Cataulacus longinodus

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Cataulacus longinodus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. longinodus
Binomial name
Cataulacus longinodus
Forel, 1912

Cataulacus longinodus casent0909238 p 1 high.jpg

Cataulacus longinodus casent0909238 d 1 high.jpg

Specimen Labels

The type, a lone female, is the only known specimen of Cataulacus longinodus.

Identification

A member of the granulatus group. This species is distinct from other members of the granulatus group in a number of characters. It is distinguished from Cataulacus simoni, which it resembles most, by its larger size, more coarse sculpturation and lack of clavate hairs on the pronotum; and from other related species by the possession of a complete occipital crest, bicoloured tibiae, relatively narrow head and large eyes. The worker of this species may probably be similar to Cataulacus setosus but with relatively larger eyes, narrower head, more regular sculpturation and shorter propodeal spines.

The name Cataulacus longinodus is something of a misnomer for although the node is relatively longer and narrower than in Cataulacus granulatus it is by no means exceptional to the group as a whole. The petiole is in fact relatively shorter and broader than in queens of simoni.

Regional Cataulacus Key

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Indonesia (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

Only known from the queen caste.

Nomenclature

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

  • longinodus. Cataulacus granulatus var. longinoda Forel, 1912n: 60 (q.) INDONESIA (Sumatra). Raised to species: Bolton, 1974a: 67.

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

Description

Queen

Bolton (1974) - Holotype. TL 5.5, HL 1.20, HW 1.20. CI 100, EL 0.48, OI 40, IOD 0.96, SL 0.64, SI 53, PW 1.08, AL 1.60, MTL 0.67.

Occipital crest complete. shallowly concave, armed with denticles along its length; the denticles largest laterally, becoming gradually smaller towards the middle of the crest. Occipital corners each with a larger, slightly upcurved tooth. Eyes large; the sides of the head behind the eyes virtually without denticles. Edges of frontal carinae smooth, not jagged or crenulate. Sides of pronotum distinctly denticulate. Propodeum with a pair of short, narrow, acute spines. Petiole with dorsal surface convex, the subpetiolar process simple, subrectangular. First gastral tergite 1.83 long, 1.26 wide, marginate basally, this margination extending for a short distance on the sides of the sclerite.

Head reticulate-rugose with the cross-meshes incomplete in places and suppressed medially so that the rugae have a longitudinal trend, particularly in the middle of the dorsum. Pronotum with a coarse and disorganized rugoreticulum, but on the scutum and scutellum the rugae are longitudinal. On the propodeal dorsum two groups of rugae diverge from the anterior margin of the segment toward the spines and there is a subtriangular gap between the groups occupied by a few transverse rugae which continue on the declivity. First gastral tergite with some very fine meandering rugulae superimposed upon a fine, dense reticulate-puncturation.

Short, thick, hairs abundant, on the head some of these are gradually thickened from base to apex and appear clavate. Dorsal surfaces of middle and hind tibiae yellow, the ventral surfaces dark brown or black.

Type Material

Bolton (1974) - Holotype female, SUMATRA: Indrapura (Tritschler) (MHN, Geneva) [examined].

References