Syscia yekzoeae Yamane et Mizuno 2024, sp. nov.

Syscia yekzoeae Yamane et Mizuno, sp. nov. http://zoobank.org/ 86921D8F-D0C4-4B4B-9FA7- DD76AE4896DF Fig. 4A–D, 5A–D, 6A–D Type material. Holotype: worker, East Malaysia (Borneo), Sabah, Papar, Hutan Lipur, Kawang FR, 15.xi.2023, Sk. Yamane leg., SB23-SKY-04 (24 SKYRM10; ITBC). Paratypes: 1 queen, 2 workers & 2 males, same locality & date, Sk. Yamane / R. Mizuno leg., SB23-SKY-04 & RM772 (24SKYRM-11–15). Worker description. Diagnosis: Body dark reddish brown (with naked eyes looking almost black), large (3.6–4.1 mm in total length; 0.75–0.80 in head width), entirely covered with dense, coarse punctation. Parafrontal ridge with conspicuous process in anterior portion. Antenna with 9 flagellomeres (11 antennomeres). Propodeal declivity dorsolaterally with pair of short carinae. Petiole as broad as or slightly broader than long; postpetiole broader than long. Measurements (n=3): TL 3.6–4.1, HW 0.75–0.80, HL 0.90–0.93, SL 0.60–0.63, PrW 0.57–0.62, PtW 0.49–0.52, PtL 0.47–0.52, PtH 0.47–0.49, PptW 0.61–0.68, PptL 0.57–0.62, PptH 0.45–0.46, GIW 0.93–1.03, G1L 0.94–1.01. CI 83.3–86.0, SI 77.9– 80.0, G1I 99.0–104. Full description. Head in full-face view longer than broad, with very shallowly convex lateral margin, broadly emarginate posterior margin, and roundly angled posterolateral corner (Fig. 4C). Frontal carinae raised high, very close to each other, diverging anteriad; parafrontal ridge thick and well developed, with distinct process in anterior portion (Fig. 4C, arrow 1); anteriorlydirected small process present in front of each antennal socket (arrow 2). Clypeus short, much broader than long, with concave disc, and broadly and weakly convex anterior and posterior margins. Eye absent. Mandible in dorsal view subtriangular; its masticatory margin evenly and shallowly concave, edentate; basal triangular area distinctly lower than main part of mandible; apex not sharply pointed. Antenna with 9 flagellomeres (11 antennomeres); scape when laid back slightly surpassing mid-length of head, broadened apicad, outwardly curved in apical one third; venter of scape deeply excavated in apical two-fifths; the excavation flanked by high lateral carinae; pedicel small, as long as broad; flagellomeres 1– VI (antennomeres III – VIII) bead-like, each broader than long; apical flagellomere very large, much longer than two preceding ones combined; club indistinct. Mesosoma in dorsal view narrower but longer than head; pro-mesonotal suture faint; metanotal groove completely absent; posterodorsal margin of propodeum with pair of short carinae that look like propodeal spines. Mesosoma in profile view with shallowly convex dorsal outline; pronotum separated from mesopleuron with deep suture, with anteroventral corner angulate; mesopleuron demarcated from metapleuron with faint line; metapleuron fused with lateral face of propodeum; metapleural gland orifice with oblong opening and ventral wall, without peripheral hairs; propodeal spiracle very small, smaller than nearby punctures, located low on lateral face far from posterior margin of declivity; propodeal lobe round. Propodeum in posterior view with pair of upper lateral carinae that are rather high; faint carina present (can be obsolete) between them; declivity with blunt longitudinal median keel in its lower part. All femora longer than tibiae; forebasitarsus in profile view broader basally than apically; hind basitarsus in profile view broadened apicad. Petiole slightly broader than long, with anterior and posterior margin straight and lateral margin shallowly convex; postpetiole broader than long, broadened posteriad, with almost straight anterior and posterior margins. With waist in profile view, petiolar node (tergite) longer than high; sternite distinctly demarcated from node; subpetiolar process subtriangular with anterior slope longer than posterior slope; postpetiole higher than long with convex dorsal and ventral outlines; its anteroventral margin round; sternite clearly separated from tergite by deep suture (Fig. 4D). With gaster in dorsal view, tergite I nearly as long as broad, with broadly concave anterior margin and almost straight posterior margin; lateral margin roundly convex; presclerite distinctly constricted around border of tergite and sternite (Fig. 4C, arrow); cinctus dorsally cross-ribbed, forming chain of elongate punctures (Fig. 4D, cinc), but ventrally reduced; other gastral tergites combined shorter than tergite I. Almost entire body except for appendages densely covered with coarse punctures, with interspaces smooth and shiny.Area between frontal carinae and posterior half of clypeus smooth and shiny; anterior half of clypeus minutely sculptured and matte. Mandible strongly punctate with apical area, narrow area along masticatory margin and basal triangular corner smooth and shiny. Antennal scape with dense small punctures; pedicel with dense minute punctures and matte; flagellomeres I– VIII basally minutely punctate and