Syscia indica

Syscia indica
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Dorylinae
Genus:	Syscia
Species:	S. indica
Binomial name
	Syscia indica; Aswaj, Sahanashree, Udayakantha, Aniruddha & Priyadarsanan, 2021

The holotype (and only known specimen of this species) 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.

Identification

Syscia indica is similar to Syscia chaladthanyakiji in general appearance and 11-segmented antennae. However, S. indica can be separated from S. chaladthanyakiji by the following characteristics:

weak sculpture with relatively small and closely-spaced foveolae in S. indica (stronger sculpturing with well-defined macropunctures in S. chaladthanyakiji)
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)
remaining gastral segments with feeble foveolae in S. indica (remaining gastral segments anteriorly with an unscupltured area in S. chaladthanyakiji)
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)
CI 74, SI 50 in S. indica (CI 80–84, SI 56–63 in S. chaladthanyakiji)

Syscia indica is also similar to the Sri Lankan and Chinese Syscia typhla in general appearance. However, the new species can be easily separated from S. typhla by the:

presence of 11-segmented antennae (9-segmented in S. typhla)
foveolae on cephalic dorsum smaller in diameter and closely spaced in S. indica (foveolae comparatively larger in diameter and widely spaced in S. typhla)
posterior cephalic margin nearly transverse in S. indica (posterior cephalic margin strongly concave in S. typhla)
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)

Du et al. (2024) - Workers have 11-segmented antennae. Head in full-face view subrectangular, distinctly longer than broad; lateral margins slightly convex. Mesosoma in dorsal view elongates with almost parallel lateral sides; in lateral view, dorsal outline almost straight. Petiole in dorsal view subrectangular, distinctly longer than broad; lateral margins almost parallel-sided; in lateral view (excluding sternite) trapezoidal, slightly shorter than high, dorsal outline slightly convex, bilateral edge slope slightly; subpetiolar process in lateral view subrectangular, ventral outline strongly concave; ventrolateral surface of petiole with two distinct almost parallel carinae just above subpetiolar process. Postpetiole in lateral view slightly shorter than high, sternite anteroventrally produced as blunt angle directed downward and forward.

Keys including this Species

Key to Asian Syscia

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 27.0433° to 27.0433°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: Aswaj et al., 2021

Distribution based on Regional Taxon Lists

Oriental Region: India.

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Biology

Castes

Worker

Du et al. (2024), Fig. 5. Syscia indica, holotype, worker. A. Head in full-face view. B. Petiole and postpetiole in dorsal view. C. Body in dorsal view D. Body in lateral view (images cited from Aswaj et al. 2021).


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Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

indica. Syscia indica Aswaj et al., 2021: 67, figs. 1, 3A–F (w.) INDIA (Arunachal Pradesh).

Type Material

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/HYMFOR/1721-2].

Description

Worker

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.

Etymology

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

References