Introduction

The Ants of Africa Chapter 2 - Geography and History - Guinea

Summary of known collectors
M W Adam (Santschi, 1939f); Andrieu (Santschi, 1930a); R Buchholz (Mayr, 1902); T Humle (Taylor, 2005w); Dr Imhoff (Roger, 1861a); Maxime Lamotte (Bernard, 1952); Marchand (Santschi, 1910g); H Pobeguin (Santschi, 1923e); F Silvestri (Santschi, 1914d, 1915c, 1930a); A Villiers (Bernard, 1952). Note: Marcus Stüben has told me (September 2009) that Isert (Paul Erdmann Isert), who often is listed from Fabricius (1793) as collecting in "Guinea" (and was by me also until now) actually collected in "Danish Guinea" = Gold Coast = modern Ghana.

Most of the collecting areas are shown on Map 9

As for so many countries, an early collector was Professor F. Silvestri, in 1913, collecting at Mamou (10°20'N, 12°15'W)(Cataulacus tardus and Leptogenys guineensis); Camayenne near Conakry (9°25'N, 13°40'W) (Tetramorium anxium); and Conakry, on 8.viii.1913 (Leptogenys crustosa) (all in Santschi, 1914d). He also collected Paedalgus infimus at Kindia (10°N, 12°45'W) (as Oligomyrmex infimus, Santschi, 1913e) and Technomyrmex moerens at Mt. Kakoulima (9°40'N, 13°25'W, in Wheeler, 1922). Polyrhachis decemdentata was collected by H. Brauns from Los Islands (9°30'N, 13°50'W) (Wheeler, 1922). Santschi (1939f) reported collections made by M. W. Adam, while on the exploration cruise of the Belgian vessel Mercator whilst off West Africa in late 1935. The main locations were at Conakry and on the Los Islands just off Conakry, 20-24 November.

Reading the English language literature gives no hint of the magnitude of the work undertaken and reported by Francis Bernard (Bernard, 1952). He related how Th. Monod, Director of the "Institute français d'Afrique Noire" (IFAN; Afrique Noire being equivalent in modern terms to sub-Saharan Africa), assigned a number of geographers and naturalists to study the Mount Nimba Forest Reserve. This forested massif, some 50 km long by 12 km wide, with Mont Nuon as its highest point at 1752 m, is in the extreme south of the country, forming an upland area almost encircled by Liberia and Ivory Coast, and was the main remaining rain forest area. In respect of ants, the major zoologist was Maxime Lamotte, who collected from January to June 1942 and July to September 1946. In September 1946, the work was complemented by the efforts of A. Villiers. Both collected all sorts of animals, with Lamotte's efforts yielding 90% of the specimens, although the 10% collected by Villiers from sifting the "mousses en forêt" (which I translate as leaf litter rather than the literal "moss") rounded off the work. Bernard himself was at the Faculty of Science in Algiers and had already done other taxonomic work on ants of the Sahara, especially Fezzân.

As a simple bench mark of the Mt. Nimba study, Bernard, who did all the taxonomic work, reckoned that a total of 193 species, of which 54 were new, and 53 genera, 3 being new, were separable. At that time, only three comparable efforts had been made in sub-Saharan Africa - the continuing work by Arnold work in Rhodesia and South Africa, from 1906 on (until around 1960); the 1920 Belgian Congo study by Lang and Chapin (see the notes on Zaïre); and, the 1939 survey of Mount Imatong in southern Sudan, by N.A. Weber in 1939. The Nimba study, moreover, involved altitudinal studies, otherwise done only on Mt. Imatong. Bernard described examining the museum collections in France and, on finding those inadequate, examining all the material in the Swiss museums in Basle and Geneva, originally worked on by Forel and Santschi. The results of his taxonomic efforts are incorporated in the Catalogue sections.

