Brachyponera Emery, 1900

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 : 254

Brachyponera Emery, 1900

( Figs 1A, 1D–F , 2C , 4C , 6C )

Recognition. Medium-sized ants with body length 3.8–4.6 mm; mandible with basal pit; in profile view, petiole squamiform and high with posterior portion of sternite forming spatulate lobe detached from tergite; prora apparently absent; mid- and hindtibiae with both simple and spatulate spurs.

Description. Body 3.8–4.6 mm in total length. Head 0.82–0.90 mm broad, longer than broad, with almost straight posterior margin and parallel to shallowly convex outer margins. Clypeus convex anteriad, with anterior margin medially almost straight or very shallowly emarginate. Malar space less than 0.33× major diameter of eye. Eye round, large with 13–19 ommatidia along longest axis of eye; with head in full-face view outer margin of eye slightly breaking lateral margin of head, with decumbent or apically curved hair. Mandible with basal pit, with around ten teeth of variable size along masticatory margin. Antennal scape long, surpassing posterior margin of head by more than scape diameter, with sparse short and fine hairs and appressed shorter hairs. With mesosoma in dorsal view, promesonotum narrower than head excluding eyes. Parapsidal line present on posterior half of mesoscutum; transscutal line sharply defined; scutoscutellar sulcus distinct, ‘narrowed’ medially; metanotum much shorter and narrower than mesoscutellum; in profile view mesosoma with dorsal outline evenly convex; propodeum only slightly lower than thorax; dorsum of propodeum shorter than mesoscutellum; mesopleuron extensively smooth and shiny, divided into upper and lower sections by sharply defined groove; propodeal side separated from metapleuron by weak line; propodeal spiracle small, often indistinct; its opening oval to elongate-oval; venter of thorax bearing bifurcate metasternal process. Petiole squamiform and high; posterior portion of sternite forming spatulate lobe detached from node ( Fig. 1A ). Gastral segment I with prora vestigial or apparently lacking; gastral constriction weak, but gastral segment II with pretergite generally at least partly and presternite almost always exposed in mounted specimens; pretergite and presternite superficially minutely punctostriate; cinctus not differentiated. Mid- and hindtibiae with both simple and pectinate spurs. Hindwing with jugal lobe.

Caste differences. The queen is very similar to the worker in body size, structure and coloration except for the possession of wings and associated thoracic structures and a complete set of ocelli and larger eyes in the former; in the worker the eye has 7–12 ommatidia along its longest axis (13–19 in the queen). Petiole in profile view generally relatively broader in dorsal view, thinner (shorter) in profile view than in the worker.

Remarks. All three Japanese species have winged queens only. Hairs on the eye are decumbent or apically curved; this condition may be unique in the Japanese Ponerinae . Gastral constriction is weak; exposed portion of presclerites of gastral segment II is often large in area in stretched samples and finely microsculptured. For queen and worker morphology see also YASHIRO et al. (2010).

In all the castes and sexes, the petiolar sternite has a backward-directed projection. OGATA (1987) considered it a paired structure of the subpetiolar process. Regarding the Vietnamese species EGUCHI et al. (2014) mentioned that the subpetiolar process [is] developed, posteroventrally with an acute angle or a pair of acute angles. However, the projection is actually not paired but a single flattened lobe with round posterior margin ( YAMANE 2007). The question is if this structure is part of the subpetiolar process or part of the sternite proper. This question is very difficult to answer because separation of the process from the sternite proper is in many cases ambiguous in the ponerines. If we adopt BOLTON’ s (1994) definition of subpetiolar process as an anteroventral projection on the petiole or its peduncle, then it should be located anteriorly on the sternite. According to his view, the posterior projection in Brachyponera does not belong to the subpetiolar process, because no anterior process is recognized and the projection almost reaches the posterior margin of the segment ( Fig. 1A ). The subpetiolar process is often not clearly separated from the sternite proper except for a few genera, for example Cryptopone , in which the process is lamellate and distinctive from the sternite proper ( Fig. 1B ). In Brachyponera , we cannot recognize the subpetiolar process sensu Bolton, instead the sternite is a single sclerite separated from the tergite by a distinct sulcus. We think this condition is unique to Brachyponera species.

Species examined (3/3). Brachyponera chinensis (Emery, 1895) , B. luteipes (Mayr, 1862) , B. nakasujii ( Yashiro et al., 2010) .

Figures

Fig. 1. A–C. Petiole (queen) in profile view.A – Brachyponera chinensis (Emery, 1895); B – Cryptopone sauteri (Wheeler, 1906); C – Ponera kohmoku Terayama, 1996 (S – sternite, T – tergite, Spp – subpetiolar process). D–F – metasternal process (queen) in posterior view: D – Brachyponera chinensis; E – B. luteipes (Mayr, 1862); F – B. nakasujii (Yashiro, Matuura, Guénard, Terayama & Dunn, 2010).

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).