The Ants of Africa
Contents - Myrmicinae - MYRMICINAE Introduction

Genus Myrmicaria Saunders (1842: 57)

In Tribe MYRMICARIINI. No modern taxonomic revision.

Diagnostic Features - Antennae 7-segmented and indistinctly clubbed. Frontal carinae widely separated. Eyes lie behind the midlength of the head. Anterolateral angles of the pronotum drawn out into a tooth on each side. Promesonotal suture weakly impressed. Mesonotum bluntly bituberculate behind, sharply angled, posterior portion more or less vertical. Metanotal groove deeply impressed, propodeum bispinose. Petiole with a long anterior peduncle. Sting coarse.

Saunders (1842) genus definition (the male of Myrmicaria brunnea) is at {original description} (illustrations unavailable). Arnold (1916: 261) gave a transcription of the genus description with a key to South African species, this is at {original description}.

Most members of the genus are savannah living, nesting in the earth and often making sunken runways. The long petiole peduncle enables the workers to hold the gaster pointing almost directly downwards, which provides a quick diagnostic feature for the genus. Longhurst et al. (1983) examined multi-component alarm pheromones from the poison gland secretion of Myrmicaria eumenoides and M. striata.

Most of the following text is my translation of the Genus definition and species descriptions as given by Dr F. Santschi - Santschi (1925c, Révision des Myrmicaria d' Afrique. Annales de la Societé de Belgique. 64 (1924): 133-176). I have added comments from other authors where appropriate - as [Forel, 1911, etc].

Taxonomic history

The initial studies of this genus were confused by the sexual dimorphism (notably the males have 13-segmented antennae; whereas the workers and females have 7-segmented antennae) resulting in the recognition of the ants into the separately named genera. The first male was described as Myrmicaria brunnea from the Indies by Saunders in 1841. Fifteen years later, Frederick Smith described females and workers of three species Heptacondylus arachnoides, H. subcarinatus and H. carinatus from Borneo, Santschi remarks - no doubt because of their seven-segmented antennae. Finally, a decade later, Mayr established the identity of all the forms as belonging to the single genus, Myrmicaria.

Genus description

In Santschi's words - "It is incontestible that Myrmicaria with its seven-segmented antenna is very aberrant. Such antennal reduction is shared only by the nine-segmented antenna of the fossil genus Ennamerus Mayr, known from Baltic amber. That also is unique and without affiliated genera". He gave the following taxonomic definitions -

Generic characters

Form variable but very feebly dimorphic; the minors with a narrower head and and the antennal funiculi somewhat thicker. All species (sensu strictu) with a dorsal longitudinal median ridge of variable prominence, on the head, pronotum and often on to the mesonotum. Antenna with seven segments of unequal length. Of the funiculus segments, generally the second and last (apical) are the longest; often there is an enlarged club of three longer, stouter segments, sometimes the club is of a single segment. Three-segmented palps. Mandibles with 3 to 5 teeth. Frontal carinae spread, parallel and of medium length. Eyes medium-sized, convex, placed at or behind the mid-length of the head. Without ocelli. Clypeus (epistome) developed and convex. Pronotum dentate or lobed at the inferior angles (the mesokatepisternal tooth). Mesonotum angular, the basal face (anterior dorsum) on the same level as the pronotum and with the declivital (posterior) face penetrating into a strong metanotal groove. Superior angles of the mesonotum bordered, lobed or tuberculate. Propodeum (epinotum) bispinose. Petiole with elongated anterior peduncle. Postpetiole nodiform. Tarsi and antennae elongated. Claws simple. Pilosity usually abundant.

Much bigger and more massive (bulky) than the worker. Thorax large and high. Mesonotum convex and bulged, overlapping almost all the pronotum. Scutum prominent. Propodeum armed. Gaster voluminous with the pedicel stouter than in the worker. Wings with a closed cubital cell and one discoidal. The radial cell is closed and very long, reaching the end of the wing and narrowing gradually.

As long but less robust than the female. Clypeus convex and bulged. Frontal carinae and mandibles very short. Antennae long and with 13 segments. Scape (only) as long as the next two or three segments combined; first funiculus segment very short. Mesonotum with Mayr's groove (?). Petiole and especially the postpetiole more elongated than in the worker. Gaster spike-like, convex dorsally and concave ventrally, with the stipes (?) linear and projecting.

{myrmicaria glossary}

Species descriptions and glossary

Unless indicated, for example as with the descriptions of Wheeler (1922), the species descriptions are my translations of those given (in French) by Santschi. His benchmark species for the descriptions is natalensis and he often refers back to that species in making comparative statements.

NOTE - In translating the French, I have used the terms as follows:- arêtes = ridge, edge or flange; arrondi = rounded; atténué = attenutated (less extreme); clair = pale; comprimé = compressed; dressée = raised; effacée = faint (eroded); épais = thick (wide); épinotum = epinotum, modern usage = propodeum; épistome = clypeus ; inermes = rounded, i.e. not a distinct spine; lisses = smooth, polished; rides = rugae (wrinkles), hence rideé = rugose, and ride = ridge; roux = reddish-brown (russet); taille = form (literal translation - figure, cutting, etc. - apparently applied to tailoring); trapue = thick-set (stocky) in build or appearance; dépasse de moitié (plus grand de moitié) = half as big, long again.

Key to workers of African species

Contents MYRMICINAE Introduction
© 2007, 2008, 2012, 2016 - Brian Taylor CBiol FRSB FRES
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