Together with, Lamotte, Bernard made an analysis of the biogeography and ecological findings. As these have been given little attention in the English literature, an extensive translation and précis can be found in the Chapter on Diversity and Habitats. They also provided a summarised description of the massif and, translated, this is as follows:

The massif is formed of silicaeous rocks - granites, gneisss and quartzites - and, because only the last is resistant to erosion, has steep slopes between 900 and 1700 m. Ravines are found in the softer rocks and all the villages are placed where watered places occur on the granite. At that time, some 3000 people lived on the massif, cultivating rice and manioc (cassava). Well conserved primary forest clothed almost half of the region. Areas between 450 and 900 m were made up of savanna and cleared forest in dicontinuous patches. From 1100 to 1700 m the slopes and crests were denuded, with low montane grassland ("prairies"), where the dominant plant was the grass, Loudetia kagerensis. Climatically, the massif was considered to be subequatorial, as a whole receiving some 1500 mm to 3000 mm of annual rainfall, most falling from late March to September.. The highest rainfall was on the summits. The very steep slopes towards the south-east fall some 1200 m to the Ivory Coast plains and receive more rain than the north-eastern aspects, in Guinea, which have only 1500 mm to 2000 mm annually. Savanna areas are burnt each March and their fauna is particularly affected by the amount of rain. When the latter is heavy and humidity is high, trees and tall grasses occur, provided that the roots can spread through the soil. Where the soil is lateritic and lacking depth, one finds the impoverished savanna (such as at Sérengbara). Much more stable is the primary forest where, at 1000 m, temperature extremes are 19° to 23.5°C. It alone is a land of dense humus. Through the scrub of the crest, one passes from forest to montane grassland, where temperature ranges from 12° to 27°C in the dry season to 18° to 22°C in the wet season. Two thirds of the vegetation layer is made up of rotting matter, with a unique fauna. Especially notable, in an area with no ponds or streams, is an endemic, small, viviparous toad, Nectophrynoides occidentalis.

The actual localities at which collections were made represented three ecological zones:-

Savanna - 500-900 m.

Kéoulenta - at 500-550 m, on the east of the massif, quite moist, with reasonable soil and large Andropogon grass.

Sérengbara - at 590 m, and to the west, with impoverished lateritic soil, low grasses (Cyperaceae) and high soil temperatures in the dry season.

Ziéla - to the east, at lower altitude and with many more trees.

Forests - seven stations, 450-1300 m, all differing.

Yalanzou - dense forest, 25 km west of the foot of the massif.

N'Zo - the driest forest, 480-500 m.

Nion - station 22, at 700 m ; cleared secondary forest, on the crest.

The Villiers collection area, at 700-900 m, on the North-east slopes of the massif.

Camp IV - rich, heavily wooded, primary forest above Nion, at 950-1000 m.

Zouépo - station B 8-10, at 1250 m, at the highest limit of forest.

Ravin I of Mount Tô - 110-1600 m; a large fault split in a less sloping face, falling eastwards to Ziéla; with less shaded soil than the above locations.

The crest of Nion - at 1300 m, scrub rather than pure forest, with dense fogs, some montane grassland areas.

Montane grassland subject to frequent fog or mist and with low grasses and relatively deep black humus-rich soil.

Camp I - at 1600 m, with named stations being F (at 1400 m) and F32 (at 1550 m), very well surveyed by Lamotte, with many rocks, the presence or absence of which determined the ant species. Notable also for a lack of termite mounds.

Other collections came from G'ba in lower Guinea (including by A. Balachowsky).

Orthoptera collections by Lamotte, together with Amiet and Vanderplaetsen, who also worked in the group in 1957, were reported by Ragge (1980).

In the last few years, a group of anthropologists have been studying the behaviour of chimpanzees at Bossou in the southeastern region of Guinea (7°39'N and 8°30'W), about 6 km west of the foot of the Nimba Mountains on the border with Côte d'Ivoire and Liberia. Bossou was established as a chimpanzee field site in 1976 and among the studies has been an investigation into the use of tools for "ant-dipping", notably for Driver Ants (Dorylus (Anomma) species). Tatyana Humle, of the University of Stirling, is a current researcher and she asked me to identify ants from 13 samples. The results are in the Anomma section of the catalogue. Apart from Bossou, specimens came from Seringbara (Sélinnbala) at 7°37'53"N and 8°28'01"W), slightly closer to Mount Nimba; and Yéalé, across the border in Ivory Coast (at 7°32'00"N and 8°24'49"W). A description of the area, borrowed from the Bossou project website at http://www.pri.kyoto-u.ac.jp/chimp/Bossou/Nimbaetc.html is on the linked page.

©1998-9, 2002, 2003, 2006, 2009, 2012 - Brian Taylor CBiol FSB FRES 11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.

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