Myrmecina bawai, Aswaj & Anoop & Priyadarsanan, 2021

Aswaj, Punnath, Anoop, Karunakaran & Priyadarsanan, Dharma Rajan, 2021, Description of two new species of ants of the genus Myrmecina Curtis, 1829 (Hymenoptera: Formicidae: Myrmicinae) from the Eastern Himalayas, Zootaxa 4990 (1), pp. 160-171 : 163-166

Myrmecina bawai sp. nov.

( Figures 2–3 )

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Material examined. Holotype: worker: “ India: Mizoram, Phawngpui (Blue Mountain) National Park, Lawngtlai district , (22.6907°N, 93.0492°E, 1619 m), 17.iv.2019, Pitfall trap, Coll. Punnath Aswaj and Karunakaran Anoop” ( NBAIR /HYM-FOR/9421) . Paratype: 1 worker, data same as holotype, collected in another pitfall trap ( AIMB /Hy/ Fr 25003) .

Measurements and indices. Holotype worker: HL—0.79, HW—0.80, MDL—0.46, EL—0.05, SL—0.49, TL— 3.97, WL—1.06, PNH—0.45, PNW—0.56, MW—0.48, PSL—0.22, PTH—0.29, PTL—0.28, PTW—0.25, PPH— 0.30, PPL—0.20, PPW—0.32, CI—101, MDI—58, SI—61, PI—89, PPI—160.

Paratype worker: HL—0.74, HW—0.71, MDL—0.41, EL—0.04, SL—0.48, TL—3.67, WL—0.95, PNH— 0.37, PNW—0.50, MW—0.35, PSL—0.18, PTH—0.25, PTL—0.26, PTW—0.22, PPH—0.26, PPL—0.21, PPW— 0.28, CI—96, MDI—55, SI—68, PI—85, PPI—133.

Diagnosis. Myrmecina bawai sp. nov. is unique in the following combination of characters: 1) small eyes (0.04–0.05 mm); 2) anterolateral corners of the median portion of clypeus with dentiform process; 3) absence of tooth like process on the middle anterior clypeal margin; 4) head and mesosoma with distinct rugae, the interspaces between rugae densely punctate; 5) presence of anterior pair of denticles on propodeal dorsum; 6) first gastral tergum punctulate anteriorly, coarsely reticulate medially; 7) yellow coloured body with a dark tinge.

Description. Head. In full face view, subrectangular with strongly concave occipital margin and weakly convex posterolateral margin ( Fig. 2 A ). Masticatory margin of mandible with large apical tooth followed by small preapical tooth, robust third tooth, five denticles and a blunt basal tooth ( Fig. 3 A ). Clypeus with distinctly convex posterior margin, anterior margin nearly straight, anterolateral corners of the median portion of the clypeus with dentiform process ( Figs 2 A , 3 A ). Antennae 12 segmented with three segmented club; antennal segment II pear-shaped; each segment of III–IX slightly shorter than broad; apical segment (XII) distinctly longer than segments X and XI combined. Scape almost reaching posterolateral corner of head. Eyes very small, 0.05 mm in diameter, located anteriorly at the lateral margin of head at a distance of 0.27 mm from the point of mandibular insertion ( Fig. 2 A ).

Mesosoma. In profile view, dorsal outline weakly convex, sloping backward; anterior ventrolateral corner of pronotum forming a very short tooth like process; mesonotum completely fused with pronotum; mesometapleural suture is feebly visible through the cuticle. Propodeal dorsum weakly demarcated anteriorly; metanotal groove indistinct ( Fig. 2 B ). In profile view, propodeal dorsum has a small denticle on anterior part; propodeal spines longer than broad at base, curved up apically; propodeal declivity steep and strongly concave ( Figs 2 C , 3 C ).

