Myrmecina planiclypea 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 planiclypea Gu & Chen sp. nov.

Fig. 45

Material examined.

Holotype. • worker, Guilin , Guangxi, China, 25.0810°N, 110.2908°E, 145 m, secondary forest, leaf litter, 10. VI. 2018, Zhilin Chen, GXNU 180016 [ GXNU] . Paratypes. • 4 workers and 1 queen, with the same collection data as the holotype [ 3 workers and 1 queen, GXNU; 1 worker, IZCAS] .

Diagnostic features.

(1) Head subquadrate, lateral margins nearly parallel and posterior margin arcuately concave; (2) mandibles with 7 distinct teeth, including 2 robust apical and subapical teeth, and a prominent basal denticle; (3) clypeus with a straight anterior margin, lacking a median denticle; (4) antennal scapes nearly reaching posterolateral corners; (5) eyes medium-sized, 10–12 ommatidia; (6) propodeal spines robust and acute, subequal in length to basal width, apices weakly curved outward; (7) anterolateral pronotal corners strongly convex, with prominent humeral corners; (8) mesosoma with longitudinal rugae and short oblique branches.

Notes.

M. planiclypea Gu & Chen , sp. nov. is most closely resembles M. guangxiensis but can be readily distinguished by the following combination of characters: (1) the lateroventral portion of the head in M. planiclypea Gu & Chen , sp. nov. bears longitudinal rugae that become sparser posteriorly, whereas M. guangxiensis exhibits irregular striations on the sides and reticulate occipital corners; (2) anterior clypeal margin in M. planiclypea Gu & Chen , sp. nov. is straight, without a median denticle, contrasting with clypeal margin in M. guangxiensis is concave, with a median denticle; (3) the eyes of M. planiclypea Gu & Chen , sp. nov. are medium-sized (10–12 ommatidia), significantly larger than the very small eyes (4–5 ommatidia) of M. guangxiensis ; (4) the propodeal spines of M. planiclypea Gu & Chen , sp. nov. are robust, acute, and subequal in length to their basal width, with apices weakly curved outward, while those of M. guangxiensis are triangular, broad at the base, and straight without upward curvature; (5) the dorsal mesosoma of M. planiclypea Gu & Chen , sp. nov. bears longitudinal rugae, with short oblique branches, while M. guangxiensis exhibits two straight longitudinal striations medially and irregular striations laterally; (6) the petiole and postpetiole in M. planiclypea Gu & Chen , sp. nov. have longitudinal rugae dorsally and laterally, whereas those in M. guangxiensis are shagreened or smooth and shining.

Worker measurements.

(N = 5). HL 0.64–0.69, HW 0.62–0.67, CI 93–96, SL 0.64–0.67, SI 102–105, ED 0.08–0.10, MSL 0.72–0.76, PW 0.43–0.44, PL 0.19–0.22, PH 0.16–0.18, DPW 0.15–0.16, LPI 88–92, DPI 79–83, GL 0.91–0.98, TL 2.64–2.88.

Worker description.

Head. In full-face view, head subquadrate, lateral margins nearly parallel and posterior margin arcuately concave; posterolateral corners rounded. Mandibles with 7 teeth: apical two teeth robust and acutely pointed, teeth 3–6 small but distinct; basal tooth larger than teeth 3–6, with a prominent denticle near inner margin. Clypeus with straight anterior margin, lacking a median denticle. Frontal lobes weakly laterally expanded. Antennae 12 - segmented, scapes nearly reaching posterolateral corners. Eyes medium-sized, composed of 10–12 ommatidia. Mesosoma. In lateral view, dorsal outline evenly convex, eumetanotal spines small, weakly projecting above dorsal outline. Propodeal spines robust and acute, length subequal to their basal width. Propodeal spiracle large, diameter almost equal to its distance to propodeal declivity. In dorsal view, anterior pronotum strongly convex, with prominent humeral corners; lateral margins gradually converging posteriorly to propodeal spine bases. Propodeal spines directed posteriorly, their apices weakly curved outward. Metasoma. In lateral view, petiole slightly longer than its height, with triangular denticulate projection posterodorsally; ventral margin straight. Postpetiole with nearly straight dorsal margin and distinct anterodorsal corners; anteroventral corner weakly denticulate; gaster ovoid. In dorsal view, petiole rectangular with concave anterior margin and straight lateral margins; postpetiole broader than its length with shallowly concave anterior margin; gaster with distinct anterolateral corners. Sculpture. Mandibles and clypeus smooth and shining, except for one long and one short basal pit on frontal mandibular surface. Head with longitudinal rugae, bearing short branchings (not forming reticulations), except smooth and shining medial frons between frontal carinae. Lateroventral portion of head with longitudinal rugae, becoming sparser posteriorly. Mesosoma with longitudinal rugae bearing short oblique branches (not reticulate). Petiole and postpetiole laterally with longitudinal rugae, dorsally with finer and denser rugae. Gaster smooth and shining. Pilosity and pubescence. Body with moderately dense erect hairs. Pubescence limited to antennal club. Coloration. Anterior head margin, posterior and ventral margins of mesosoma, petiole, pospetiole, and base and posterior of gaster reddish-brown; remainder of body black. Mandibles, clypeus, and antennae reddish-brown, except antennal club and legs yellowish-brown.

Etymology.

The specific epithet “ planiclypea ” is a Latin compound adjective derived from “ planus ” (flat, level) + “ clypeus ” (referring to the clypeus), meaning “ flat-clypeus ”. This name highlights the diagnostic straight and non-protruding anterior clypeal margin that distinguishes this species from congeners with medially denticulate or concave clypeal structures.

Distribution.

Guangxi.

Figures

Figure 45. Myrmecina planiclypea Gu & Chen, sp. nov. A. Clypeus and mandible in full-face view; B. Head in full-face view; C. Body in dorsal view; D. Body in lateral view.