Aphaenogaster charesi

An inhabitant of rock walls with humid conditions.

Identification
Salata and Borowiec (2016) - Aphaenogaster charesi belongs to a subgroup of species that occur in the Dodecanese Archipelago. The other species are Aphaenogaster jolantae from Rhodes and Aphaenogaster olympica from Karpathos. The group is identified by the following characters: the head is elongately oval, gradually narrowed posteriorly, without a narrow neck, and with occiput margined by a low, sharp carina; body is colour dark, from pale brown to almost black. Aphaenogaster charesi is (1) the most microsculptured species, with almost the entire surface of the head and the top of the pronotum distinctly microreticulate; and (2) the palest species, with body pale brown and antennae and legs mostly yellowish. In the other two species only the central part of the head between eyes and the top of the pronotum have diffused microreticulation, and the body is darker, from brown to dark brown and antennae and legs mostly brown. Pubescence on the head, scapes and legs in A. charesi are longer and denser and more raised from the surface than in A. jolantae and A. olympica. Also the pubescence of both the ventral and dorsal part of the head in A. charesi is longer and denser than in the other two species. Aphaenogaster charesi has the smallest eyes in the group (EL 0.168–0.201 vs. 0.218–0.257 in A. jolantae and 0.201–0.257 in A. olympica) and it differs from A. jolantae by having distinctly longer scapes (SL: 1.859–1.913 vs. 1.457–1.763, SI1: 133.3–137.1 vs. 122.3–130.4) and from A. olympica by having a distinctly longer petiole (PI1: 202.0–205.8 vs. 134.6–169.4). It also differs from both species in the smaller PPI2 index (30.1–31.2 vs. 33.1–43.6 in A. jolantae and 42.2–50.7 in A. olympica).

Distribution
Greece, Dodecanese, Rhodes island.

Distribution based on Regional Taxon Lists
Palaearctic Region: Greece.

Biology
Salata and Borowiec (2016) - Petaloudes (Valley of the Butterflies) is a mountain valley that is in part a gorge with high rocky walls. It is a well-known tourist attraction inhabited by thousands of the Rhodesian subspecies of the Jersey Tiger Moth (Euplagia quadripunctaria rhodosensis). Following the wet season (late May), individuals of this species seeking high humidity cover the entire landscape in the area. Three specimens of A. charesi were collected on a 6 m high rock wall located in a shady spot near the entrance to the valley. This place was extremely humid because of water dripping down the wall from a small source located in the upper part of the valley. The entrance to the nest was probably located in a rock crevice about 2 m from the bottom of the wall.

Epta Piges (Seven Springs) is a site with several springs and a small lake surrounded by woodland. In one place water from the springs flows through a 150 m long tunnel carved in the rocky soil. Two specimens of A. charesi were collected on the humid, cracked wall about 1 m from the entrance to the tunnel. Similar habitat requirements and locations of entries to nests were also observed for three other species of the cecconii group: Aphaenogaster cecconii on Crete, Aphaenogaster jolantae on Rhodes and Aphaenogaster lykiaensis in Turkey.

Nomenclature

 *  charesi. Aphaenogaster charesi Salata & Borowiec, 2016: 194, figs. 1-5 (w.) GREECE.

Worker
(n=5): HL: 1.386 ± 0.027 (1.36–1.424); TL: 0.696 ± 0.016 (0.676– 0.719); GL: 0.401 ± 0.016 (0.381–0.417); HW: 0.947 ± 0.03 (0.921–0.978); CW: 0.181 ± 0.01 (0.168–0.201); FLW: 0.313 ± 0.014 (0.302–0.335); SL: 1.875 ± 0.02(1.859–1.913); EL: 0.187 ± 0.01 (0.168–0.201); EW: 0.146 ± 0.008 (0.134–0.156); ML: 1.993 ± 0.08 (1.913–2.098); PSL: 0.26 ± 0.01 (0.246–0.279); SDL: 0.198 ± 0.005 (0.19– 0.201); HTL: 1.667 ± 0.04 (1.609–1.717); PL: 0.582 ± 0.02 (0.559–0.594); PPL: 0.361 ± 0.013 (0.346–0.38); PH: 0.280 ± 0.01 (0.257–0.291); PPH: 0.292 ± 0.01 (0.279–0.304); PNW: 0.649 ± 0.02 (0.623–0.682); DPSB: 0.207 ± 0.013 (0.19–0.223); DPST: 0.239 ± 0.026 (0.221–0.285); PW: 0.211 ± 0.009 (0.198–0.223); PPW: 0.286 ± 0.007 (0.277–0.296); HI: 68.3 ± 0.9 (67.2–69.5); CI: 19.1 ± 1.06 (17.9–20.6); FLI: 57.7 ± 2.3 (55.6–60.3); SI1: 135.3 ± 1.6 (133.3–137.1); SI2: 198.0 ± 4.4 (191.8–203.0); PI1: 204.1 ± 1.9 (202.0–205.8); PI2: 61.5 ± 2.09 (59.7–63.8); PPI1: 123.5 ± 1.7 (121.1–125.9); PPI2: 30.8 ± 0.4 (30.1–31.2); SPI1: 27.4 ± 0.7 (26.7–28.5); SPI2: 131.0 ± 6.2 (122.2–138.9); HTI: 176.0 ± 4.0 (172.0–180.4) MI: 307.3 ± 3.7 (303.8–313.3); PSI: 141.6 ± 4.6 (135.0–147.1); TGI: 173.7 ± 7.4 (165.5–181.5).

