Cataulacus erinaceus

Cataulacus erinaceus is an arboreal nester.

Identification
A member of the guineensis group. This species is very easily recognizable due to its large size and distinctive sculpturation. The form and denticulation of the alitrunk also help to separate Cataulacus erinaceus from the closely related Cataulacus guineensis. Forel (1916: 427) described the female of this species, which does not differ markedly from the worker. The male remains unknown, as in the majority of African species of Cataulacus. (Bolton 1974)

Key to Afrotropical Cataulacus Species

Distribution
Known from Cameroun Democratic Republic of Congo, Equatorial Guinea, Guinea, Ghana and Liberia.

This taxon was described from Equatorial Guinea.

Biology
Wheeler (1922) notes that erinaceus was found in Zaire (Democratic Republic of Congo) running up and down large trees. C. A. Collingwood collected the species from trees in the primary forest reserve of Mount Atewa, Ghana, and the present author has observed individuals in the same locality running upon the moss-covered trunks of living trees and also crawling along the tendrils of a thorny creeper in a clearing. Specimens from the Du River were taken from a nest 'under moss in the bark of a big tree, 20 ft above ground'. (Bolton 1974)

Cataulacus erinaceus has been collected from a nest in the canopy of a secondary-forest tree, in sampling conducted in tree crowns, in Gamba, Gabon. It was anecdotally reported to monopolize a tuna bait. C. erinaceus has been shown to exhibit directed movement while in freefall that allows workers that fall or purposely detach from a tree to glide back and regain a hold on the same tree trunk. This gliding behavior is shared with numerous members of the tribe Cephalotini, and other genera as well. (Yanoviak et al. 2005, 2007, 2008)

Nomenclature

 *  erinaceus. Cataulacus erinaceus Stitz, 1910: 134, fig. 3 (w.) EQUATORIAL GUINEA. Forel, 1913h: 350 (q.). Material of the nomen nudum princeps referred here: Wheeler, W.M. 1922a: 913. Senior synonym of crassispina: Bolton, 1974a: 52.
 * crassispina. Cataulacus erinaceus var. crassispina Santschi, 1917b: 287 (w.) CONGO. Junior synonym of erinaceus: Bolton, 1974a: 52.

Bolton (1974) - The variety crassispina was founded upon a specimen with rather reddish pilosity, shorter propodeal spines which were rather more elevated than usual, and a shorter pedicel. These characters fall well within the limits of variation established in the present survey. Wheeler (1922a:198) noted under erinaceus that, 'Forel many years ago gave me a specimen labelled "Cataulacus princeps Emery" and has himself referred to it under that name [teste Forel, 1909a] which seems to exist only in manuscript". A specimen loaned by MCZ, Boston, examined during the present survey bears the label -C. princeps Emery. This specimen, as the one referred to by Wheeler, is a very ordinary individual of erinaceus, and as no description of princeps exists it is here included as a nomen nudum.

Worker
Bolton (1974) - TL 8.1 – 9.5, HL 1.90 – 2.34, HW 2.22 – 2.70, CI 115 - 117, EL 0.62 – 0.74, OI 27 - 29, IOD 1.74 – 2.06, SL 1.16 – 1.38, SI 51 - 53, PW 1.90 – 2.40, AL 2.20 – 2.68, MTL 1.40 – 1.62 (10 measured).

Occipital crest absent, the vertex rounding into the occiput. Occipital corners armed with a large, triangular, broad tooth, the sides of the head behind the eyes strongly denticulate. Preocular tooth relatively small, in some cases indistinct. Pronotum marginate laterally, strongly denticulate; the margination expanded, much broader behind than in front and posterolaterally produced into a long, very broadly triangular spine, the edges of which are denticulate. Sides of mesonotum and propodeum weakly marginate, at least in part, the latter with denticles, the former with at least one denticle. Propodeum with a pair of long, acute, tapering spines which are quite broad basally. In profile both the propodeal spines and the posterolateral pronotal spines are seen to be directed somewhat upwards. The angle of elevation of both pairs of spines tends to vary, and in some specimens the propodeal spines may be directed almost vertically. Sutures absent from dorsal alitrunk but the region of the meta notal groove somewhat impressed, shallowly concave in profile, with the promesonotum on a somewhat higher level than the propodeal dorsum. Petiole and postpetiole nodose, the former more massive than the latter. First gastral tergite not marginate laterally.

Sculpturation of entirety of dorsum of head, alitrunk and pedicel of a coarse rugoreticulum with very finely and densely reticulate-punctate interspaces. First gastral tergite similarly sculptured but the rugoreticulum much finer and more dense.

Short, blunt, stout, erect hairs numerous everywhere, arising from the points of junction of the meshes of the rugoreticulum. This is particularly conspicuous upon the pronotal dorsum.

Type Material
Bolton (1974) - Syntype workers, CAMEROUN: Mundame (Conradt); and EQUATORIAL GUINEA: Alen (Tessmann) (MNHU, Berlin) [examined].

Cataulacus erinaceus var. crassispina. Holotype worker, CONGO REPUBLIC: Goda, P. Charleuf (H. de Buysson) (NM, Basle) [examined].

Additional References

 * Yanoviak, S. P., R. Dudley, and M. Kaspari. 2005. Directed aerial descent in canopy ants. Nature. 433:624-626.


 * Yanoviak, S. P., B. L. Fisher, and A. Alonso. 2007. Arboreal ant diversity (Hymenoptera: Formicidae) in a central African forest. African Journal of Ecology. 46:60-66.


 * Yanoviak, S. P., B. L. Fisher, and A. Alonso. 2008. Directed aerial descent behavior in African canopy ants (Hymenoptera: Formicidae). Journal of Insect Behavior. 21:164-171.