Cataulacus satrap

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

Cataulacus satrap P casent0900273.jpg

Cataulacus satrap D casent0900273.jpg

Specimen Label

Nothing is known about the biology of Cataulacus satrap.

Identification

A member of the tenuis group. Related to Cataulacus vorticus which it resembles closely, Cataulacus satrap is immediately separated by its possession of denticles on the lateral pronotal margins.

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.

  • satrap. Cataulacus satrap Bolton, 1982: 363 (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 0.87, HW 0.82, CI 94, EL 0.44, OI 53, SL 0.40, SI 49, PW 0.56, AL 0.96.

With the head in full-face view the sides behind the eyes minutely denticulate, the denticles partially concealed by the thickened short hairs which project above them; the row of denticles ends in a small tooth at the occipital corner. Occipital crest absent, the dorsum of the head rounding into the occipital surface. Occipital margin unarmed except for a small tooth close to the one at the corner. Eyes relatively large, OI > 50. In profile the anterior outline of the pronotal dorsum sloping steeply, the surface equipped with a number of low peaks or tubercles. Behind this the remainder of the alitrunk shallowly but evenly convex, sloping down posteriorly to the base of the propodeal spines. Mesokatepisternal tooth prominent, moderately well developed. Metapleural lobes low and rounded. Propodeal spines in profile straight, only slightly elevated. With the alitrunk in dorsal view the pronotal corners angular and projecting. Sides of pronotum behind the corners only weakly marginate and with a series of 4-5 projecting denticles, all of which are small and widely spaced. In the holotype the right pronotal margin with 5, the left with 4 denticles. On both sides the posteriormost denticle the largest, the anteriormost distinctly smaller; the 2-3 between them minute and inconspicuous. Sides of mesonotum and propodeum without differentiated denticles. Propodeal spines in dorsal view broad and feebly divergent. Petiole in profile rising to an acute peak above. Subpetiolar process simple, with a bluntly rounded anteroventral angle and an acute, weakly projecting posteroventral angle, the two separated by a flat ventral surface. Postpetiole dome-like and high in profile, with two feebly developed peaks dorsally; the subpostpetiolar process short-digitiform and blunt. Dorsum of head irregularly reticulate-rugulose, the reticular meshes of uneven size and irregular shape, the rugulae low and rounded. Ground-sculpture of the rugular meshes a fine dense reticulate-puncturation. Dorsal alitrunk densely covered in fine rugulae which are low and rounded, reticulate in places but predominantly longitudinal behind the pronotum. Entire dorsum of alitrunk also blanketed by a fine dense and very conspicuous reticulate-punctate ground-sculpture. Petiole and postpetiole with dense reticulate-punctate sculpture, the former also with longitudinal rugae in dorsal view, the latter only with a few vestigial irregular rugulae. First gastral tergite strongly and densely reticulate-punctate everywhere. Dorsum of head with numerous distinctive stalked-suborbicular hairs, those situated anteriorly on the dorsum more strongly expanded apically than those situated behind the level of the eyes. All remaining dorsal surfaces of body with many very short thick blunt hairs. Colour uniform black, dull; the scapes, tibiae and tarsi dull yellowish brown.

Paratype. TL 3.4, HL 0.88, HW 0.80, CI 91, EL 0.43, OI 54, SL 0.40, SI 50, PW 0.57, AL 0.96.

As holotype but propodeal spines slightly less divergent and the subpetiolar process with the anteroventral and posteroventral angles separated by a feebly concave ventral surface. On the pronotal margins the anteriormost denticle behind the corner is no larger than those following it (except for the last in the row, which is the largest); and the left side of the pronotum with 5 denticles, the right side with 4.

Type Material

Holotype worker, Cameroun: Nkoemvon, 1970, M12 (D. Jackson) (The Natural History Museum). Paratype. 1 worker with same data as holotype (BMNH).

References