The Ants of Africa

	The Ants of Africa SUBFAMILY FORMICINAE - Genus Paratrechina
Contents - Formicinae - FORMICINAE Introduction

Genus Paratrechina Motschulsky (1863: 13)

In Tribe LASIINI, previously PRENOLEPIDINI.

Diagnostic Features - Dorsal surface of head, alitrunk and gaster with distinctly paired coarse hairs. Eyes well developed and set at or in front of the mid-length of the head. No ocelli. Antennae 12-segmented and inserted close to the posterior margin of the clypeus. Anterior clypeal margin entire or weakly emarginate medially. Mandibles narrow, with five or six teeth. Palpi long. Propodeum unarmed. Petiole a reduced scale inclined forwards and often overhung by the first gastral segment, always unarmed above. Acidopore borne on a conical projection of the hypopigium, and surrounded by a fringe of hairs.

Motschoulsky's (1863) genus definition is at .

From Africa most species were regarded as in the subgenus Nylanderia Emery (1906b: 133; as a subgenus of Prenolepis; subgenus of Paratrechina, Emery, 1925b: 217). Emery (1925b) transferred a number of species from Prenolepis to Paratrechina, including all those known from Africa. The definition of Nylanderia (Emery, 1906b: 133 ) was that the alitrunk is not significantly narrowed in the mesothorax region nor swollen to the anterior or posterior of that region; also scapes and tibiae covered with short pubescence and in many cases with sparse erect or semierect simple hairs. That separation, however, was as a subgenus from a group of species in the genus Prenolepis. James Trager (e-mail, i.2005) has assured me, from his extensive review (Trager, 1984b: 51), that there is no merit in separating Nylanderia as a subgenus within Paratrechina.

Bernard (1952) writing of the Tribe LASIINI, described these as small, very specialised, terricolous ants, showing polymorphism. The larvae have a reduced buccal apparatus and are fed on alimentary fluids, notably the exudate of Homoptera, which the ant workers often raise in the nest. Most have a vast geographic distribution.

Wheeler (1922: 942) listed Paratrechina vividula (Nylander, 1847: 900) as tropicopolitan and gave a single African finding as from Zaïre, at Niapu, collected by Lang & Chapin. This seems exceptional and I have not included it among the African species but it is on Paratrechina vividula from Egypt.

Provisional key to workers from Africa - based primarily on historic descriptions.

