Aphaenogaster testaceopilosa group

A European group of 14 species, these species were revised in: Boer, P. 2013. Revision of the European ants of the Aphaenogaster testaceopilosa-group (Hymenoptera: Formicidae). Tijdschrift voor Entomologie 156, 57–93. PDF

Species

European species

Introduction

The distribution of the A. testaceopilosa-group in Europe corresponds to the area south of the 20° July isotherm, roughly equal to that part of Europe influenced by the Mediterranean climate, i.e. mild, rainy winters and hot, dry summers. This explains the absence of the subgenus in countries like Ukraine, Bulgaria and Romania (Atanassov & Dlussky 1992, Markó et al. 2006, Radchenko 2011), the more inland countries like Serbia (Petrov 2011), as well as the more inland departments of France (Cagniant & Galkowski 2011).

Only three species are more widespread: A. senilis (North Africa, Iberian Peninsula, southern France, and, most remarkably, Slovakia), A. spinosa (Corsica, Sardinia and from northern Italy to the southern flanks of the Alps in Switzerland) and A. balcanica (from Bosnia to the Anatolian part of Turkey and perhaps further beyond).

It is however noteworthy that at least eight of the fourteen species of the A. testaceopilosa-group exhibit a distribution that can be traced back to the geological history of their range and are still limited to this area. The explanation lies perhaps in the absence of or limited nuptial flights in gyne and the usual dispersal by nest budding (Baroni Urbani 1966).

The scarce material I have seen from Algeria and Tunisia concerns species which are different from the European species, except for A. gemella and A. senilis. The other North-African species of the Aphaenogaster testaceopilosa-group described by Cagniant (1990b, 1996), Santschi (1929, 1933) and Mohamed et al. (2001) do not match the European species.

Diagnostic characters

The worker of the A. testaceopilosa-group have a punctate head and mesosoma, while the head is neither elongated, nor collar-shaped. This character combination is absent in the other European species of the genus Aphaenogaster, except for A. sardoa. The punctation is also present in the gyne and male, but only on certain body parts, usually the head. In most species, the anterior portion of the dorsal side of the first gasteral tergite is microstriated.

Worker

Head, mesosoma and scape largely rugulose, sometimes partially with longitudinal rugulae. Head in full-face view partially ruguloreticulated. Frons longitudinally costulate. Punctation present on head and mesosoma, weaker on lateral side of temple and ventral side of head: more microreticulated. Microreticulation on petioles and legs, the legs often nearly smooth. Terminal end of scape somewhat swollen with distinct or weak longitudinal rugulae, without or with scarce oblique connections. Dorsal side of first gastral tergite largely, sometimes partly, with microstriae in a fingerprint-like pattern, sometimes lacking (spinosa, semipolita), usually posteriorly weakening. Bristle-like setae, regularly spaced, appressed to suberect, sharply pointed to rarely blunt; distance between the setae on the mesosoma always lesser than the length of the setae. Pubescence on head, thorax and gaster is very scarce, less than 10% of the total body setae. Tibiae and femora on all sides with pubescence. Basal margin of the mandibles slightly and unequally bluntly serrulate. Masticatory margin of mandible with 2 or 3 large apical teeth of decreasing length, the remaining part of the margin with blunt teeth and denticles of different sizes. Mandibular sculpture composed of regular costulae. Anterior margin of clypeus broad, usually weakly emarginated. Femur of the hind leg 1.2–1.4× longer than tibia. Length of first tarsal segment of the hind leg 0.9× length of tibia. Tarsal claws simple. Tarsal spurs of hind tibia simple or minutely dentate. Monomorphic.

Queen

Differences compared to the worker caste: Sculpture more costate than rugulose, but more expressed than in workers, while punctation is weaker. Head wider than maximum mesonotal width. First gastral tergite dorsally microstriated.

Male

Mandibles smooth and mostly shiny. Masticatory margin of mandibles in all males with an apical tooth usually twice as large as tooth two, the other teeth are variable. Left and right mandible margins are often asymmetric. Total number of teeth is around 6, number of teeth per mandible may be different in individual specimens. Majority of the teeth are minute, sharp or blunt. Anterior margin of mandible very slightly crenated or straight. Head narrower than maximum pronotal width. Wings with a yellowish to brownish tint (except A. senilis and A. gemella: nearly clear). Sometimes dorsally with longitudinal microstriae on base of gaster. This seems variable in most species. Frontal midline weak or absent, distinct in some specimens of A. picena.

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