Cataglyphis bombycinus (Roger, 1859)

Agosti, Donat, 1990, Review and reclassification of Cataglyphis (Hymenoptera, Formicidae), Journal of Natural History 24, pp. 1457-1505 : 1473-1474

bombycinus group

Diagnosis

Workers and females: Cataglyphis ants with the following diagnostic characters:

1. Petiole squamiform, the anterior and the posterior surface laterally confluent.

2. MPI <85; third maxillary palp segment compressed in cross-section, with long erect hairs along the margins and the outer surface, forming a part of the psammophore.

3. Uniform brownish or yellowish, sometimes rather dark and with a gaster darker than the remaining body parts; a thick, long pubescence causes the silvery appearance of the ants.

4. Head sculpture finely reticulate.

5. Alitrunk length of large workers variable, in sabulosus <2-5 mm, in the remaining species up to 5 mm.

6. Mandible with more than five teeth, without the postbasal (Fig. 4); in small workers of sabulosus occasionally only five teeth present.

Males: Cataglyphis ants with the following diagnostic characters:

1. Body colour variable, yellowish to black, unicolourous to bicoloured.

2. Subgenital plate short (SPI <125); with two distal lateral depressed processes and a median part which is variable only a cleft or a third but much shorter process (Fig. 16).

3. Squamula and stipes caudally almost confluent (Fig. 31).

4. Stipes with or without a median appendix which is confluent with the stipes.

5. Volsella straight, the sides subparallel, distally diverging and truncated (Fig. 51).

6. Sagitta with a quadrangular shield (Fig. 66); the teeth of the serrated side extended over the whole face, not curved laterally.

Distribution

The bombycinus species-group is distributed from western Morocco to the Sinai peninsula, at least following the northern side of the Sahara up to Sinai and down to Saudi Arabia. This species group includes the ants living in the most arid habitats, between the sand dunes of the deserts where Aristida spp. occur. This group is an ecological equivalent to pallidus from the Kara Kumy of Turkmeniya.

Comments

The species of the bombycinus species-group show the most elaborate dimorphism within Cataglyphis and a unique biology. Although they are individual foragers, they tend to leave the nest in groups soon after dawn and before dusk, and are rarely seen foraging in the heat of the day (Wehner, personal communication). The bombycinus species-group includes two species-complexes:

(i) bombycinus complex: diagnosed by the male genitalia with a trilobed subgenital plate (Fig. 16), the presence of a median appendix of the stipes which is not separated basally by a carinae, and large (AL> 5 mm) dimorphic workers with a soldier caste with falcate mandibles (Fig. 5) and workers with always six or more teeth on the mandible. The worker castes are characterized by an astonishingly high variation in coloration and the whole bombycinus complex nevertheless may consist of only two species; bombycinus with workers with a thick, silvery pubescence on the gaster and lucasi with a sparse pubescence with hairs shorter than the distance between them. Distribution: deserts of North Africa and Sinai.

(ii) sabulosus complex: diagnosed by the truncated lateral appendices of the subgential plate, a large, simple, median appendix of the stipes of about half the length of the stipes and smaller, monomorphic, workers (AL <2-5 mm), with sometimes small teeth on the mandibles which have almost been reduced to five teeth. The complex includes one species ( sabulosus ) and a second species has to be described (CCAC). Further analysis is needed to prove whether the sabulosus complex is the sister group of the bombycinus complex or of the emmae complex, with which it shares the long median appendix of the stipes and the truncated subgenital plate. Distribution: Sinai, Oman.