Myrmecina shixui Gu & Chen, 2025

Gu, Zhuojian, Zhang, Chen, Du, Congcong & Chen, Zhilin, 2025, Synopsis of the ant genus Myrmecina Curtis, 1829 from China (Hymenoptera, Formicidae, Myrmicinae), with description of eleven new species, Deutsche Entomologische Zeitschrift 72 (2), pp. 395-448 : 395-448

Myrmecina shixui Gu & Chen sp. nov.

Fig. 50

Material examined.

Holotype. • worker, Chenggong Area , Yunnan, China, 24.8701°N, 102.7205°E, 1900 m, secondary forest, leaf litter, 17. VI. 2024, Shixu Sun, GXNU 249762 [ GXNU] . Paratype. • 3 workers, with the same collection data as the holotype [ 2 workers, GXNU; 1 worker, IZCAS] .

Diagnostic features.

(1) Densely rugose antennal scapes; (2) head subrectangular ( CI 92–98), posterior margin deeply concave; (3) clypeal margin arcuately concave, bearing a median denticle; (4) propodeal spines slender, 2 times longer than their basal width, with broadly V-shaped inter-spinal space; (5) lateroventral area of head with faint striae and smooth interspaces; dense mesosomal longitudinal rugae.

Notes.

M. shixui Gu & Chen , sp. nov. is unambiguously distinguished from all other Chinese Myrmecina species by the characters of densely rugose antennal scapes (a trait shared only with M. shanyii Gu & Chen , sp. nov. and M. hamula among regional congeners). The species is most similar to M. shanyii Gu & Chen , sp. nov. but differs markedly in multiple diagnostic traits: (1) the head of M. shixui Gu & Chen , sp. nov. is subrectangular ( CI 95–97), with projecting posterolateral corners, clypeal margin arcuately concave, bearing a median denticle, (vs. the head of M. shanyii Gu & Chen , sp. nov. is rectangular ( CI 101–104), with rounded corners, clypeal margin straight, denticle-free; (2) while both species share robust propodeal spines, M. shixui Gu & Chen , sp. nov. exhibits spines 2 times longer than their basal width (vs. length equal to basal width in M. shanyii Gu & Chen , sp. nov.); (3) though both species exhibit rugose antennal scapes, M. shixui Gu & Chen , sp. nov. shows coarse longitudinal frontal rugae (vs. oblique in M. shanyii Gu & Chen , sp. nov.); lateroventral head with faint striae and smooth interspaces in M. shixui Gu & Chen , sp. nov. (vs. punctate-rugulose in M. shanyii Gu & Chen , sp. nov.); mesosoma with dense parallel rugae (vs. irregular in M. shanyii Gu & Chen , sp. nov.).

Worker measurements.

(N = 3). HL 0.62–0.64, HW 0.59–0.62, CI 92–97, SL 0.47–0.48, SI 77–80, ED 0.07–0.08, MSL 0.76–0.80, PW 0.42–0.45, PL 0.17–0.19, PH 0.19–0.20, DPW 0.19–0.20, LPI 104–112, DPI 105–112, GL 0.91–0.98, TL 2.88–2.94.

Worker description.

Head. In full-face view, head subrectangular, slightly narrower anteriorly; posterior margin deeply concave medially. Mandibles with 8 teeth: apical two teeth largest, teeth 3–7 minutes, basal tooth larger than teeth 3–7 but distinctly smaller than apical teeth. Clypeus with prominent anterolateral projections and anterior margin arcuately concave, bearing a small median denticle. Frontal lobes strongly expanded laterally. Antennae 12 - segmented, scapes just reaching posterolateral corners. Eyes relatively large, composed of 18–20 ommatidia. Mesosoma. In lateral view, dorsal outline evenly convex, eumetanotal spines visible but not projecting above dorsal silhouette. Propodeal spines robust, basal width> length. Propodeal spiracle small, diameter about half of its distance to propodeal declivity. In dorsal view, pronotum weakly convex, with prominent humeral corners anteriorly; lateral margins gradually converging posteriorly to propodeal spine bases. Propodeal spines slender, length twice as their basal width; inter-spinal space broadly V-shaped. Metasoma. In lateral view, petiole slightly higher than long, with triangular dorsal projection; subpetiolar process bluntly angular. Postpetiole lacking a distinct node, dorsal margin nearly straight, ventral margin concave medially with a distinct anteroventral tooth. Gaster ovoid. In dorsal view, petiole and postpetiole wider than long; postpetiole without distinct anterolateral corners. Sculpture. Mandibles smooth and shining, except for two basal longitudinal grooves. Clypeus smooth and shining. Head with coarse longitudinal rugae, bearing dense fine puncta; lateroventral portion of head with faint, sparse striae, appearing mostly smooth and shining. Antennae with dense longitudinal rugae. Mesosoma with dense longitudinal rugae. Petiole and postpetiole with short longitudinal rugae; gaster smooth and shining. Pilosity and pubescence. Body with moderately dense erect hairs. Pubescence restricted to antennal club. Coloration. Body black; mandibles, antennae, and legs dark brown, antennal club slightly lighter.

Etymology.

The specific epithet “ shixui ” is a Latinized genitive noun derived from the given name “ Shixu ” of the collector Mr. Shixu Sun. The name is formed by adding the patronymic suffix * - i * to the stem “ Shixu ” and honors Mr. Sun’s contributions in collecting the type specimens of M. shixui Gu & Chen , sp. nov.

Distribution.

Yunnan.

Figures

Figure 50. Myrmecina shixui Gu & Chen, sp. nov. A. Petiole in lateral view; B. Head in full-face view; C. Body in dorsal view; D. Body in lateral view.