Myrmecina spinosa

The species inhabits the soil and litter. Heterick & Kitching (2022) collected this species in a pitfall trap within a lowland dipterocarp forest in Brunei.

Identification
Okido, Ogata, and Hosoishi (2020) - A member of the Myrmecina spinosa complex. Among these species, Myrmecina tridentata and M. spinosa are distinguished by a concave anterior-margin of the first gastral tergum, bent masticatory margin of the mandible, and a propodeal spine extending backward. These two species differ by the sculpture on their head and the mesosoma; M. spinosa with straight and longitudinal rugae and M. tridentata with wavy and irregular, or transverse, rugae. The species shows wide variations in some of characters, such as the lateral lobes of the postpetiole, the position and the shape of denticles on the labrum, the body size, and number and length of the pilosity on the head and the mesosoma.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Brunei Darussalam, Indonesia, Malaysia.

Nomenclature

 * . Myrmecina spinosa Okido, Ogata & Hosoishsi, 2020: 90, fig. 42 (w.) MALAYSIA.

Worker
Holotype TL 4.21, HL 1.06, HW 1.02, CI 97, SL 0.96, SI 94, PW 0.77, ML 1.15. Paratype TL 3.87-4.10, HL 1.01-1.04, HW 0.99-1.04, CI 97-103, SL 0.83-0.94, SI 84-92, PW 0.74-0.77, ML 1.04-1.12 (3 measured). Non-type TL 2.72-3.52, HL 0.72-0.92, HW 0.67-0.85, CI 90-98, SL 0.59-0.86, SI 88-102, PW 0.53-0.62, ML 0.74-0.98 (3 measured).

Occipital margin strongly concave in full-face view; lateral margin slightly convex; occipital corners projected posteriorly. Masticatory margin of mandible bent at midlength (third small tooth or sixth tooth); apical tooth strong, third tooth robust, followed by about 5 small teeth and a stout basal tooth bearing blunt apex. Dorsal surface of clypeus concave; median portion of anterior margin weakly projected, usually with a distinct median process; lateral portion simple, lacking a sharp ridge, but slightly marginate on each side, in front of antennal insertions. Anterior dorsal surface of labrum with paired denticles usually distinct, which are well separated but varied in size and distance between denticles. Frontal carinae virtually absent indistinguishable from rugae on dorsum of head. Eyes medium-sized and convex, varying in size with maximum diameter 0.08-0.14 mm and 6-9 ommatidia. Antennal scape long, usually extending beyond posterolateral corner of head but length varied; antennal flange developed.

Dorsal outline of mesosoma slightly convex in profile. Pronotum with two or four denticles on anterior dorsolateral portion in dorsal view; anterior ventrolateral portion with denticle directing forward and downward. Eumetanotal spine long with acute apex; length usually longer than broad at base. Propodeal spine extremely long and curved abruptly upward at their shafts, much extending over vertical posteriormost limit of propodeum in profile; tips curved outward in dorsal view. Propodeal lobe raised. Propodeal spiracle situated near base of propodeal spine, distance between posterior margin of spiracle and posterior margin of propodeum slightly longer than diameter of spiracle. Petiole long; small dorsal crest located at midlength in profile; subpetiolar process present; ventral outline slightly concave. Postpetiole broader than petiole in dorsal view; lateral margin straight and marginated distinctly, sometimes lateral lobes projected; anterior portion slightly raised in profile; ventral outline projected triangularly.

Anterior margin of gaster concave in dorsal view.

Head weakly punctured with parallel rugae distinctly; ventrolateral portion with longitudinal rugae which are transversely curved at posterior portion. Mandibles usually with large yellow spots on dorsal surface. Clypeus smooth and shining. Mesosoma with parallel rugae diverging anteriorly (forming “Y”-shape); lateral portion with longitudinal or oblique rugae. Petiole and postpetiole with a few longitudinal rugae. First gastral tergum smooth and shining. Head and mesosoma with long pilosity on dorsum. Pilosity of pronotum usually longer than broad of apical second segment of antenna. Pilosity of petiole and postpetiole as long as that of mesosoma. Head, mesosoma, petiole and postpetiole black, legs yellowish, forecoxae varying from reddish brown to black, gaster reddish brown especially posterior portion lighter than anterior.

Type Material
Holotype worker, MALAYSIA: Mahua Waterfall area, ca. 1000 m alt., Crocker Range N. P., Sabah, 4. xi. 2000, MA00-HO-005 (H. Okido). Paratypes. 18 workers with same data as holotype; 13 workers with same data as holotype but MA00-HO-006; 3 workers with same data as holotype but 5. xi. 2000, MA00-HO-026.