Camponotus maculatus species complex

See the Camponotus species groups page for general information about species groups in this genus.

African species

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Specimen labels

Camponotus maculatus Minor

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Specimen labels

The vast majority of species from this group are known from Africa.

McArthur and Leys (2006) performed an analysis of the genetic relationships between African and Australian species from this group. They found: The molecular results showed no support for the assumption that the African species, which are morphologically similar to the Australian species, belong to the same group. Pairwise distances are large (12.1 - 18.4 %) and relationships among these groups are unresolved with the inclusion of some species that clearly do not have “maculatus” morphological features. The very deep divergences among the unresolved clades of species indicate that these clades would be better assigned to different species groups.

Australian species

McArthur and Leys (2006)

Notes

Camponotus maculatus (Fabricus, 1782) has accumulated over 100 subspecies and although the major worker of the species type has been adequately described and re-described (Donisthorpe 1922), the minor worker has not been. Characters of minor workers are most useful for defining species boundaries in Camponotus. A.J.M. has examined the type specimen in BMNH of a major worker. It was collected by Captain Cook and believed to be from Sierra Leone. Most of the described taxa of the C. maculatus group are from Africa and thirty-nine of them have been raised to species rank (Baroni Urbani 1972). It is assumed the species name derives from the Latin macula = blotch or stain because of patches of lighter colour on its mesosoma.

One subspecies, Camponotus maculatus humilior (now raised to species) has been described from Australia and it and its relative, Camponotus novaehollandiae are common ants of northern Australia. These three species possess strikingly similar morphological characters to some specimens of Camponotus maculatus subspecies collected from Africa and now in the Humboldt Museum, Berlin and in the Natural History Museum, Vienna.

The Camponotus species targeted for this study possess the following distinguishing characters and are loosely referred to as the C. maculatus group herein:

1. The most striking character is the distinct occipital carina in minor workers (Fig. 1). This forms a ridge externally and probably serves to strengthen the anterior parts of the head (Snodgrass 1935), it is absent in major workers.

2. Strong dimorphism, i.e., workers encountered are mostly either major or minor, medium workers are non existent or very scarce.

3. The sides of the heads of major workers taper strongly to the front (Fig. 2) while in minor workers, the sides are mostly parallel and taper to the rear.

4. The vertex in major workers is concave or flat, in minor workers it is convex.

5. The scape and tibiae have plentiful short setae, raised up, more so in Australian than in African species.

6. Biology: (a) mostly nocturnal, (b) nests are in clay soil, never in sand, (c) entrances to nests are well hidden, (c) strong attraction to honey bait at night, (d) domination at honey bait, (e) quickly scatter when disturbed by torch light.

Other Australian species included in the C. maculatus group viz Camponotus spenceri, Camponotus extensus and Camponotus oxleyi are not considered here because they can be separated from the target species by the integument of the heads of the major workers which are covered with fine punctations and are matte whereas the target species are more smooth and glossy.

McArthur and Leys 2006
Figure 1. Camponotus crozieri minor
Figure 2. Camponotus crozieri major
Camponotus crozieri minor

New World Species

MacKay and Delsinne (2009)

The New World species tentatively placed in the maculatus species complex include:

Camponotus variegatus does not occur in the New World nor Hawaii (see Hansen & Klotz 2005:98-99 and Kirschenbaum & Grace 2007) and specimens are here referred to as C. maculatus, until the Old World species can be clarified.

Notes

The maculatus species complex is principally an Old World group, with a few representatives in the New World (http://www.utep.edu/leb/antgenera.htm). Some of the species may have been introduced, specifically C. maculatus and possibly Camponotus conspicuus zonatus, but the remaining species are probably native to this hemisphere.

The majors of most species in the maculatus species complex are large, brown ants, often with black gasters, and with lateral yellow splotches on each gastral tergum. The heads of most species are elongated, with the sides nearly straight, and strongly narrowed anteriorly. The mandibles are large and usually have seven or more teeth. The anterior border of the clypeus is usually convex, or at least straight, and rarely weakly concave. The clypeal carina is usually well developed. The scapes are long, and usually extend about the first two funicular segments past the posterior lateral corners of the head. The posterior border is usually concave. The mesosoma is elongated, and relatively slender, and the petiole is usually slender when viewed in profile. Most species have abundant erect hairs on most surfaces, especially the head, the mesosoma, petiole, and the gaster. The scapes may or may not have erect hairs, but always have a few erect hairs at the apex. The tibiae lack erect hairs and suberect hairs are rarely present. Appressed hairs are sparse and scattered on many surfaces, especially the head, mesosoma and gaster.

The minor workers are difficult to characterize. Most species have seven mandibular teeth, and the anterior border of the clypeus is usually straight or convex. The head is rectangular shaped or may be widened anterior to the eyes. The scapes extend at least 1/2 length past the posterior lateral corner of the head.

The females are similar to the major workers, except the anterior border of the clypeus is usually concave. There are approximately 50 species complexes of Camponotus present in the New World ([www.utep.edu/lep/antgenera.htm]). Separation of members of the maculatus species complex from other complexes should not present difficulties except separation from the atriceps, picipes and bonariensis species complexes.

Separation of this species complex from theatriceps species complex would be fairly easy, based on the concave anterior border of the clypeus of the majors of the atriceps species complex, and the relatively short, flattened scapes of the majors of the atriceps species complex. Separation of members of the maculatus species complex from the others Camponotus species complexes of the New World should not present difficulties, except separation from the picipes, atriceps and bonariensis species complexes. Separation of members of the maculatus species from other picipes species complex is difficult, and some of the species in the maculatus complex were named as subspecies of C. picipes. The major workers can usually be recognized by the convex or straight anterior clypeal border, which is definitely concave in members of the picipes species complex. Additionally, the head is more elongated in members of the maculatus species complex. The identification of the minors or the females without the associated major workers would be difficult or impossible. It may not be possible to reliably separate the two species complexes, and they could be combined into a single complex in the future.

Members of the maculatus species complex can be confused with those of the bonariensis species complex. They are nearly always larger ants (about 10 mm total length or larger) than the smaller majors of the bonariensis species complex (usually less than 10 mm total length).

References