Ocymyrmex celer

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Ocymyrmex celer
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Ocymyrmex
Species: O. celer
Binomial name
Ocymyrmex celer
Weber, 1943

Ocymyrmex-celer-Syntype-MCZ26125L.jpg

Ocymyrmex-celer-Syntype-MCZ26125D.jpg

Syntype Specimen Label

Nothing is known about the biology of Ocymyrmex celer.

Identification

Bolton (1981) - Along with Ocymyrmex nitidulus this species can be separated from all others in which the clypeus is impressed and the first gastral segment constricted by the slick and glossy appearance of the head. In all others the ground-sculpture on the head consists of quite conspicuous granulation or punctulation, but in celer and nitidulus this is very reduced or absent, leaving the spaces between costulae smooth or very nearly so, and shining. The two may be distinguished by the shape of the pronotum, which in nitidulus is convex and, together with the mesonotum, forms an evenly convex surface. In celer the pronotum is flat and an even convexity does not result.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Sudan (type locality).

Distribution based on AntMaps

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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 from workers and queens.

Nomenclature

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

  • celer. Ocymyrmex weitzeckeri subsp. celer Weber, 1943c: 368 (w.) SUDAN. Bolton & Marsh, 1989: 1278 (q.). Raised to species: Bolton, 1981b: 267.

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

Description

Worker

Bolton (1981) - TL 8.1-8.5, HL 1.98-2.04, HW 1.82-1.88, CI 91-94, SL 1.68-1.73, SI 89-95, PW 1.12-1.16, AL 2.30-2.46 (4 measured).

Anterior clypeal margin with a conspicuous median impression which is flanked on each side by a low broad tooth. Sides of head in front of eyes more or less parallel in full-face view, not obviously diverging anteriorly as is frequent in the genus. Maximum diameter of eye 0.38-0.39, about 0.21 x HW. Dorsum of pronotum in profile flat to indented, sloping upwards behind to its junction with the mesonotum; the promesonotum not forming a single even convexity. Dorsum of propodeum rounding broadly and evenly into the sloping declivity. Metapleural lobes deep but narrow, rounded and little projecting. Petiole node in profile small, low and rounded, in dorsal view longer than broad. Postpetiole in dorsal view slightly longer than broad. First gastral tergite with a neck-like constriction basally. Dorsum of head finely densely and regularly longitudinally costulate, the costulae low and superficial, weakly developed, parallel and arching outwards behind the eyes. Spaces between the costulae highly polished, without strong granular or punctulate ground-sculpture; the whole head with a slick and glossy appearance. Pronotum with weak to feeble arched-transverse costulate sculpture dorsally, which may be almost effaced centrally, the space between the mesothoracic spiracles with longitudinal or transverse costulate sculpture. Remainder of dorsal alitrunk transversely and more strongly costulate. Sides of alitrunk regularly densely sharply costulate everywhere. Petiole node with transverse rugulae ventrally which may extend for some distance up the sides, and with faint rugulae on the dorsal peduncle, but the dorsum of the node unsculptured or only with the faintest vestiges present. Postpetiole only with superficial patterning. All dorsal surfaces of head and alitrunk with numerous hairs of varying length; first gastral tergite with hairs shorter and much sparser than on alitrunk. Colour glossy dull red, the gaster dark brown.

Type Material

Bolton (1981) - Syntype workers, Sudan: Torit, N. oflmatong Mts, 6.viii.l939, no. 1462 (N. A. Weber) (Museum of Comparative Zoology) [examined].

References