Cardiocondyla sekhemka

AntWiki - Where Ant Biologists Share Their Knowledge
Jump to: navigation, search
Cardiocondyla sekhemka
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cardiocondyla
Species: C. sekhemka
Binomial name
Cardiocondyla sekhemka
Bolton, 1982

Cardiocondyla sekhemka casent0901749 p 1 high.jpg

Cardiocondyla sekhemka casent0901749 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Cardiocondyla sekhemka.

Identification

This small, virtually unsculptured darkly coloured species is easily recognised by its relatively short scapes, broad head, characteristically shaped eyes, lack of developed propodeal spines and feebly impressed metanotal groove followed by a depressed propodeum. In the Afrotropical region only Cardiocondyla wroughtonii approaches the CI value of sekhemka, but in that species the propodeal spines are long and strongly developed. Only Cardiocondyla shuckardi has the propodeal armament as feebly developed as in sekhemka but here the head and body are usually strongly sculptured, the eye is not drawn out anteroventrally, and the dimensions are very different. (Bolton 1982)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Ghana (type locality).

Distribution based on AntMaps

AntMapLegend.png

Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Little is known about Cardiocondyla sekhemka. Until further studies reveal more about this species we can infer that its natural history and biology is likely similar to other members of the genus. Seifert revised the holarctic species of Cardiocondyla in 2003 and the following synopsis is based on his excellent treatment of the genus. References to other publications and more details about what is reported here can be found in Seifert (2003).

Many Cardiocondyla species inhabit areas that experience frequent disturbance and/or are quite open. These may be human altered areas, where a number of Cardiocondyla tramp species thrive, but also natural areas such as semi deserts and steppes, immature soils at rivers, lakes, and sea shores and to a lesser extent forest margins or burned-down woodland patches. In contrast to this open-land group, the natural habitat affinities of many tropical species are primary rain forests.

Nests are typically in soil and sometimes under stones. Two species are known to nest in vegetation but this is unusual for the genus. The single nest entrances is small (1-1.5 mm) and inconspicuous. In the desert nests can be relatively deep (> 1m) and have many chambers but in areas where conditions are less extreme there is generally a single chamber (15-20 mm diameter and 3-4 mm height) that is not far below the ground surface (2-15 cm).

Cardiocondyla tramp species (Cardiocondyla wroughtonii, Cardiocondyla obscurior, Cardiocondyla mauritanica, Cardiocondyla emeryi and Cardiocondyla minutior) are known to be polygynous, as are some less widespread species, while other species are known to be monogynous.

Cardiocondyla ants are omnivorous. Zoophagy (zoo necrophagy and killing of small weakly sclerotised arthropods), granivory, and nectarivory have also been noted. Tandem running has been observed as a method of recruitment to food sources in a few species.

Intranidal mating appears to be the norm for most species in the genus. Mating strategies are species dependent and may take various forms. Winged males may mate within their nest or fly to and enter other colonies to mate. Queen mate intranidally and fly from their nest to begin a new colony, become integrated into their natal colony, or may walk away from their nest and establish a new colony nearby.

Cardiocondyla are unusual in having peculiar male forms. Male polymorphism is found in some species with typical males and an ergatoid form. These latter males are wingless and worker like in appearance. Ergatoid males fight with other males within their natal nest. By killing potential rival males, a dominant male can monopolize matings with the virgin queens in their colony. Morphological modifications that enhance the fighting abilities of ergatoid males have been documented, e.g., modified mandibles well suited to fighting and increased mesosomal size for better protection against attacks from rivals. Another unusual characteristic of ergatoid males is the continuation of spermatogenesis throughout their adult life. Males of most aculeate hymenoptera stop producing sperm once they are fully mature.

Some species are known to produce different queen morphs. This presumably facilitates there being a longer range dispersal queen form and a shorter or non-dispersing form. Gyne polymorphism appears to be an adaptation for species inhabiting continental desert or semi-desert habitats. The cosmopolitan tramp species, on the other hand, do not exhibit this gyne polymorphism.

Castes

Only known from the worker caste.

Nomenclature

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

  • sekhemka. Cardiocondyla sekhemka Bolton, 1982: 315 (w.) GHANA.

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

Description

Worker

Holotype. TL 1.8, HL 0.44, HW 0.38, CI 86, SL 0.28, SI 74, PW 0.12, AL 0.32.

Head relatively short and broad, scapes relatively short (CI and SI, above). When laid back on the head the scapes failing to reach the occipital corners in full-face view. Projecting median portion of clypeus and flattened prominent lateral parts of clypeus closely fused and forming a more or less evenly semicircular projecting lobe which hides most of the mandibles in full-face view (only the two apicalmost teeth of the right mandible can be seen in the holotype). Eyes relatively large, maximum diameter 0.12, about 0.32 x HW and with 10-11 ommatidia in the longest row. Shape of eye irregular in profile, narrowed and drawn out anteroventrally, rounding the lower curve of the sides and onto the margins of the ventral surface of the head. Pronotal corners rounded in dorsal view. With alitrunk in profile the promesonotum evenly convex from front to back, sloping posteriorly to the feebly impressed metanotal groove. Propodeal dorsum more shallowly convex than promesonotum and on a much lower level so that there is a distinct step-down from the promesonotum to the propodeum. Posteriorly the propodeal dorsum sloping down to a pair of broad blunt and very low tubercles which are much shorter than the metapleural lobes and which are shorter than their basal widths. In dorsal view the tubercles distinctly shorter than half the distance separating their bases. Petiole in profile with a short peduncle and rounded node. In dorsal view the petiole node subglobular, slightly broader than long. Postpetiole in dorsal view much broader than long, with a shallowly concave anterior margin and evenly convex sides. Dorsum of head sculptured with widely scattered superficial minute punctulae, the surface between the punctulae smooth and shining. Remainder of body unsculptured, smooth and shining. Hairs absent except on mouthparts and gastral apex. Colour uniform glossy blackish brown, the legs and antennae lighter.

Type Material

Holotype worker, Ghana: Tumu, 24.xii.1969 (P. Room) (The Natural History Museum).

References