Head, thorax and abdomen pale brown, base of gaster with slightly paler basal spot, borders of spot indistinct. Legs uniformly yellowish to yellowish-brown. Antennal scapes yellowish brown, pedicle yellowish. Head posterior to eyes gently, regularly convex, without constriction at base, basal margin margined by sharp carina. Anterior margin of clypeus shallowly emarginate. Eyes very small, 0.59 times as long as length of tempora. Scapes elongate and slim, 1.94 times as long as width of head, at base 0.5 times as wide as in apex, gradually widened, mostly straight, only apex slightly bent down without preapical constriction. Funicle elongate and thin, 1.42–1.44 times as long as scape, first segment elongate, 2.4 times as long as wide on apex, 1.29 times as long as second segment, length ratio of segments 100:75:88:88:92:92:104:167:167:163:225, apical segments 1. 5 times as wide as basal segments. Surface of scape finely microreticulate but shiny, covered with short and sparse mostly semierect setae, especially in apical half of scape pubescence distinctly raised from the ground.

Promesonotum 1.87 times as long as wide, pronotum gently convex in profile with very shallow cleft between pronotum and mesonotum. Propodeum elongate, 1.33 times as long as wide, propodeal spines short, needle-like, pointing obliquely upwards. Petiole elongate with long peduncle, anterior face of node deeply concave, node subangulate in profile. Posterior face straight for first 3/4 of anterior length then shallowly concave. Ventral margin of petiole straight, without spine or distinct angulation. In dorsal view, petiole with almost parallel sides anterior to petiolar node, then gently widening. Postpetiole in profile rounded. In dorsal view postpetiole 1.33 times as long as wide, regularly widened from base to apex, apical half with gently rounded sides.

Mandibles elongate, with outer edges straight, dorsal surface with distinct striation and several setose punctures, shiny, masticatory margin with large apical tooth and 6–7 smaller teeth. Entire surface of clypeus with fine irregular rugae, interspaces microreticulate but shiny. Frontal carinae short, not extending to the line connecting anterior margin of eyes, subparallel, interantennal area deeply impressed, shiny, with only one median, fine carina, frontal triangle with thin longitudinal rugae, microreticulate but shiny. Sides of frons with thin longitudinal rugae, center with distinct microsculpture but shiny. Area between eyes finely microreticulate but appears shiny, microreticulation gradually diffused from front to back but well visible on whole surface, gena and tempora with distinct microreticulation, base of head with diffused microreticulation, surface from slightly dull to shiny. Dorsal surface of pronotum completely microreticulate, sides with fine longitudinal striae. Surface of pronotum shiny, sides more or less shiny, with rows of 4+2+4+2 setae. Entire surface of mesonotum microreticulate and partly microgranulate, sides microgranulate with fine rugae. Dorsum of propodeum microreticulate, in anterior part with fine transverse wrinkles, sides slightly granulate, surface below spiracles with few fine longitudinal rugae but surface of both mesonotum and propodeum appears slightly shiny. Anterior portion of mesosomal dorsum with 8 setae, posterior portion with only 2 setae, surface of propodeum between spiracles and propodeal spines with a pair of short setae, slightly shorter than spines, in some specimens additional pair of very short setae present halfway between spiracle and base of propodeal spine. Base of petiole and postpetiole microreticulate but without wrinkles, nodes smooth and shiny, covered with several sparse, long setae. Gaster shiny, basal tergite without or with very short longitudinal grooves but with distinct microreticulation, all tergites with sparse, long, erect setae reaching up to 1.5 times length of propodeal spines. Legs very long, hind femora 1.03 times as long as thorax, hind tibiae 0.75 times as long as hind femora, hind tarsi 1.15 times as long as hind femora. External surface of femora with short sparse pubescence, in basal half appressed, in apical half semierect. Inner margin with row of sparse, moderately long, setae. Tibiae on sides and posterior surfaces covered with short, semierect pubescence; inner, apical margins with row of slightly longer and semierect setae.

Type Material
Holotype (No. LBC-GR01682-HOL) and two paratypes (No. LBC-GR01682-PAR): GREECE, Dodecanese, Rodos Epta Piges, 99 m  36,25459 N / 28,11378 E  4V2015, L. Borowiec Collection L. Borowiec   Formicidae LBC-GR01682 (preserved in Department of Biodiversity and Evolutionary Taxonomy, University of Wrocław, Poland); two paratypes: Greece, Dodecanese, Rodos   Petaloudes, 240 m   36,33567 N / 28,06264 E  8 V 2015, L. Borowiec Collection L. Borowiec Formicidae LBC-GR01747 (preserved in Department of Biodiversity and Evolutionary Taxonomy, University of Wrocław, Poland); one paratype: Greece, Dodecanese, Rodos   Petaloudes, 240 m  36,33567 N /28,06264 E  8 V 2015, L. Borowiec Collection L. Borowiec Formicidae LBC-GR01747 (deposited in Natural History Museum, London, United Kingdom).

Etymology
Named after Chares of Lindos, a Greek sculptor born on the island of Rhodes. Chares constructed the Colossus of Rhodes in 282 BC, one of the Seven Wonders of the Ancient World.

References based on Global Ant Biodiversity Informatics

 * Salata S., and L. Borowiec. 2018. Taxonomic and faunistic notes on Greek ants (Hymenoptera: Formicidae). Annals of the Upper Silesian Museum in Bytom Entomology 27: 1-51.