Polyrhachis revoili species-group

The species in this group are members of the subgenus Myrma.

Species

 * Polyrhachis aenescens
 * Polyrhachis braxa
 * Polyrhachis brevipilosa
 * Polyrhachis dubia
 * Polyrhachis khepra
 * Polyrhachis kohli
 * Polyrhachis lanuginosa
 * Polyrhachis longiseta
 * Polyrhachis luteipes
 * Polyrhachis otleti
 * Polyrhachis platyomma
 * Polyrhachis regesa
 * Polyrhachis revoili
 * Polyrhachis submarginata
 * Polyrhachis terminata
 * Polyrhachis transiens
 * Polyrhachis volkarti
 * Polyrhachis weissi

Identification
Bolton (1973) - Characterised by the partial or total loss of the margination of the alitrunk, the reduction or disappearence of the dorsal sutures of the alitrunk, and a tendency towards the reduction of sculpturation. All species in the group except Polyrhachis aenescens have abundant long, erect hairs on all dorsal surfaces of the head and body, and a majority have long hairs on the appendages also.

This group is considered to have developed from the viscosa group. In the important character of the loss of margination of the alitrunk a number of species are known which are intermediate between the groups of viscosa and revoili. The transition from a fully marginate to a completely immarginate condition is illustrated by the following series of species: Polyrhachis durbanensis → Polyrhachis transiens → Polyrhachis aenescens → Polyrhachis otleti → Polyrhachis regesa → Polyrhachis revoili. In the first species, a member of the viscosa group, the alitrunk has complete margination. The second species shows complete margination of the pronotum whilst the mesonotum and propodeum are very weakly and obtusely margined, the latter more weakly so than the former. The propodeal margination is lost in aenescens, and in otleti only the pronotum retains margins. In regesa the pronotal margination is weak and only extends for part of the length of the segment. No trace of margination remains in the last species of the series.

The dorsal sutures of the alitrunk are very much reduced, especially the metanotal groove. Apart from Polyrhachis platyomma in which it is distinct, the groove is represented in most species only by a very faint line which may fail to break the sculpturation in places. In Polyrhachis volkarti the metanotal groove is completely absent, and in Polyrhachis khepra both dorsal sutures are supressed. The pronotal spines decrease in size as one moves away from the species most similar to those in the viscosa-group and the intensity of sculpturation lessens, until in Polyrhachis braxa the spines are represented by a pair of very small teeth and the integument is smooth and highly polished. In most species the sculpturation is similar to that found in the viscosa group, that is, reticulate-punctate overlaid by rugulation or a rugoreticulum.

Propodeal armament is variable; in some species a pair of upcurved teeth are present but in others these are reduced to tubercles or are entirely absent. A modification found in some species of the group is the development of transverse propodeal ridges which separate the dorsum from the declivity. In all species where these ridges are present they are incomplete medially, with a small but distinct gap between them.

The petiole follows the pattern described for the militaris complex, the majority of species having a pair of long dorsal spines with a smaller lateral pair. The latter tend to be diminished in size in certain species and only a pair of minute teeth or tubercles remain in species such as Polyrhachis lanuginosa and Polyrhachis khepra.

Related Pages

 * Polyrhachis
 * subgenus Myrma
 * Key to Afrotropical Polyrhachis species-groups
 * Key to Afrotropical Polyrhachis species