Ocymyrmex monardi

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Ocymyrmex monardi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Ocymyrmex
Species: O. monardi
Binomial name
Ocymyrmex monardi
Santschi, 1930

Ocymyrmex monardi casent0217898 p 1 high.jpg

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Specimen Labels

Nothing is known about the biology of Ocymyrmex monardi.

Identification

A member of the weitzeckeri group. This moderately sized quite darkly coloured species is closely related to Ocymyrmex fortior, but is separated from it and from other close forms by the distinctive pattern of sculpture on the head. (Bolton 1981)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Angola (type locality), Namibia, South Africa.


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 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.

  • monardi. Ocymyrmex weitzeckeri st. monardi Santschi, 1930b: 68 (w.) ANGOLA. Raised to species: Bolton, 1981b: 273.

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 7.4-8.1, HL 1.78-1.88, HW 1.68-1.86, CI 95-99, SL 1.60-1.72, SI 92-95, PW 1.06-1.24, AL 2.22-2.40 (3 measured).

Anterior clypeal margin medially with a distinct semicircular impression which is flanked on each side by a small tooth. Eyes with maximum diameter 0.37-0.40, about 0.21-0.22 x HW. Promesonotum in profile evenly rounded, sloping posteriorly to the propodeum which itself slopes very shallowly to the evenly rounded posterior angle where the dorsum meets the declivity. Metapleural lobes small, broadly rounded to truncate posteriorly, not triangular. Metapleural glands not strongly swollen nor strongly projecting posteriorly, in profile not concealing even the bases of the metapleural lobes. Petiole in profile with the node evenly rounded, dome-like; in dorsal view the node as broad as long or slightly longer than broad. Postpetiole in dorsal view very slightly longer than broad. Base of first gastral tergite constricted. Sculpture on dorsum of head characteristic; space between frontal lobes and median strip of dorsum behind the frontal lobes finely and densely longitudinally costulate, with feeble punctulate ground-sculpture between the costulae. Behind the level of the eyes the costulae of this median area become much weaker and show signs of diverging, or fade out altogether, being replaced partially or entirely by coarse punctulate or granular sculpture which is very dense and conspicuous. The space between the inner margin of the eye and the antennal fossa, and the area extending back from this level to the occiput covered with dense irregular granular sculpture. Dorsal alitrunk and propodeal declivity transversely rugose except for the space between the mesothoracic spiracles and the median strip of the pronotum in front of this level, where the rugae are longitudinal. Petiole and postpetiole unsculptured except for faint superficial patterning or the former at most with a few vestigial transverse rugulae ventrally. All dorsal surfaces of head and body with hairs, but those on the first gastral tergite shorter and much sparser than on the alitrunk, where strong hairs are conspicuous. Alitrunk dull red to reddish tinted black, the head somewhat lighter in shade.

Type Material

Bolton (1981) - Syntype workers, Angola: Cakindo (A. Manard) (Naturhistorisches Museum, Basel) [examined].

References