Ooceraea magna Yamane et Mizuno, 2024

Ooceraea magna Yamane et Mizuno View in CoL , sp. nov.

http://zoobank.org/ 4942965D-BAE0-42E0-A7E5- A0ECD8E7E0F5

( Fig. 1A–E View Fig )

Type material. Holotype: worker, Malaysia, Borneo, Sabah, Crocker Range, Inobong , 23.ii.2006, Sk. Yamane leg. (24SKYRM-01; ITBC) . Paratype: 1 worker, same data as above (24SKYRM-02; SKYC) .

Worker description. Diagnosi s. Large species with total body length 3.7–3.9 mm and head width 0.78-0.82 mm. Entire body dark reddish brown and coarsely punctate or punctoreticulate. Antenna with 7 flagellomeres (9 antennomeres). Anterior margin of clypeus straight. Lateral margin of propodeal declivity with three denticles, the uppermost (can be called propodeal spine) being largest.

Measurements (n=2): TL 3.7–3.9, HW 0.78–0.82, HL 0.83–0.87, SL 0.52–0.55, PrW 0.58–0.63, PtW 0.42–0.43, PtL 0.45–0.47, PtH 0.38–0.40, PptW 0.44–0.48, PptL 0.48–0.50, PptH 0.45–0.49, G1 W 0.98 –1.03, G1L 1.28–1.33; CI 94.0–94.3, SI 66.7– 67.1, G1I 77.0.

Full description. Head in full-face view slightly longer than broad, with shallowly convex lateral margin, almost straight posterior margin and round posterolateral corner ( Fig. 1C View Fig ). Parafrontal ridge rather sharply carinate ( Fig. 1D View Fig , pfr). With head in profile view, posteroventral flange on temple moderately developed, medially broadly emarginate. Eye absent. Antenna with 7 flagellomeres (9 antennomeres); pedicel and flagellomere I very short and even difficult to separate. Mesosoma in dorsal view ( Fig. 1A View Fig ) narrower than head, without any transverse sutures demarcating segments; anterior slope of pronotum delimited from dorsum with transverse carina; metanotal groove absent. With mesosoma in profile view ( Fig. 1B View Fig ), pronoto-mesopleural suture sharply defined; mesopleuron, metapleuron and lateral face of propodeum nearly completely fused; propodeal spine short but distinct; propodeal lobe low. With propodeum in posterior view, declivity laterally with incomplete carina leaving two separate denticles; transverse carina between propodeal spines reduced. With waist in dorsal view, petiole slightly longer than broad, anteriorly shallowly convex, posteriorly and laterally straight; postpetiole slightly broader than petiole, slightly longer than broad, with anterior and posterior margins straight, and lateral margin very shallowly convex. With waist in lateral view, tergal portion of both petiole and postpetiole distinctly longer than high; petiole with roundly convex dorsal outline and almost straight anterior and posterior margins; subpetiolar process large, located at midlength of ventral margin of sternite, anteriorly with downward-directed small process, posteriorly with backward-directed process; postpetiole with roundly convex dorsal outline; its sternite clearly demarcated from node with sharp sulcus, anteriorly deeply concave, ventrally evenly convex. Gaster in dorsal view more than 2 times as broad as postpetiole, occupying most part of gastral dorsum, distinctly narrowed anteriad, with almost straight lateral margin in posterior twothirds; presclerites of gastral segment I narrow, 0.63 times as broad as postpetiole, dorsally with relatively long cinctus (as relatively ‘broad’ zone in front of posttergite) ( Fig. 1E View Fig , cinc).

Almost entire body coarsely punctate (partly punctoreticulate). Antennal scape and femora of all legs with finer punctation; antennal pedicel and flagellum and tibiae of all legs with still finer punctation. Cinctus of gastral tergite I basally (posteriorly) smooth; its anterior zone with chain of punctures; pretergite in front of cinctus with fine sculpture showing rectangular-shaped mesh pattern.

Body hairy, with erect/suberect hairs of various lengths over dorsal surface of head, mesosoma, waist and gaster; venter of postpetiole and gastral sternite with similar hairs; antennal scape, tibiae and tarsi with long erect hairs; antennal flagellum with shorter hairs along anterior margin of each flagellomere; long hairs on femora suberect to decumbent; pubescence lacking in most part of body; tibiae and tarsi of all legs covered with appressed hairs. Body entirely dark reddish brown; apical flagellomere yellowish.

Remarks. This is probably the largest species among the Sundaland congeners, measuring 3.7–3.9 mm in total body length and 0.78-0.82 mm in head width, but slightly smaller than the Vietnamese species O. uadridentate Yamada et al. 2018. These two species are similar to each other in body size and general appearance, but differ in the number of antennomeres (9 in the new species vs. 11 in O. uadridentate). Ooceraea magna sp. nov. is easily separated from the other Asian congeners by 1) large body size, 2) peculiar shape of the subpetiolar process, and 3) the postpetiole longer than broad. Yamane et al. (2021) recorded three species of Ooceraea from Lambir Hills National Park, Sarawak, but all had not been identified. The present new species agrees well with Ooceraea sp. 2 of SKY from Lambir.

Etymology. The specific epithet, magn a, is named after the large and sturdy body.