Polyrhachis alexisi species-group

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

Species

Identification

Bolton (1973) - The medium sized to small species making up this group are easily recognized by their very short, broad and deep alitrunks. The pronotum is always marginate, at least for part of its length, but the mesonotum, propodeum, or both, may lack margination. On the head the anterior clypeal margin is equipped with a shallow, rectangular lobe which terminates laterally in a pair of acute, dentiform angles or is flanked by a pair of small teeth. The eyes are usually situated high up on the sides of the head, usually not breaking the outline of the sides in full-face view.

The promesonotal suture is invariably present but the metanotal groove is reduced to a faint line or is absent. Propodeal margination varies from fully marginate both laterally and posteriorly as in Polyrhachis latharis and Polyrhachis limitis to a situation in which the propodeum is totally without margination, as in Polyrhachis curta and Polyrhachis alexisi. Another species, Polyrhachis lestoni, seems to occupy an intermediate position as the lateral propodeal marginations are missing whilst the posterior is present. In all species the propodeum is unarmed, there being no trace of spines or teeth.

The petiole is equipped with two or four teeth or spines in the various species but the basic shape of the segment is a thick, high scale with an acute dorsal margin and with four spines, of which the dorsals are longer than the laterals. Away from this, the most common form, one has on the one hand lestoni which retains only the lateral armament of the petiole as a pair of teeth, and on the other hand curta which has retained only the dorsal pair as two long hooks. Erect hairs are usually absent except on the anterior clypeal margin and the gastral apex, but in some species a few may be present on the dorsum of the head.

Notes

Bolton (1973) - The affinities of this small group are not immediately apparent. No intermediate forms are known but a derivation from the militaris group is suspected because of the structure of the alitrunk and petiole. All species are arboreal, and their distribution is limited to the rain forests of West and Central Africa.

Related Pages

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

References