Aphaenogaster melitensis

Specimens were found under stones in dry habitats. The workers forage singly during daytime. Alate gynes were observed to emerge singly during late morning in September (Schembri & Collingwood 1981; Boer, 2013).

Identification
A member of the A. testaceopilosa group. Boer (2013) - Workers. The setosity is as short as in Aphaenogaster balcanicoides and Aphaenogaster karpathica. Differs from those species by a higher petiole (RPH-mean 148) in relation to the width (other species < 141), significant in A. balcanicoides and A. karpathica (p < 0.01). Propodeal spines in general horizontal and slightly splayed. SPL/SPD-mean 1.3, in the other species: 2.9 (balcanicoides), 2.7 (Aphaenogaster balcanica) and 2.4 (karpathica), significant in A. balcanica and A. balcanicoides (p < 0.01) and A. karpathica (p < 0.02). The only gyne observed resembles the one observed gyne of A. balcanica. The biometrical differences are probably lying within normal range. The punctation of the A. melitensis gyne is weaker on the mesosoma and petioles. Males unknown.


 * Key to European Aphaenogaster workers

Distribution based on Regional Taxon Lists
Palaearctic Region: Malta.

Nomenclature

 *  melitensis. Aphaenogaster semipolita var. melitensis Santschi, 1933c: 390 (w.) MALTA. [First available use of Aphaenogaster testaceopilosa subsp. semipolita var. melitensis Emery, 1924b: 12; unavailable name.] Junior synonym of ionia: Bolton, 1995b: 71. Revived from synonymy and raised to species, and senior synonym of ionia: Boer, 2013: 68.
 * ionia. Aphaenogaster semipolita subsp. ionia Baroni Urbani, 1968b: 422, figs. 10, 12 (w.) ITALY. Junior primary homonym and synonym of ionia Santschi: Bolton, 1995b: 70. Junior synonym of melitensis: Boer, 2013: 68.

Description
Boer (2013):

Worker
Rugulose sculpture on dorsal side of pronotum. Dorsal side of petiolar nodes rugulose and punctate. Terminal side of propodeum, beneath the propodeal spines costulate. Lateral sides of petioles wax glossy. Setosity relatively short: setae on anterior side of fore coxa and pronotum much longer than that on head, mesonotum and propodeum. Setosity on lateral sides of head, shorter than maximum scape diameter. Petioles relatively setose. Petiole with rounded top, anterior side steeper than posterior side.

Measurements (n = 32). CI 73–82 (74); CL 1.33–1.66 (1.52) mm; CW 1.05–1.32 (1.17) mm; PHI 28–37 (32); PI 69–86 (76); PPPI 48–55 (51); PSI 145–195 (175); PSLWI 93–142 (116); PWI 20–32 (24); RPH 124–168 (148); RPSI 35–67 (49); SI 142–159 (149); SI/CI 174–215 (193); SL 1.55–1.91 (1.75) mm; SPD 1–3 (1.8); SPL 1–5 (2.0).

Queen
Longitudinal rugulae on clypeus, on some parts of mesoscutum and scutellum. Head anterior to the occiput with longitudinal rugulae and cross-connections, occiput with transverse rugulae. Transverse rugulae on anterior side of pronotum, dorsal side of propodeum and some parts of mesoscutum. Lateral sides of propodeum with longitudinal rugulae, lateral sides of pronotum ruguloreticulated. Mesopleura strigulate. Distal side of petiole and postpetiole scabriculous. Base of gastral tergite with approximately ten circular rugulae. Terminal side of propodeum, beneath the propodeal spines rugulose, glossy. Punctation distinct on head, weak to very weak on the mesosoma and petioles. First gastral tergite dorsally completely microstriated. Anterior side of petiole smooth. Mesosoma matt glossy, gaster dorsally satin. Antennal club 4-segmented. Scape longitudinally rugulose. Scutellum rises distinctly above mesoscutum and bends almost entirely over metanotum. Setae on the lateral sides of the head shorter than the maximum scape diameter.

Measurements (n = 1). CI 92; CL 1.72 mm; CW 1.59 mm; OCI 31; PHI 44; PI 78; PPPI 68; PSI 188; PSLWI 120; PWI 28; RPH 143; RPSI 56; SI 110; SI/CI 120; SL 1.75 mm; SPD 1; SPL 4.

References based on Global Ant Biodiversity Informatics

 * Boer P. 2013. Revision of the European ants of the Aphaenogaster testaceopilosa-group (Hymenoptera: Formicidae). Tijdschrift voor Entomologie 156: 57-93.
 * Emery, C.. "Alcune formiche di Malta." Bollettino della Società Entomologica Italiana 56 (1924): 11-12.
 * Gomez K. 2017. Two species of exotic ants (Hymenoptera: Formicidae) new to Malta. Boletin de la Sociedad Entomologica Aragonesa (S.E.A.) 61: 233-235.