¤	Sexual forms only known, although Forel (1916: 440) suggested that the workers he described as grisoni actually might be the asexual form of waelbroecki	Zaïre - waelbroecki
1	Small, TL ca 1.5 mm or less; alitrunk with four pairs of quite stout longish erect stout hairs	2
--	Larger, TL ca 2.0 mm or more; alitrunk usually with quite numerous more slender erect hairs	4
2	TL 1.3 mm; shiny yellow-orange; head rectangular with near straight anterior margin; scapes slender and just surpassing the occiput	Nigeria - undet species T¹
	Head ovoid, darker colour	3
3	TL 1.3 mm; brown, near black, dorsum of alitrunk and gaster lighter; tarsi, mandibles and petiole pale; matt; with distinct pruinose pubescence; scapes exceeding occiput by about 1/3 of their length; propodeum profile an acute angle with the dorsum much shorter than the declivity	West Africa & Congo Basin - albipes
--	TL 1.5 mm; brown-yellow; submatt; scapes exceeding occiput by about 1/4 of their length; with corase short pubescence giving a shaggy appearance; erect hairs long, yellow, thickish, 4 pairs on the alitrunk	.
.		West Africa & Congo Basin - subtilis
4	Larger TL > 2.5 mm	5
--	Medium TL ca 2 mm	8
5	TL 2.5-3.0 mm, very slender with elongated legs and antennae; pale smoky brown with paler appendages; erect hairs long and blunt	Pantropical tramp - longicornis
--	Not obviously elongated nor very slender	6
6	TL 3.6-4.0 mm; mandibles matt and very densely striated, clypeus carinate and strongly vaulted, large eyes in posterior third of face, scape surpassing occipitum by about one-third its own length; red brown, legs and antennae reddish-yellow; overall matt and densely reticulate-punctate all over; erect hairs large and pointed but generally scarce	Zaïre - kohli
--	TL < 3.5 mm	7
7	TL 2.5-3.0 mm; clypeus without carina, eyes forward of mid-line of face; head, pronotum and propodeal declivity shining, gaster superficially rugulose and quite dull; pilosity coarse dark-brown, pointed not blunt; head and gaster brown, alitrunk and appendages brown ochre	Sudan, Congo and South Africa - traegaordhi
--	TL 2.8-3.1 mm; shiny except for propodeum which is finely puncturate on dorsum and sides; strong erect brown pilosity all over; head and alitrunk brown, gaster near black	Guinea & Ghana - arlesi
--	TL 2.5-3.0 mm; clypeus quite strongly scalloped; eye oval longer than wide; propodeum with dorsum shorter than declivity; whole body with obtuse, quite coarse erect dark brown hairs; abundant pubescence; dark brown to blackish; mandibles reddish brown, legs and antennae dark brown	pantropical tramp (Pemba Is., Tanzania) - bourbonica
--	Medium sized TL > 2.5 mm	--
8	Colour generally pale, testaceous yellow, parts may be darker; with fine pilosity; head in full face view with relatively straight sides	9
--	Darker at least red-brown; head in full face view with convex sides	10
9	TL 2.2 mm; matt, head a little shiny; colour generally pale, testaceous yellow; propodeum with short dorsum and much longer near vertical declivity, transition angular; erect pilosity long, fine and yellow	Congo Basin - weissi
--	TL 2.2-2.6 mm; HL > HW; somewhat darker yellow-brown;	Egypt - jaegerskioeldi
--	TL ca 2.5 mm; HW = HL = SL; generally brown, alitrunk lighter	West Africa - nimba
10	TL ca 2.2 mm; scape surpasses occiput by more than half its length; colour red-brown, shiny; head ovoid with near straight occiput	São Thomé - incallida
--	Darker	11
11	TL 2.2 mm; uniform shiny brown, propodeum a fairly smooth curve, head with convex sides	East Africa, Congo & Nigeria - zelotypa
--	Darker, propodeum notably humped	11
12	TL ca 2 mm; propodeum very humped, with small tooth at base of declivity; dark brown, shiny;	West Africa & Congo Basin - grisoni
--	Propodeum not so grossly humped and without tooth at base of declivity (lepida profile)	13
13	TL ca 2.0 mm; antennal scape surpassing occiput by some 1/3 of its length; head smooth & shiny; black with a brown tint; bristly	Cameroun & Congo - lepida
--	TL ca 2.0 mm; antennal scape surpassing occiput by about 1/5 of its length; head finely striato-reticulate; black, appendages brown, palps & taris whitish	Fernando Po I. - mendica

Undetermined species

Paratrechina species (indet.) (1)

Described as widespread, 794 workers from 12 sites, in Ghana semi-deciduous forest leaf litter by Belshaw & Bolton (1994b).

Paratrechina species (indet.) (2)

Forty-eight workers found in secondary forest leaf litter at five sites, plus under cocoa at Bunso, in the Ghana semi-deciduous forest, by Belshaw & Bolton (1994b).

Paratrechina species (indet.) (3)

Many (148) workers found in leaf litter under cocoa at Effiduase, Asiakwa and Nankasi, and under forest at Bobiri, Ghana, by Belshaw & Bolton (1994b).

Paratrechina species (indet.) (4)

A single worker was found in cocoa leaf litter at Asiakwa, Ghana, by Belshaw & Bolton (1994b).

Paratrechina species 4

Found in Ghana, in dead wood on the ground and on herbs under cocoa at the Mampong Cemetery farm, and nesting in the dead wood (Room, 1971). Ten workers were collected from the ground at CRIG by Bigger (1981a).

Paratrechina species

Listed from Ghana cocoa at Kade by Majer (1975).

Paratrechina species 56

From Ghana on cocoa mistletoe (Room, 1975).

Paratrechina species from Campo Forest

From Cameroun, Campo Forest trees (Campo forest survey, 1991). Nests under bark and in epiphyte axils (Dejean & colleagues).

Subfamily Formicinae

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