Cataulacus fricatidorsus

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Cataulacus fricatidorsus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. fricatidorsus
Binomial name
Cataulacus fricatidorsus
Santschi, 1914

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Specimen Labels

Nothing is known about the biology of Cataulacus fricatidorsus.

Identification

A member of the intrudens group. Separable from Cataulacus wissmannii by details of structure and sculpturation, fricatidorsus may be distinguished from its immediate relatives by the form of margination and denticulation of the pronotum. When experience identifying the species of this group has been acquired it is apparent that in the present species the gaster tends to be proportionally shorter and broader than in related forms; also the tergite and sternite of the first segment tend to be strongly convex, giving the gaster a markedly short and stocky aspect. (Bolton 1974)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: South Africa (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.

  • fricatidorsus. Cataulacus otii st. fricatidorsus Santschi, 1914e: 26 (w.) SOUTH AFRICA. Raised to species: Bolton, 1974a: 42.

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

Description

Worker

Bolton (1974) - TL 3.5 – 3.8, HL 0.92 – 0.96, HW 0.98 – 1.04, CI 106 - 108, EL 0.40, OI 38-41, IOD 0.74 – 0.80, SL 0.48 – 0.50, SI 48 - 50, PW 0.82 – 0.86, AL 0.98 – 1.06, MTL ca 0.50 (2 measured).

Occipital crest absent, the vertex curving into the occiput through an obtuse angle. Occipital corners dentate and with a denticle on the occipital margin close to the corner tooth. Sides of head behind eyes denticulate; the preocular tooth usually reduced and rounded. Pronotum strongly marginate, the marginations expanded laterally so that they distinctly overhang the sides of the segment. Margination equipped with a number of irregular, rounded, tuberculiform denticles, some of which appear to be composed of two or more denticles fused together. Alitrunk strongly narrowed behind the pronotum. Mesonotum marginate but very weakly so, with one or two denticles. Propodeum with one or two lateral denticles and armed with a pair of short, acute spines. Dorsal alitrunk without any trace of sutures. Sides of first gastral tergite not marginate.

Dorsum of head finely reticulate-rugose with reticulate-punctate interspaces. Dorsal alitrunk similarly sculptured but the rugulation extremely fine except on the propodeum, where it is coarser than at any other place on the body. Dorsal surfaces of petiole and postpetiole longitudinally rugose. First gastral tergite strongly reticulate-punctate, without rugulae except at the base where a few longitudinal rugulae occur.

All dorsal surfaces of head and body with erect, stout, short hairs. In profile the hairs on the first gastral tergite are seen to be much denser basally and apically than in the centre of the sclerite.

Type Material

Bolton (1974) - Syntype workers, SOUTH AFRICA: Xatal, Zulu land, Dukudu, 27.vii.1905 (I. Triigardh) (NM, Basle) [examined].

References