mat, apically smooth and shiny; punctate area more extensive in flagellomeres VI – VIII; apical flagellomere entirely covered with superficial ill-defined punctuation and rather shiny. Coxae, femora and tibiae of all legs anteriorly with ill-defined irregular punctuation; tarsi with finer punctuation. Pretergite and presternite of gastral segment I with fine transverse striation. Entire body dorsally with suberect/ decumbent hairs of varying length. Lateral margin of head in full-face view with short decumbent hairs. Dorsal and lateral faces of mandible with erect/suberect hairs of varying length. Antennal scape covered with dense pubescence and with a few long suberect hairs; pedicel and flagellomeres I– VI with short erect/suberect hairs; apical three flagellomeres covered with much shorter erect hairs and sparsely with fewer slightly longer hairs. Metapleural gland orifice with a few peripheral hairs partly covering the orifice. All legs covered with near-appressed short hairs and longer suberect/ decumbent hairs of varying length. Subpetiolar process ventrally with several erect hairs; sternite of postpetiole ventrally with sparse suberect hairs; anteroventral margin of the sternite with dense short hairs. Gastral sternites with pilosity slightly sparser than on tergites. Body entirely dark reddish brown (with naked eyes almost black). Scape and apical flagellomere, and all legs much paler than body proper. Queen description. Measurements (n=1). HW 0.77, HL 0.92, SL 0.61, EW 0.10, EL 0.13, PrW 0.70, PtW 0.54, PtL 0.48, PtH 0.51, PptW 0.69, PptL 0.58, PptH 0.48, G1 W 1.12, G1L 1.06, FwL 0.52, HwL 0.40. CI 83.7, SI 79.2, G1I 106.0. Description. Similar to worker in size, structure and sculpture except for caste-specific characters mainly seen in head and mesosoma (Fig. 5A, B). Eye located at midlength of cranium, hemispherical, distinctly raised above surrounding cranial surface, with ca. 10 ommatidia that are ill defined; ocelli arranged in flat triangle; anterior ocellus larger than posterior ocellus. With mesosoma in dorsal view (Fig. 5A), mesoscutum as long as pronotum, longer than mesoscutellum, anteriorly roundly convex, demarcated from pronotum by distinct suture; scuto-scutellar suture straight; metanotum short (‘narrow’), poorly defined; propodeum as long as mesoscutellum, deeply emarginate posteriorly. With mesosoma in profile view (Fig. 5B), pronoto-mesopleural suture complete; mesopleuron not divided into upper and lower sections, poorly demarcated from metapleuron; metapleuron and lateral face of propodeum completely fused. Wings present, but vestigial (Fig. 5D); forewing with three longitudinal veinlike thickenings that are blackish, without closed cell. Body entirely orangish brown, with apical flagellomere of antenna and legs more yellowish. Male description. Measurements (n=2). HW 0.72–0.73 (HWe 0.84–0.90), HL 0.72–0.77, SL 0.33, PrW 0.78–0.82, PtW 0.38–0.39, PtL 0.33–0.35, PtH 0.37–0.42, PptW 0.46–0.48, PptL 0.44–0.47, PptH 0.50–0.53, G1 W 0.88 –0.93, G1L 0.84–0.86, FwL 2.70–2.80, HwL 1.14–1.17. CI 95.0–100.0, SI 45.2–45.8, G1I 105.8–108.1. Description. Head in full-face view as long as broad, but broader than long when including eyes (CIe: 116.7-116.9); posterior margin broadly convex with median emargination (Fig. 6C). Frontal carinae short, convergent posteriad; parafrontal ridge essentially absent; antennal scrobe small with its posterior margin located at level of posterior end of frontal carina. Clypeus clearly separated from frons by transverse ridge, with almost vertical posterior portion; anterior clypeal margin convex. Mandible subtriangular, with sharply pointed apex; masticatory margin serrate or provided with minute denticles; basal margin straight and entire.Antenna with 10 flagellomeres (12 antennomeres); scape shorter than eye width, distally widened; pedicel small, as long as flagellomere I; flagellomeres each longer than broad, getting longer towards apical flagellomere; apical flagellomere 2.4 times as long as broad. Eye large, distinctly breaking lateral margin of head; inner eye margins diverging posteriad; ocelli complete, arranged in flat triangle; distance between anterior and posterior ocelli less than diameter of ocellus; distance between posterior ocellus and eye 1.6 times as long as that between posterior ocelli. With head in profile view, occipital carina not reaching mandibular base, distinctly visible for 2/3 length of temple+gena, not forming broad flange. Mesosoma in dorsal view (Fig. 6A; wings removed) broadest at forewing bases (Fig. 6A, fwb); pronotum short, with anterolateral corner round; mesoscutum much broader than pronotum, anteriorly broadly convex, with V-shaped notauli (Fig. 6A, ntl) and weak parapsidal line that ends at posterior end of notauli; mesoscutellum separated from mesoscutum with ‘broad’ and deep furrow; its width nearly same as distance between starting points of parapsidal lines; metanotum short (‘narrow’ band); propodeum short, margined posteriorly with tran