Ocymyrmex flavescens

AntWiki - Where Ant Biologists Share Their Knowledge
Jump to: navigation, search
Ocymyrmex flavescens
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Ocymyrmex
Species: O. flavescens
Binomial name
Ocymyrmex flavescens
Stitz, 1923

Ocymyrmex flavescens focol2186 p 1 high.jpg

Ocymyrmex flavescens focol2186 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Ocymyrmex flavescens.

Identification

Its closest relatives include Ocymyrmex afradu and Ocymyrmex kahas. kahas and flavescens have the gaster yellowish, afradu has the gaster black; kahas and flavescens have the petiolar peduncle longer than the node whilst afradu has the node slightly longer than the peduncle. In full-face view the occipital margin is more strongly indented medially in afradu and flavescens than in kahas, and in afradu the petiole node is long, low and subclavate in profile. (Bolton 1981)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Namibia (type locality).

Distribution based on AntMaps

AntMapLegend.png

Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Little is known about the biology of this species but a few species of Ocymyrmex have been studied in some detail. From this we can form some ideas about the biology of the genus as a whole. The following is summarized from Bolton and Marsh (1989). More details can also be found on the Ocymyrmex genus page.

Arnold (1916) observed that Ocymyrmex species with which he was acquainted nested in the ground in hot arid areas. The nests themselves went very deep into the ground, usually in loose sandy soil, and had a crater-like entrance. The ants used their well-developed psammophores to carry soil particles excavated from the nests. Recently both Marsh and Robertson (pers. comm.) have observed that workers of Ocymyrmex fortior close the nest entrance with small stones during periods of nest inactivity. Also, in Zimbabwe, fortior workers have been seen adding small stones to the crater-like nest entrance that were picked up from the ground some distance away from the nest. Species are now known which nest in very rocky soil and the nests may extend through the bedrock itself, necessitating the use of a large crowbar to expose the nest-chambers (H. Robertson, pers. comm.). Careful excavations of nests in well-structured sandy soil by one of us (Marsh) have revealed a simple nest structure. For example, nests of foreli typically have one entrance that opens into a vertical tunnel which terminates in a broad chamber at a depth of about 30 cm. Other brood and food chambers branch off from the tunnel at various intermediate levels. In most nest excavations the ergatoid queen was discovered near the bottom of the nest. In very unstructured loose sand, such as in the dry river beds of the Namib Desert, the tunnels and chambers of Ocymyrmex nests followed the root systems of shrubs and trees, and the major tunnel was therefore not necessarily vertical. Colonies of Ocymyrmex range in size from 200 to 1000 individuals (Marsh, 1987).

Other general aspects of their biology include workers that move rapidly, erratically, and are often active during the hottest part of the day. Specifics of their diet seem to vary by species but can include seeds and insects. For most species where queens are known they are worker-like ergatiod forms that are nonetheless clearly a morphologically distinct caste, as opposed to many intercaste ergatiods known from other genera that are intermediate between workers and more robust queens. Males of Ocymyrmex are often collected at lights but males associated with conspecific workers and females have rarely been collected.

Castes

Known only from the worker caste.

Nomenclature

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

  • flavescens. Ocymyrmex barbiger var. flavescens Stitz, 1923: 147 (w.) NAMIBIA. Junior synonym of barbiger: Bolton, 1981b: 265. Revived from synonymy and raised to species: Bolton & Marsh, 1989: 1294.

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

Description

Worker

TL 5.2, HL 1.32, HW 1.24, CI 94, SL 1.20, SI 97, PW 0.78, AL 1.50.

Clypeus with a small median impression which is flanked by a rounded prominence of the lamellate anterior clypeal margin on each side, rather than being flanked by a pair of teeth. Lamellate anterior margin of clypeus very broad and conspicuous. In full-face view the eyes just intersect the outline of the sides of the head. Propodeal dorsum in profile rounds broadly and evenly into the declivity, the latter a long sloping surface which is by no means vertical. Petiole node in profile low and shallowly convex, the node itself distinctly separated from the anterior peduncle; entire petiole not elongate-claviform. Postpetiolar sternite ventrally broad and very shallowly evenly transversely concave, almost flat across its width, without a median longitudinal groove. In profile both the first gastral tergite and sternite convex from their articulation with the postpetiole. In dorsal view the postpetiole-gastral articulation broad and the first tergite without a basal constriction or neck. Head to level of eyes densely and regularly, but only faintly to superficially, longitudinally costulate. The spaces between the costulae have weak superficial ground-sculpture. Behind the level of the eyes the costulae become fainter than in front of them and tend to fade out entirely close to the occipital margin. Dorsolaterally on the head the ground-sculpture becomes more obvious, and mesad of the inner margins of the eyes it appears as lines of weak reticulation or punctation separated by narrow costular walls. Sculpture of pronotal dorsum very faint, vestigial in places. Mesonotum and propodeal dorsum transversely weakly rugulose. Ventral surface of petiole node with transverse short rugae, but sides and dorsum of petiole, and entirety of post petiole, faintly superficially reticulate only. All dorsal surfaces of head and body with standing hairs, but these are not strikingly dense and may be abraded in the syntype. First gastral tergite with several elevated hairs, which are about equal in length to those on the propodeum. Colour entirely yellow.

Type Material

Syntype worker, Namibia: Okaputa, 5. v .1911 (w. Michaelsen) (Berlin Museum für Naturkunde der Humboldt-Universität) [examined].

References