Myrmecina subuncinata 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 subuncinata Gu & Chen sp. nov.

Fig. 53

Material examined.

Holotype. • worker, Wuzhishan , Hainan, China, 18.6698°N, 109.4525°E, 737 m, secondary forest, soil, 11. VII. 2024, Xiaoyun Liang, GXNU 242026 [ GXNU] . Paratypes. • 3 workers, with the same collection data as the holotype ; • 5 workers and 1 queens, Jianfengling , Hainan, China, 18.7113°N, 108.8766°E, 995 m, secondary forest, soil, 20. VI. 2024, Xiaoyun Liang, GXNU 240678 ; • 1 worker, Jianfenglin , Hainan, China, 18.7491°N, 108.9162°E, 672 m, secondary forest, dead wood, 22. VI. 2024, Xiaoyun Liang, GXNU 240835 ; • 2 workers, Jianfengling , Hainan, China, 18.7508°N, 108.8666°E, 811 m, secondary forest, soil, 08. VIII. 2023, Yanping Wu, GXNU 231415 [ 11 workers, GXNU; 1 worker, IZCAS] .

Diagnostic features.

(1) Anterior margin of clypeus concave, bearing a distinct transverse rectangular projection medially (non-dentiform); (2) antennal scapes smooth and shining, with sparse piliferous puncta; (3) lateroventral area of head entirely smooth and shining; (4) ventral margin of petiole convex in lateral view; (5) propodeal spines long (approximately 1.5 times basal width), abruptly tapered, and sharply upturned apically into semicircular hooks; (6) gastral tergite I with only faint striae or weak reticulation, remainder smooth and shining.

Notes.

M. subuncinata Gu & Chen , sp. nov. is most similar to M. raviwonghei but differs consistently in: (1) anterior margin of the clypeus is medially concave and bears a distinct transverse rectangular projection (non-dentiform) in M. subuncinata Gu & Chen , sp. nov. (vs. clypeal margin straight or weakly concave, with a median dentiform in M. raviwonghei . (2) antennal scapes smooth except for sparse piliferous puncta in M. subuncinata Gu & Chen , sp. nov. (vs. antennal scapes distinctly punctate in M. raviwonghei ); (3) lateroventral area of head smooth and shining in M. subuncinata Gu & Chen , sp. nov.; (vs. ventrolateral portion of head with rugae in M. raviwonghei ); (4) petiole of M. subuncinata Gu & Chen , sp. nov. with a ventral margin convex, postpetiole with rounded anterodorsal corner; sternite of postpetiole trapezoidal with straight ventral margin and dentiform postpetiolar process (vs. ventral margin of petiole is straight ventrally, ventral margin of postpetiole stronger concave with a stronger postpetiolar process in M. raviwonghei ); (5) M. subuncinata Gu & Chen , sp. nov. exhibits very faint striae or weak reticulation on the gastral tergite I, while the rest is smooth and shining in M. subuncinata Gu & Chen , sp. nov. (vs. gastral tergite I with finely punctate and gastral sternite I with reticulate in M. raviwonghei ).

Worker measurements.

(N = 3). HL 0.70–0.74, HW 0.80–0.83, CI 112–116, SL 0.53–0.54, SI 65–66, ED 0.08–0.09, MSL 0.81–0.85, PW 0.54–0.57, PL 0.24–0.26, PH 0.25–0.27, DPW 0.24–0.25, LPI 104–113, DPI 96–100, GL 1.21–1.25, TL 3.45–3.51.

Worker description.

Head. In full-face view, head trapezoidal, broader posteriorly; lateral margins convex, posterior margin medially concave with rounded posterolateral corners. Mandibles with 7 teeth: apical two teeth robust, teeth 3–6 small, low and blunt; basal tooth smaller than apical teeth. Clypeus with prominent anterolateral corners, anterior margin concave, bearing a transverse rectangular projection medially (non-dentiform). Frontal lobes strongly laterally expanded. Antennae 12 - segmented, scapes not reaching posterolateral corners. Eyes medium-sized, composed of 14–16 ommatidia. Mesosoma. In lateral view, dorsal outline weakly convex, eumetanotal spines slightly projecting above dorsal outline. Propodeal spines relatively long (1.5 times basal width), abruptly tapered apically, tips sharply upturned, forming semicircular hooks. Propodeal spiracle diameter half its distance to propodeal declivity. In dorsal view, pronotum evenly convex with prominent humeral corners; propodeal spines approximately> 2.0 times basal length, apices outwardly curved. Metasoma. In lateral view, petiole higher than long, dorsally with triangular projection posteromedially; subpetiolar process prominent, ventral margin convex. Postpetiole with rounded anterodorsal corner; sternite of postpetiole trapezoidal with straight ventral margin and dentiform postpetiolar process. Gaster ovoid. In dorsal view, petiole slightly narrower anteriorly, broader than long; postpetiole rectangular with rounded anterolateral corners; gaster anterior margin concave with distinct anterolateral corners. Sculpture. Mandibles smooth and shining except for two longitudinal basal pits; clypeus smooth. Antennal scapes smooth, except for piliferous puncta. Head densely longitudinally rugoreticulate, with punctate interrugal spaces; lateroventral areas smooth. Pronotal sides with posteriorly oblique rugae (not continuous with mesopleural and propodeal rugae). Propodeum with coarse longitudinal rugae extending to transverse inter-spinal carina; single short median carina posterior to spines. Petiole and postpetiole with short longitudinal rugae. Gastral tergite I with faint basolateral striae-reticulation, otherwise smooth. Pilosity. Body densely covered with long erect hairs; pubescence restricted to antennal club. Coloration. Mandibles, frontal lobes, antennae, and legs yellowish-brown to reddish-brown. Head, mesosoma, petiole, and postpetiole black. Gaster black with narrow midlateral area yellow-brown bands and segmental posterior margins.

Etymology.

The specific epithet “ subuncinata ” is derived from the Latin prefix “ sub - “ (meaning “somewhat” or “slightly”) combined with “ uncinatus ” (“hooked”), referring to the weakly upturned propodeal spines that distinguish this species. The name reflects the characteristic subtly curved propodeal spines, which is intermediate between the strongly hooked spines of some congeners (e. g., M. hamula ) and the weakly hooked spines of some congeners (e. g., M. eruga from Australasia).

Distribution.

Hainan.

Figures

Figure 53. Myrmecina subuncinata Gu & Chen, sp. nov. A. Propodeal spines in lateral view; B. Head in full-face view; C. Body in dorsal view; D. Body in lateral view.