Syscia indica, Aswaj & Sahanashree & Udayakantha & Aniruddha & Priyadarsanan, 2021

Aswaj, Punnath, Sahanashree, Ramakrishnaiah, Udayakantha, Warnakulasuriyage Sudesh, Aniruddha, Marathe & Priyadarsanan, Dharma Rajan, 2021, Two new species of doryline ants (Hymenoptera, Formicidae) with 11 - segmented antennae from India, ZooKeys 1056, pp. 59-72 : 59

Syscia indica sp. nov.

Fig. 3A-F

Material examined.

Holotype One worker, Point mounted. Original label: " India, Arunachal Pradesh, West Kameng, Eaglenest WLS, 27.0434°N, 92.4302°E, 1600 m, Winkler extraction method, 10.IV.2013, Aniruddha Marathe leg." [NBAIR/HYM-FOR/1721-2].

Worker description.

Measurements and indices (holotype): BL 3.33; HL 0.68; HW 0.50; SL 0.25; PRW 0.35; WL 0.85; PL 0.36, PH 0.31, PW 0.29, PPL 0.41, PPH 0.47, PPW 0.43. Indices: CI 74, SI 50, PI1 116, PI2 81, PPI1 87, PPI2 105, WI 148 (all measurements in mm).

Head. In full-face view, rectangular, distinctly longer than broad; lateral margin weakly convex; posterior margin weakly concave (Fig. 3A ). Antennae 11-segmented, apical segment (XI) longer than IX-X combined; scape short, reaching mid-length of head when folded back. Antennal segment II almost as long as broad, segments III-X slightly broader than long (Fig. 3F ). Frontal carinae short and narrow, reaching less than half of head length. Eyes and ocelli completely absent (Fig. 3A ). Mandibles triangular; masticatory margin serrated, without distinct teeth (Fig. 3F ). Mesosoma. In dorsal view, elongate with almost parallel lateral sides (Fig. 3C ). In profile view, dorsal outline weakly convex; promesonotal suture and metanotal groove absent; mesopleuron demarcated from propleuron by a distinct pronotomesopleural suture; mesopleuron not clearly differentiated from metapleuron. Propodeal declivity feebly concave, encircled with a distinct thin rim (Fig. 3B ). Metasoma. In dorsal view, petiole distinctly longer than broad; almost parallel sided (Fig. 3D ). In profile view, petiole subrectangular; slightly longer than high with weakly convex dorsal outline. Subpetiolar process subrectangular; ventral outline strongly concave (Fig. 3B ). Postpetiole in dorsal view, larger than petiole; slightly longer than broad (Fig. 3D ). In profile view, postpetiole slightly shorter than high; dorsal outline weakly convex. Postpetiolar sternite in profile view low, ventral margin weakly convex; anteroventrally produced into a blunt angle (Fig. 3B ). Abdominal tergite IV (first gastral tergite) in dorsal view, elongate with anterior margin weakly concave; lateral sides weakly convex (Fig. 3E ). Base of cinctus of first gastral tergite with cross ribs (Fig. 3E ). Sculpture. Body with numerous, relatively small, closely-spaced foveolae. Ventrolateral surface of petiole with two distinct almost parallel carinae just above the subpetiolar process. Antennal scape, outer surface of mandible and legs with fine dense micropunctures. Pilosity. Body covered with erect and sub-erect hairs. Dorsum of postpetiole and first gastral tergite with sparse erect hairs mixed with dense long decumbent hairs. Antennae and legs with dense short decumbent hairs. Body coloration. Body reddish brown. Antennae and legs yellowish brown.

Recognition.

Syscia indica sp. nov. is similar to S. chaladthanyakiji in general appearance and 11-segmented antennae. However, S. indica can be separated from S. chaladthanyakiji by the following characteristics: 1) weak sculpture with relatively small and closely-spaced foveolae in S. indica (stronger sculpturing with well-defined macropunctures in S. chaladthanyakiji ); 2) abdominal segment IV (first gastral tergite) with large number of closely-spaced foveolae in S. indica (first gastral tergite with lesser number of relatively widely spaced foveolae in S. chaladthanyakiji ); 3) remaining gastral segments with feeble foveolae in S. indica (remaining gastral segments anteriorly with an unscupltured area in S. chaladthanyakiji ); 4) head in full-face view oval shaped with convex lateral sides and moderately concave posterior margin in S. indica (head in full-face view rectangular, almost parallel sides, posterior margin weakly concave in S. chaladthanyakiji ); 5) CI 74, SI 50 in S. indica (CI 80-84, SI 56-63 in S. chaladthanyakiji ). Syscia indica sp. nov. is also similar to the Sri Lankan and Chinese S. typhla in general appearance. However, the new species can be easily separated from S. typhla by the 1) presence of 11-segmented antennae (9-segmented in S. typhla ); 2) foveolae on cephalic dorsum smaller in diameter and closely spaced in S. indica (foveolae comparatively larger in diameter and widely spaced in S. typhla ); 3) posterior cephalic margin nearly transverse in S. Indica (posterior cephalic margin strongly concave in S. typhla ); 4) base of cinctus of first gastral tergite with cross ribs in S. indica (base of cinctus of first gastral tergite without cross ribs in S. typhla ).

Habitat.

The holotype was collected from the Eaglenest Wildlife Sanctuary at an elevation of 1600 m above sea level. The region has a canopy cover of about 85% and no indications of anthropogenic disturbances. The soil had a pH of 6.85 and temperature 16°C at the time of collection. The specimen was collected using a Winkler extractor from sifted leaf litter of 1 m2. We were able to capture one additional ant genus Carebara in the same trap, which consisted of 295 ml leaf litter.

Distribution.

Indomalaya: India (Arunachal Pradesh).

Etymology.

The specific epithet Syscia indica is a Latin singular feminine adjective in the nominative case and refers to the country where the species was collected.

Figures

Figure 3. Syscia indica sp. nov., holotype worker A head in full-face view B body in profile view C mesosoma in dorsal view D petiole and postpetiole in dorsal view E girdling constriction and gaster in dorsal view F antenna and Mandibles.