Cataulacus praetextus

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Cataulacus praetextus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cataulacus
Species: C. praetextus
Binomial name
Cataulacus praetextus
Smith, F., 1867

Cataulacus praetextus P casent0280798.jpg

Cataulacus praetextus D casent0280798.jpg

Specimen Label

Synonyms

An arboreal nester, based on one of the few known specimens reported as being from canopy fogging, nothing else is known about the biology of Cataulacus praetextus.

Identification

A member of the taprobanae group. Cataulacus praetextus is distinguished from its immediate congeners by the form of sculpturation, great reduction of hairs, especially on the legs, the laterally marginate first gastral tergite and the projection of the occipital crest. It appears to be closest related to Cataulacus reticulatus and Cataulacus catuvolcus. The male is distinguished by the rather odd bands of long thick hairs on each visible gastral tergite behind the first. (Bolton 1974)

Keys including this Species

Distribution

Known from Indonesia (Sumatra) and Malaysia (Sarawak, Borneo) with the type collected from an unspecified locale in Borneo.

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo (type locality), Indonesia, Malaysia.

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.

  • praetextus. Cataulacus praetextus Smith, F. 1867: 528, fig. 5 (w.) BORNEO. Bolton, 1974a: 81 (q.m.). Senior synonym of sumatrensis: Bolton, 1974a: 80.
  • sumatrensis. Cataulacus praetextus var. sumatrensis Forel, 1912n: 60 (w.) INDONESIA (Sumatra). Viehmeyer, 1916a: 140 (q.). Junior synonym of praetextus: Bolton, 1974a: 80.

The following notes on F. Smith type specimens have been provided by Barry Bolton (details):

Cataulacus praetextus

Holotype worker in Oxford University Museum of Natural History. Labelled “Borneo.”

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 5.2 – 6.0, HL 0.90 – 1.04, HW 0.94 – 1.10, CI 104 - 106, EL 0.36 – 0.40, OI 36 - 38, I0D 0.72 – 0.80, SL 0.48 – 0.52, SI 47 - 51, PW 0.76 - 0'92, AL ca 1.00, MTL 0.48 - 0.52 (2 measured).

Bolton 1974 fig 35-37
Occipital crest complete, the median portion raised into a low, projecting ridge in full-face view; entirety of crest without denticles. Sides of head behind eyes denticulate, sometimes not very distinctly so, the occipital corners with a low, broad, triangular tooth. Sides of pronotum with a rectangular shallow expansion, the margins of which have one or two feeble teeth or crenulations anteriorly. Sides of mesonotum roughly triangular in dorsal view, with a distinct U- or V-shaped notch or impression separating them from the propodeum. Propodeum behind this notch with a short free anterior face. Sides of propodeum marginate, continuous with the sides of the spines, the margins with three to five denticles. First gastral tergite marginate laterally throughout its length, the margination most distinct basally.

Dorsal surfaces of head and alitrunk with a fine rugoreticulum with the interspaces finely and densely reticulate-punctate. The sculpturation has approximately the same intensity on all parts of the dorsal alitrunk. Dorsal surfaces of pedicel similarly but more loosely sculptured; the first gastral tergite finely and very densely reticulate-punctate with numerous short rugulae, the majority of which are longitudinal.

Dorsal surfaces of head, alitrunk and first gastral tergite without hairs. Hairs are, however, present on the mandibles and a row of short, flattened hairs adorns the margin of each frontal carina. Sides of head behind eyes with a row of very short, flattened hairs which project beyond the lateral margins in full-face view. Lateral margins of alitrunk with a few similar hairs. Dorsal surfaces of femora and tibiae without hairs except for one or two which may be present at the extreme apices of the latter.

Queen

Bolton (1974) - Putative. TL 5.2 – 6.0, HL 1.04 – 1.14, HW 1.14 – 1.30, CI 109 - 114, EL 0.40 – 0.44, OI 35, IOD 0.82 – 0.94, PW 1.02 – 1.16 (2 measured).

Similar to worker, the median projecting portion of the occipital crest distinct. Denticulation of sides of head behind eyes less well developed; the expansions of the sides of the pronotum much reduced, with a small but distinct triangular tooth at the beginning of the lateral margination on each side. Propodeal spines smaller than in worker, the sides of the first gastral tergite not marginate. Sculpturation of head, pronotal dorsum, propodeum, pedicel and first gastral tergite as worker but the scutum and scutellum longitudinally rugose, the spaces between the rugae finely reticulate-punctate. Hairs distributed as in worker but one or two erect hairs may be present on the femora.

Male

Bolton (1974) - Putative. TL 4.8 - 5.2, HL 0.86 – 0.88, HW 1.02 – 1.06, CI 118 - 120, EL 0.36 - 0.38, OI 34 - 37, IOD 0.78 – 0.84, SL ca 0.50, SI 47 - 49, PW 0.96 – 1.00, AL 1.56 – 1.61, MTL ca 0.72 (4 measured).

Occipital crest complete, unarmed, the median portion raised and projecting as in the worker. Sides of head behind eyes not denticulate, usually feebly sinuate. Occipital corners in the form of projecting, broad, triangular angles. Frontal groove distinct, not reaching the median ocellus. Sides of pronotum not expanded, without denticles. Anterior arms of notauli distinct at least anteriorly and with cross-ribs, the posterior arm indistinct or absent. Parapsidal furrows present. Propodeal spines broad basally, rapidly converging to an acute apex. First gastral tergite not marginate. Parameres in side view with a strong, thick brush of hairs ventrally.

Sculpturation somewhat variable. Head usually reticulate-punctate everywhere with a superimposed fine rugoreticulum posteriorly on the dorsum and fine, more definitely longitudinally directed rugulae anteriorly, the change in sculpturation taking place more or less at the level of the median ocellus. On the most finely sculptured individuals the rugulae are virtually absent from the anterior half of the head. Dorsum of alitrunk reticulate-punctate with sparse longitudinal rugulation on the mesonotal sclerites and a fine rugoreticulum upon the propodeum. Gaster very finely reticulate-punctate and dully shining. Erect hairs sparse everywhere but the second to fifth gastral tergites inclusive with a transverse row of many long, thick, blunt hairs, entirely absent from the first tergite.

Type Material

Bolton (1974) :

Holotype worker, BORNEO (UM, Oxford) [examined].

Cataulacus praetextus var. sumatrensis Holotype worker, SUMATRA: Indrapura (Tritschler) (MHN, Geneva) [examined].

References