Crematogaster (Atopogyne) depressa (Latreille)

Type location Guinea (Formica depressa, Latreille, 1802c: 268, illustrated, queen; Forel, 1910f: 5, male, no description), collected from the Coast of Guinea, by Palisot de Beauvois - no type images on Antweb (January 2015)
subspecies
adultera (Crematogaster depressa Latr. var. adultera n. var., Santschi, 1915c: 252, worker) from Congo, Brazzaville, by A. Weiss - overall colour yellow-brown, may be a distinct species - see linked page
fuscipennis (Crematogaster depressa Latr., var. fuscipennis n. var., Emery, 1899e: 479, worker & queen; Forel, 1909b: 53, male, no description; Santschi, 1910c, illustrated) from Cameroun (no details) - see below
junior synonyms
platygnatha (Formica platygnatha nov.sp., Roger, 1863a: 168, queen, with its junior synonym mandibularis (Cremastogaster mandibularis nov. sp., André, 1889: 229, queen) from Sierra Leone - no type images on Antweb (January 2015)
(see Bolton, 1995) .

Note: C. buchneri For. subspec. foreli. nov. subspec., Mayr, 1895: 138, worker, from "Slave Coast" - Guinea; has had various statuses and was synonymized by Bolton, 1995: 153) is reverted here to Crematogaster buchneri.

Latreille's (1802c) description of the queen is at . Roger's (1863a) description of platygnatha is at . André's (1889) description of the mandibularis queen is at . Emery (1899e) provided a drawing of the head of the major and the variety fuscipennis (left). His description of the latter is at .

Santschi (1910c) in a comparison with Cr. julienni had the drawing of the pedicel and mandible (right). He also commented on fuscipennis and described an ergatogyne worker - at (note the illustration clearly was wrongly labelled, the mandible 8e seems to be that of the female shown in 9b; 8c is the mandible of Cr. (Oxygyne) margaritae).

Santschi's (1915c) description of the dark brown adultera is at . Two workers of what appear to be this form from Congo are shown at the bottom of this page.  They have much more pronounced hairs and generally more abundant erect pildsity and pubescence.

Nigeria specimens (Taylor, 1979: 39) WORKER. Size very variable TL 3.42-7.28 mm; largest HL 2.02, HW 1.80, SL 1.18, PW 1.00
Colour dark chestnut brown. Dense pilosity, few erect hairs and only four on the postpetiole. Mandible of largest worker with a concave masticatory margin. Alitrunk profile rounded except in the metanotal groove area where it is often raised. Mesonotal carina low. Propodeal spines acute fairly stout and straight, down curved on the largest workers.

Wheeler (1922) included records from Senegal, Guinea (Los Islands), Sierra Leone (Mocquerys), Ghana, Nigeria (Lagos, Olokemeji and Ibadan, by F. Silvestri; Old Calabar, by H. Brauns), Cameroun (Victoria), plus Congo areas. Santschi (1935) noted a specimen of fuscipennis from Kisantu, Zaïre, collected by R.P. Vanderijst, i.1919. Forel (1909b, 1911f) reported Zaïre specimens - foreli from Luki, by Dr Jullien, fuscipennis from Kinshasa [Leopoldville] by Waelbroeck and Dr Dubois, and "Congo" by Deleval.

From Guinea, Bernard (1952) described it as of the western plains, on Mount Nimba found solely at Kéoulenta and Yalanzou.

A common dominant species, constructing large carton nests on major forest tree (see illustration from Wheeler, 1922, and "click", below left). Forages widely from the nest site onto cocoa and any other adjacent trees.

In cocoa surveys in Nigeria (where it was not separated from Cr. africana) it was found on 10-12% of trees, throughout the cocoa growing area (Taylor, 1977; Taylor & Adedoyin, 1978). Earlier from CRIN, by Booker (perhaps on >10% of cocoa in collections from two cocoa blocks, W13/2 and W18/1, Booker 1968).

In Ghana, Strickland (1951a) found that at CRIG what he describes as the depressa-buchneri group was more common (218 collections) than africana (27 collections) but less so than striatula (778 collections). Bolton (1970-71) listed it as one of the six most common carton-nesting Crematogaster species on cocoa (simply at CRIG or in Ghana is not clear) and noted that it was a common species. Leston (1973) also regarded it as a dominant. It was found in only one cocoa canopy sample by Room (1971) but Majer found it in 13.2% of his 144 pkd samples at Kade, with 300-400 workers per sample (1975, 1976a, b, c). Bigger (1981a) lists a number of cocoa surveys and these have little depressa other than at Kade (Majer's results). However, it since has been described as widespread by Belshaw & Bolton (1994b), who found it, as a 'tourist', in leaf litter samples at six locations in the semi-deciduous forest zone.

Strickland (1951a) added that the depressa-buchneri group was essentially African, from Ivory Coast east to the equatorial forests of Sudan.

In Cameroun it was by far the most common species in the Campo forest canopy surveyed by Alain Dejean and colleagues. It occupied 87.4% of the trees and 85% of the vines, and its colonies reached several million workers. They felt the large ecological success of Cr. depressa is probably due to its ability to nest on trees with or without extra-floral nectaries (EFN).

The photomontage of a worker from the fuscipennis type collection is collated from http://www.antweb.org/specimen.do?name=casent0904471.

Oxford University Museum specimens

The photomontage is of a major worker from Cameroun; collectors McKey Wolbachia project (Cameroon 06).

The photomontage is of a major worker from Benin, Agonlin; collector J-F Vayssieres (RVA 301).

The photomontage is of a media 1 worker from Benin (RVA 301).

The photomontage is of a media 2 worker from Benin (RVA 301).

The photomontage is of a minima worker from Benin (RVA 301).