Syscia zhoui, Du & Xu & Chen, 2024

Du, Congcong, Xu, Zhenghui & Chen, Zhilin, 2024, Taxonomic account of the ant genus Syscia Roger, 1816 (Hymenoptera, Formicidae) from Asia, with descriptions of two new species from China, European Journal of Taxonomy 930, pp. 157-181 : 175-179

Syscia zhoui sp. nov.

urn:lsid:zoobank.org:act:02E6945A-8EE0-4244-85F8-6CC638006484

Fig. 10 , Table 1

Cerapachys typhus Gu et al., 2019: 147 , misidentification.

Diagnosis

Workers have 9-segmented antennae, body color reddish brown with antennae and legs yellowish brown. Head in full-face view subrectangular, longer than broad. Mesosoma in dorsal view subrectangular with almost parallel lateral sides; in lateral view, dorsal outline slightly convex. Petiole in dorsal view subquadrate, with lateral margins convex; in lateral view, petiolar node (excluding sternite) subquadrate with slightly convex dorsal outline, bilateral edge sloped slightly; subpetiolar process in lateral view subtriangle. Postpetiole in lateral view slightly higher than long, sternite anteroventrally produced as nearly orthogonal directed downward and forward.

Etymology

The new species is named in honor of Shanyi Zhou (Guangxi Normal University) for his outstanding contributions to the ant fauna of China.

Type material

Holotype (worker) CHINA • Guangxi, Chongzuo City, Zuozhou Town, PaiRu Village in the Chongzuo White-Headed Langur National Reserve ; 22.555816° N, 107.416772° E; 242.00 m a.s..l.; 13 Jun. 2016; Zhilin Chen leg.; No. GXNU160017 .

Paratypes (workers) CHINA • 1 worker; same collection data as for holotype; GXNU: GXNU160017-1 • 1 worker; same collection data as for holotype; SWFU: GXNU160017-2 • 1 worker; same collection data as for holotype; IZCAS: GXNU160017-3 .

Description

MEASUREMENTS AND INDICES. Holotype worker: BL 3.55, HL 0.65, HW 0.53, CI 82, SL 0.42, SI 79, MW 0.38, ML 0.60, PL 0.30, PH 0.30, PW 0.30, PI1 100, PI2 100, PPL 0.44, PPH 0.45, PPW 0.40, PPI1 97, PPI2 91, WI 133. Paratype workers: BL 3.75–3.98, HL 0.62–0.69, HW 0.50–0.56, CI 77–85, SL 0.42–0.43, SI 76–85, MW 0.31–0.38, ML 0.65–0.80, PL 0.30–0.33, PH 0.25–0.30, PW 0.25–0.35, PI1 100–120, PI2 83–117, PPL 0.45–0.48, PPH 0.42–0.48, PPW 0.42–0.45, PPI1 99–111, PPI2 89–93, WI 121–168 (n = 3) (individual measurements see Table 1 ).

Worker

HEAD. Antennae with 9 segments; scape short, not reaching mid-length of head when folded back ( Fig. 10A ). In full-face view, head subrectangular, longer than broad, lateral margins slightly convex and convergent posteriorly, posterior margin slightly concave, with posterolateral corner acute ( Fig. 10A ). Frontal carinae short and narrow, not reaching to middle of head, with anterior half sharply elevated and posterior half low and vestigial in profile. Clypeus short, anterior margin almost straight. Eyes and ocelli completely absent ( Fig. 10A ). Mandibles triangular; masticatory margin serrated, without distinct teeth ( Fig. 10A ).

MESOSOMA. In dorsal view, robust and subrectangular, with almost parallel lateral sides, anterior margin slightly convex, and posterior margin slightly concave ( Fig. 10B ); in lateral view, dorsal outline slightly convex; promesonotal suture and metanotal groove absent; mesopleuron demarcated from pronotum by distinct suture, but not demarcated from mesonotum and metapleuron; mesopleuron also not differentiated from metapleuron ( Fig. 10D ). Propodeal declivity straight, encircled with distinct thin rim ( Fig. 10D ).

METASOMA. In dorsal view, petiole subquadrate, with lateral margins convex ( Fig. 10C ); in lateral view, petiolar node (excluding sternite) subquadrate with slightly convex dorsal outline, bilateral edge sloped slightly ( Fig. 10D ). Subpetiolar process in lateral view subtriangle, with ventralopasterior corner acute and posterior outline strongly concave ( Fig. 10D ). Postpetiole in dorsal view clearly larger than petiole, subtrapezoid, anterior margin slightly concave and shorter than posterior margin, lateral margins apparently convex ( Fig. 10C ); in lateral view, postpetiole apparently shorter than high; dorsal outline slightly convex; postpetiolar sternite in lateral view really low, with ventral margin convex, anteroventrally produced as nearly orthogonal directed downward and forward ( Fig. 10D ). Abdominal tergite IV (second gastral tergite) in dorsal view elongate, subrectangular with lateral margins slightly convex, anterior margin strongly concave, and lateral margins obviously convex ( Fig. 10C ).

SCULPTURE. Entire body with numerous, relatively small, closely-spaced foveolae ( Fig. 10 ). Antennal scape, outer surface of mandible, and legs with fine dense micropunctures ( Fig. 10A, D ).

PILOSITY. Body entirely covered with densely long and short decumbent, sub-erect and erect hairs.

COLORATION. Body reddish brown. Antennae and legs yellowish brown ( Fig. 10 ).

Distribution

China (Guangxi).

Habitat

The nest of Syscia zhoui sp. nov. was found in the Chongzuo White-Headed Langur National Reserve, Guangxi, China. The sampled site is located in an evergreen broad-leaf forest, on the soil surface under the falling leaves.

Recognition

Syscia zhoui sp. nov. is a special species with antennae 9 segments, similar to S. typhla Roger, 1861 , distinctly distinguished from all other species in Syscia with antennae 11 segments. However, S. zhoui can be distinguished from S. typhla by the following characteristics: 1) head in lateral view trapezoidal in S. zhoui (head in lateral view oval in S. typhla ); 2) mesosoma rather robust, subrectangular with almost parallel lateral sides, and anterior margin slightly convex in dorsal view in S. zhoui (mesosoma rather elongate, long-ellipsoidal, with lateral sides and anterior margin obviously convex in dorsal view in S. typhla ); 3) both anterior margin and posterior margin of petiole straight in S. zhoui (both anterior margin and posterior margin of petiole convex in S. typhla ); 4) ventroposterior corner of subpetiolar process acute angled in S. zhoui (ventroposterior corner of subpetiolar process blunt rounded in S. typhla ); 5) postpetiole in dorsal view wider than long in S. zhoui (postpetiole in dorsal view longer than its width in S. typhla ).

Figures

Fig. 10. Syscia zhoui sp. nov., holotype, worker (GXNU160017). A. Head in full-face view. B. Petiole and postpetiole in dorsal view. C. Mesosoma in dorsal view. D. Body in lateral view (imaged by Zhilin Chen).