Cataulacus jacksoni

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Cataulacus jacksoni
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. jacksoni
Binomial name
Cataulacus jacksoni
Bolton, 1982

Cataulacus jacksoni P casent0900268.jpg

Cataulacus jacksoni D casent0900268.jpg

Specimen Label

Nothing is known about the biology of Cataulacus jacksoni.

Identification

A member of the tenuis group. The characteristic strong sulcate sculpture of this species, coupled with its possession of immarginate and unarmed lateral pronotal margins, stalked-suborbicular cephalic hairs, and propodeal spines which are bowed outwards in dorsal view and downcurved in profile, make jacksoni very easily recognizable. (Bolton 1982)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Cameroun (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.

  • jacksoni. Cataulacus jacksoni Bolton, 1982: 360 (w.) CAMEROUN.

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

Description

Worker

Holotype. TL 3.5, HL 0.98, HW 0.94, CI 96, EL 0.46, OI 50, SL 0.49, SI 52, PW 0.68, AL 0.98 (cephalic measurements approximate as head crushed).

With the head in full-face view the sides behind the eyes minutely denticulate. Occipital crest absent, the dorsum rounding into the occipital margin. Head of holotype crushed behind level of eyes and the surface fractured; the fracture also running forward on the head along the inner margin of the right eye to the clypeus. With the alitrunk in profile the dorsal outline rising steeply to about the midlength of the pronotum. Behind this the remainder of the dorsum evenly shallowly convex to the bases of the propodeal spines, the outline not interrupted by superficial peaks or tubercles. Mesokatepisternal tooth small and broadly triangular. Propodeal spines in profile strongly downcurved along their length. Metapleural lobes very small. With the alitrunk in dorsal view the pronotal corners angular, the angle slightly projecting. Sides of pronotum behind this not marginate, without a regular series of laterally projecting denticles. Instead the sides with only a blunt tubercle at the point of junction of the pronotum and mesonotum and with one or two minute irregularities, too low, small and blunt to be called tubercles or denticles, situated behind the corner. Sides of mesonotum and propodeum unarmed and immarginate, the latter with a low salient welt at the site of the spiracle. Propodeal spines in dorsal view curved, bowed outwards along their length. Petiole in profile blunt above, not rising to a sharp peak. Subpetiolar process with the anteroventral angle rounded, the posteroventral angle acute and slightly projecting. Postpetiole in profile very high and narrow, with a flat anterior face and a long simple ventral process. In dorsal view the postpetiole with the sides converging dorsally so that the node narrows from base to apex. Dorsum of head to level of posterior margins of eyes finely longitudinally rugose, behind this level the head with very heavy broad strong sulci. Ventral surface of head longitudinally sulcate. Dorsal alitrunk regularly strongly longitudinally sulcate except for the area between the bases of the propodeal spines where the sulci are arched-transverse. Propodeal declivity transversely sulcate. Coxae, femora and tibiae of legs all longitudinally sulcate. Anterior face of petiole node transversely sulcate, the dorsum with U-shaped sulci. Upper half of anterior face of postpetiole vertically sulcate. Sides of alitrunk diagonally sulcate from anteroventral to posterodorsal on each sclerite except on the mesokatepisternum where they run from posteroventral to anterodorsal. First gastral tergite and first sternite covered with strong parallel longitudinal sulci throughout. Dorsum of head with abundant stalked-suborbicular hairs which have slender basal stems. Remainder of dorsal surfaces of body with sparse fine curved hairs which are very feebly clavate apically. Colour uniform black but scapes, anterior tibiae and tarsi, and tarsi of middle and hind legs dull yellow.

Type Material

Holotype worker, Cameroun: Nkoemvon, 1980 (D. Jackson) (The Natural History Museum).

References