Myrmecina nigra

Nothing is known about the biology of .

Identification
Okido, Ogata, and Hosoishi (2020) - Similar to Myrmecina inthanonensis (see its identification section for details). Myrmecina nigra is distinguished by a slightly larger postpetiole than petiole, anterior clypeal margin with three processes, and mesosoma with wavy and diverging rugae on dorsal surface.

Distribution based on Regional Taxon Lists
Oriental Region: Vietnam.

Nomenclature

 * . Myrmecina nigra Okido, Ogata & Hosoishsi, 2020: 76, fig. 35 (w.) VIETNAM.

Worker
Holotype worker. TL 3.20, HL 0.77, HW 0.74, CI 96, SL 0.70, SI 96, PW 0.50, ML 0.82. Paratype workers. TL 3.05-3.36, HL 0.76-0.80, HW 0.74-0.75, CI 94-98, SL 0.67-0.69, SI 91-92, PW 0.49-0.51, ML 0.77-0.79 (4 measured).

Head subrectangular, as long as broad in full-face view or longer; median portion of occipital margin concave; occipital corners rounded, not projected posteriorly. Masticatory margin of mandible bent at midlength (third small tooth or sixth tooth); apical tooth strong, third tooth robust, followed by 5 small teeth and a basal tooth. Dorsal surface of clypeus concave; median portion of anterior margin projected with three processes; lateral portion simple, lacking sharp ridge in front of antennal insertions. Anterior dorsal surface of labrum with paired small denticles, close to each other. Frontal carinae virtually absent, indistinguishable from rugae on dorsum of head. Eyes small circularly and moderately convex, varying in size with maximum diameter 0.08-0.10 mm and 13-14 ommatidia; malar space twice as long as diameter of eye in profile; distance between occipital margin and posterior margin of eye four times as long as diameter of eye. Antennal scape long, extending beyond posterolateral corner of head; antennal flange weakly developed.

Dorsal outline of mesosoma convex in profile. Pronotum without denticles; anterior portion marginate but unclearly in dorsal view; anterior ventrolateral portion more or less angulate. Furrow between pronotum and mesoepisternal projection broad. Eumetanotal spine present but small, sometimes unclear. Propodeal spine triangular, extending over vertical posteriormost limit of propodeum in profile. Propodeal lobe low. Propodeal spiracle large, situated near base of propodeal spine, distance between posterior margin of spiracle and posterior margin of propodeum slightly longer than diameter of spiracle. Petiole short, as long as or slightly longer than high in profile, and longer than broad in dorsal view; dorsal crest located at midlength in profile; subpetiolar process variously developed from weakly raised median longitudinal ridge to distinct projection. Postpetiole slightly longer than petiole and expanded posteriorly in dorsal view; anterior portion not raised in profile; ventral outline not projected.

Anterior margin of gaster not concave in dorsal view.

Head with wavy rugae which are thin distinctly; ventrolateral portion sculptured irregularly. Clypeus smooth and shining. Mesosoma with wavy rugae distinctly. Forecoxa smooth and shining. Petiole and postpetiole with longitudinal rugae. First gastral segment smooth and shining. Head with relatively dense and long pilosity on dorsum. Mesosoma feebly dense and long pilosity on dorsum, hairs of pronotum as long as propodeal spine. Petiole without hairs on ventral surface. Postpetiole with 4 hairs on ventral surface. Body black to dark reddish brown, antennae and legs brown to yellowish brown.

Type Material
Holotype worker, VIETNAM: Deo O Quy Ho, 1750 m alt., Lao Cai Prov., 28. vi. 1997 (S. Nomura). Paratypes. 4 workers with same data as holotype (KUEC,, KUIC).