expands upon this earlier account - "All known Cataulacus species are arboreal or subarboreal nesters and they predominantly forage on the trees and shrubs in which the nests are situated. Very few appear to come down to ground level but in West Africa the small species Cataulacus pygmaeus and Cataulacus brevisetosus may be found foraging in leaf litter or crossing the ground to ascend a tree other than the one in which the nest is situated. The nests themselves are usually constructed in small hollow twigs or stems by the smaller species and in rotten branches or rotted portions of the tree trunk by the larger species. This is rather a generalization as some small species are known which nest in and under rotten bark (e.g. Cataulacus vorticus) and undoubtedly some of the larger forms will eventually be found inhabiting relatively small cavities in plants.

Various species of the genus in Africa are known to inhabit a variety of galls, acacias and bushes as well as large trees. Numerous species have been found nesting in, and have therefore been often collected from, cocoa in Africa. Some of these species are Cataulacus guineensis, Cataulacus pygmaeus, Cataulacus mocquerysi, Cataulacus egenus, Cataulacus vorticus, Cataulacus brevisetosus, Cataulacus kohli and Cataulacus theobromicola. Feeding habits in the genus are mostly unknown but the present author has noted C. guineensis tending aphids and small coccids.

On the plants ants of the genus Cataulacus often occur together with Oecophylla or species of Crematogaster, and appear to be mostly tolerated (at least they are not evicted) by the majority of these forms. Their defence against attackers of these genera lies primarily in their armoured exterior, but their ultimate escape reaction is to curl up and release their grip on the plant, falling to the ground and thus making their escape. The decision to remain immobile and present an armoured surface or to drop from the plant appears to depend upon the size or persistence of the aggressor; larger attackers usually precipitate the latter reaction, but it has also been noted as a result of persistent and unwanted attention by a series of workers of a small Crematogaster species.

The majority of species are forest-dwelling forms, with relatively few adapted to savannah or veldt conditions. Those which do, however, occur in these zones tend to be very successful in their chosen habitat and often possess a wide distribution. A few species are apparently able to exist in any region of Africa providing the basic essentials of nesting-site and food supply are met with, but on the whole the fauna may be divided into forest and non-forest forms."

Some species have nests that can be protected by a single worker's head, as its shape matches the nest entrance and forms an effective plug.

It has more recently been discovered that some species of Cataulacus are efficient gliders (Cataulacus erinaceus, Cataulacus guineensis, Cataulacus mocquerysi and Cataulacus tardus). Workers exhibit directed movement while in freefall that allows them to glide back to regain a hold on the same tree trunk. (Yanoviak et al. 2005, 2007, 2008)

Castes

Nomenclature

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

  • pompom. Cataulacus pompom Snelling, R.R. 1979a: 8, figs. 19-26 (w.) WEST MALAYSIA.

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

Description

Worker

Holotype worker. TL 3.46; HL 0.83; HW 0.94; CI 112; EL 0.32; OI 34; IOD 0.72; SL 0.45; SI 48; PW 0.69; WL 0.96; MTL 0.37.

Occipital crest complete, the median portion raised into a low, projecting ridge in full-face view; with well-separated weak denticles. Side of head denticulate behind eyes, occipital corner with a low, broad, triangular tooth. Sides of propodeum with a narrow, rectangular expansion, marked at each end by a blunt denticle and with another, smaller, denticle near middle. Sides of mesonotum roughly triangular in dorsal view, with a deep V-shaped notch separating them from propodeum. Propodeum behind this notch with a short free anterior face; side marginate, continuous with side of spine, margin with two or three minute denticles. First gastric tergum marginate on anterior one-fourth, margin with several weak, oblique denticles.

Dorsal surface of head finely rugoreticulate, interspaces finely and densely reticulate-punctate. Dorsal surface of mesosoma similar, but with longitudinal rugulae stronger. Dorsal surfaces of petiole and postpetiole very densely reticulate-punctate, with a few short, obscure longitudinal rugulae. First gastric tergum finely and very densely reticulate-punctate, with numerous short, fine obscure rugulae, the majority of which are more or less longitudinal.

Dorsal surface of head with numerous very short, bizarre hairs (Fig. 24), but with a few longer, subspatulate hairs along inner eye margin. Dorsal surface of mesosoma with short, bizarre hairs along margins and with two transversely arcuate rows across anterior part of pronotum. Petiole and postpetiole each with a few similar hairs; first gastric tergum with a short, bizarre hair on each marginal denticle. Dorsal surfaces of meso- and metafemora and external surface of mesotibia with 1-4 such hairs.

Paratype workers. TL 2.87-3.44; HL 0.74-0.85; HW 0.83-0.94; CI 110-114; EL 0.28-0.32; OI 33-35; IOD 0.65-0.71; SL 0.40-0.44; SI 47-49; PW 0.60-0.69; WL 0.81-0.97; MTL 0.33-0.40 (9 measured).

Type Material

Holotype worker, MALAYA: Selangor, Gombak, 2 Oct. 1973 (B. Bolton), from topmost twigs of felled forest tree, in British Museum (Natural History). Paratype workers, 9, same data as holotype, in British Museum (Natural History) and Los Angeles County Museum of Natural History.

Etymology

The name proposed for this species is an arbitrary combination of letters and should be treated as a noun.

References

  • Snelling, R. R. 1979a. Three new species of the Palaeotropical arboreal ant genus Cataulacus (Hymenoptera: Formicidae). Contr. Sci. (Los Angel.) 315: 1-8 (page 8, figs. 19-26 worker described)