Cardiocondyla yoruba

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Cardiocondyla yoruba
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Cardiocondyla
Species: C. yoruba
Binomial name
Cardiocondyla yoruba
Rigato, 2002

Cardiocondyla yoruba casent0901752 p 1 high.jpg

Cardiocondyla yoruba casent0901752 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Cardiocondyla yoruba.

Identification

No distinctive features, but with a combination of characters which make it different from any other Afrotropical Cardiocondyla. Its closest relative seems to be Cardiocondyla emeryi Forel from which C. yoruba may be easily separated by its minor size (compare measurements with those reported in Bolton, 1982), shallower metanotal groove and, in dorsal view, differently shaped petiolar node. (Rigato 2002)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Nigeria (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Little is known about Cardiocondyla yoruba. 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.

  • yoruba. Cardiocondyla yoruba Rigato, 2002: 169, figs. 6, 7 (w.) NIGERIA.

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 1.6, HL 0.42, HW 0.32, CI 76, SL 0.27, SI 84, PW 0.23, AL 0.45.

In full face view head rectangular, longer than wide, the sides appearing slightly convergent in front of the eyes, anterior edge of the clypeal lobe hardly emarginate and occiput weakly concaye. Maximum eye diameter 0.10 mm (8 ommatidia in the longest row). With the alitrunk in profile the promesonotum, as well as the dorsum of the propodeum, forming a low convexity; metanotal groove very shallow. Pronotum in dorsal view with rounded humeri and promesonotum with posteriorly weakly converging sides. Propodeal spines well developed, but short and with a broad base. Petiole in profile with a well developed node, in dorsal view the node is rounded and about as long as wide; in posterior view it appears widely rounded. Subpetiolar process small and protruding in front. Postpetiole in dorsal view about 1.5 times wider than long and about 1.5 times wider than the petiole.

Mandibles mostly smooth. Dorsum of the head regularly areolate, each pubescence-bearing areola finely sculptured. Dorsum of promesonotum similarly, but less regularly areolate; posteriorly and laterally the alitrunk becomes finely reticulate-punctate.

Petiole and postpetiole shagreened on the dorsum, the petiole laterally finely reticulate-punctate. Gaster smooth with a very superficial sculpture near the base and regular pubescence-bearing punctulation.

Erect hairs present only on the anterior clypeal margin and at the tip of the gaster. Appressed pubescence well developed on head, gaster and appendages, less abundant on the alitrunk. On the gaster, the pubescent hairs are about as distant from one another as their length or less.

Colour testaceous with a brown gaster. Antennal club slightly infuscated.

Paratypes. TL 1.6-1.7, HL 0.42-0.43, HW 0.31-0.33, C1 74-78, SL 0.26-0.27, S1 81-84, PW 0.21-0.24, AL 0.43-0.47 (9 measured).

Very consistent with the holotype in size, measurements, sculpture and colour. Minor variations occur in the shape of the propodeal spines, concavity of the edge of the anterior clypeal lobe. The metanotal groove is sometimes fainter in profile.

Type Material

Holotype worker: NIGERIA: Ibadan, UTA xi-1987 (J. Noyes) The Natural History Museum. Paratypes: 9 workers with the same data as the holotype. BMNH

Etymology

A noun in apposition: it is the name of the main human population living in SW Nigeria.

References