Leptogenys Roger, 1861

Yamane, Seiki, Hosoishi, Shingo & Ito, Fuminori, 2024, Taxonomic study on the queens of the Japanese ponerine genera, with a redescription of Ectomomyrmex horni restituted as a valid species (Hymenoptera: Formicidae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 64 (2), pp. 249-267 : 255-256

Leptogenys Roger, 1861

( Figs 2E , 4E , 6E )

Recognition of ergatoid queen. Without wings and ocelli; medium-sized ants, measuring 4.9–5.1 mm in total body length; clypeus strongly and triangularly produced anteriad; mid- and hindtibiae with both simple and longer pectinate spurs; pretarsal claws pectinate.

Description of ergatoid queen. Medium-sized ants, measuring 4.9–5.1 mm in total length and 0.75–0.82 mm in head width in the single Japanese species. Head in full-face view much longer than broad, with straight posterior margin and rounded posterolateral corner of head; head broader posteriorly than anteriorly. Frontal carina short; frontal lobe small. Clypeus strongly and triangularly produced anteriad. Malar space slightly shorter than eye length. Eye large, 0.24 mm in major diameter, its outer margin slightly breaking lateral margin of head, apparently without standing hairs. Ocelli absent. Mandible slender and linear; masticatory margin short with large apical tooth and several small teeth; basal margin long, 3 times as long as masticatory margin, weakly curved, without denticles; outer and basal margins slightly diverging apicad. Antennal scape long, slightly shorter than head length. With mesosoma in dorsal view pronotum narrower than head, broader than mesonotum and propodeum; mesoscutum as long as broad, longer than half length of pronotum; mesoscutellum indistinct; scutoscutellar sulcus rather ‘broad’, comparable to metanotum, ‘widened’ medially; metanotum a ‘narrow’ impressed belt, ‘widened’ laterally; dorsum of propodeum smoothly continuous to posterior declivity, defined from the latter by different sculpturation. With mesonotum in profile view, metapleuron not clearly divided into upper and lower sections, demarcated from mesopleuron and lateral face of propodeum by distinct sulci; propodeal spiracle very small, much smaller than metathoracic spiracle, with round opening. Petiole node-like, distinctly broader than long in dorsal view, short in profile view, measuring 0.33–0.37 mm excluding very short peduncle. Gastral tergite I distinctly broader than long; prora prominent; gastric constriction moderate; cinctus inconspicuous, simple ‘narrow’ band with chain of punctures; presclerites of tergite and sternite of gastral segment II densely micropunctate. Both mid- and hindtibiae with simple spur and longer pectinate spur. Pretarsal claws of all legs pectinate. Wings absent.

Caste differences. Worker size is similar to that of queen, 4.6–5.2 mm in total body length (4.9–5.1 mm in the queen), but head is slightly narrower (0.67–0.70 mm) than in the queen (0.75–0.82 mm). In the worker caste the following features are noted: major diameter of eye: 0.20–0.23 mm; mesonotum much shorter than half length of pronotum, completely lacking mesoscutellum; petiole in dorsal view much longer than broad, in profile view triangular, much longer than in queen, measuring 0.47–0.48 mm; gaster much slenderer than in queen; gastral tergite I about as long as broad. The worker is easily separated from the queen by the long and laterally flattened petiole and much slenderer gaster.

Remarks. Queens of Leptogenys species are generally ergatoids, flightless, with the petiole shorter, broader and more node-like than in workers.

Figures

Fig. 2. Habitus (queen) in profile view.A – Hypoponera beppin Terayama, 1999 (Yakusugiland, Yaku-shima, Ôsumi Is., Kagoshima-ken, 22.viii.2006, Y. Kuboki leg., Litter No. 3); B – Anochetus shohki Terayama, 1996 (Oganzaki, Sakieda, Ishigaki-jima, Yaeyama Is., Okinawa-ken, 10.iv.2022, H. Matsumura leg., MH97, emeraged in vii.2022 from captive colony); C – Brachyponera luteipes (Mayr, 1862) (Shirahama-rindo, Iriomote-jima, Okinawa-ken, 11.xi.2018, Sk.Yamane leg., JP18-SKY-154); D – Euponera sakishimensis (Terayama, 1999) (Funaura, Iriomote-jima,Yaeyana Is., Okinawa-ken, 9.v.1979, K. Ogata leg.); E – Leptogenys confucii Forel, 1912 (Mikyo, Tokuno-shima, Amami Is., Kagoshima-ken, 6.iii.2010, Sk. Yamane leg., M10-SKY-12); F – Odontomachus cf. monticola Emery, 1892 (Miyanoura, Yaku-shima, Ôsumi Is., Kagoshima-ken, 16.ix.2008, collector unknown).

Fig. 4. Habitus (queen) in dorsal view. A – Hypoponera beppin Terayama, 1999; B – Anochetus shohki Terayama, 1996; C – Brachyponera luteipes (Mayr, 1862); D – Euponera sakishimensis (Terayama, 1999); E – Leptogenys confucii Forel, 1912; F – Odontomachus cf. monticola Emery, 1892. (Collection data same as in Fig. 2).

Fig. 6. Head (queen) in full-face view. A – Hypoponera beppin Terayama, 1999; B – Anochetus shohki Terayama, 1996; C – Brachyponera luteipes (Mayr, 1862); D – Euponera sakishimensis (Terayama, 1999); E – Leptogenys confucii Forel, 1912; F – Odontomachus cf. monticola Emery, 1892. (Collection data same as in Fig. 2).