Metasoma. In dorsal view, petiole longer than broad, almost parallel sides; postpetiole slightly broader than petiole, broader than long, semicircular, weakly concave anterior margin and distinctly convex posterior margin ( Fig. 2 B ). In profile view, petiole almost as long as high (excluding subpetiolar process); petiolar dorsal surface weakly concave; anterior slope nearly straight; narrow subpetiolar process with relatively broad anterior tip; postpetiole slightly elevated than petiole, almost as long as high (excluding sternopostpetiolar process); sternopostpetiolar process well developed, roundly convex ventral outline, straight anterior margin ( Figs 2 C , 3 C ). Gaster slightly elongate circular with strongly concave anterior margin ( Fig. 3 D ).

Sculpture: Dorsum of head with distinct rugae, running posterolaterally, interspaces between rugae densely sculptured ( Fig. 2 A ). Mandible smooth and shiny. Mesosoma dorsally with longitudinal rugae, the rugae running continuously to lateral face ( Figs 2 C , 3 B ). Petiole and postpetiole dorsally and laterally with longitudinal rugae ( Figs 2 C , 3 C ). All the legs relatively smooth and shiny. First gastral tergum with micro-punctures (punctulate) anteriorly, coarsely reticulate medially; remaining gastral segments relatively smooth and shiny ( Fig. 3 D ).

Pilosity: Body with abundant long erect hairs. Antenna with abundant suberect and erect hairs. Mandible with numerous thin and long hairs, basal masticatory margin with few spatulate hairs. Anterolateral corner of clypeus with two pairs of relatively large erect hairs and medially with a pair of relatively small erect hairs. All legs with dense suberect to erect hairs. Gaster with abundant erect to suberect hairs.

Colour. Dorsum of head, mesosoma and gaster yellow with a dark tinge. All other body parts yellow.

Ecology. Two workers of Myrmecina bawai sp. nov. were collected from Phawngpui National Park (Blue Mountain National Park), one specimen each in two pitfall traps 200 m apart. The protected area is named for the mountain Phawngpui, often called the Blue Mountain, which is the highest mountain peak in Mizoram (maximum altitude 2157 m above sea level). The park spreads over an area of 50 km 2 and covers the Blue Mountain along with the surrounding reserve forest. The park consists of sub-tropical broadleaf and tropical evergreen forest. The annual rainfall is approximately 2500 mm and temperature ranges from 2 °C to 30 °C. The type locality is a shaded region with about 70% canopy cover.

Etymology: As Ashoka Trust for Research in Ecology and the Environment (ATREE) is celebrating its 25 th anniversary in 2021, this species is named in honour of its founder president Prof. Kamaljit S. Bawa, renowned evolutionary ecologist and conservation biologist.

Identification. Myrmecina bawai sp. nov. is close to Myrmecina taiwana Terayama, 1985 in body colour, relatively small eyes, absence of tooth like process on the middle anterior clypeal margin and presence of anterior pair of denticles on the propodeal dorsum. However it differs from M. taiwana by the following characteristics: 1) head and mesosoma with distinct rugae, the interspaces between rugae densely punctate in M. bawai (head and mesosoma with longitudinal rugose sculpture in M. taiwana ); 2) a dentiform process is present on anterolateral corners of the middle portion of the clypeus in M. bawai (dentiform process on anterolateral corner of the middle portion of the clypeus absent in M. taiwana ); 3) first gastral tergum punctulate anteriorly, coarsely reticulate medially in M. bawai (gaster smooth in M. taiwana ); 4) large size, HW 0.80, TL 3.73 in M. bawai (small size HW 0.59—0.61, TL 2.62—2.73 in M. taiwana ).

Figures

FIGURE 2. Myrmecina bawai sp. nov. worker, holotype; A) Head in full face view; B) Body in dorsal view; C) Body in profile view.

FIGURE 3. Myrmecina bawai sp. nov. worker, holotype; A) Clypeus and mandibles; B) Mesosoma in dorsal view; C) Denticle on propodeal dorsum, propodeal spine, petiole and postpetiole in profile view; D) First gastral tergum in dorsal view.