Camponotus horseshoetus

An unusual Camponotus species in that it possesses a metapleural gland.

Identification
Bharti and Wachkoo (2015) - This species is the only member of the genus from India, and all of southeast Asia, that possesses a metapleural gland. Its opening is positioned somewhat dorsally to where this structure is found in most formicine ants.

Distribution
Bharti and Wachkoo (2015) - This species seems to be widespread in Indian Himalaya although infrequent in collections. Previously it was known only from the Nagaland state of Northeast Himalaya (Datta and Raychaudhuri 1985). Here we report its distribution both in the Northeast Himalaya (Darjeeling, West Bengal) and Northwest Himalaya (Baijnath, Himachal Pradesh).

Distribution based on Regional Taxon Lists
Oriental Region: India.

Biology
Collected from tree branches and appears to be an arboreal forager. Datta and Raychaudhuri (1985) found workers tending groups of Aphis gossypii Glover, 1877 on Hibiscus rosasinensis Linnaeus, 1753.

Nomenclature

 *  horseshoetus. Camponotus horseshoetus Datta & Raychaudhuri, 1985: 271, fig. 1, pl. 1 (w.) INDIA. Subgenus indeterminate: Bolton, 1995b: 103.

Worker
Bharti and Wachkoo (2015) - (n=9): HL 1.14–1.30; HW 0.98–1.15; EL 0.31–0.34; SL 0.97–1.03; PW 0.67–0.78; ML 1.44–1.73; MTL 0.94–1.03; HTL 1.14–1.18; PL 0.20–0.22; GL 1.89–1.95; TL 4.68–5.16 mm. Indices: CI 86.54–88.89, SI 89.58–98.78.

Head ovoid, slightly longer than wide, narrowed anteriorly, lateral margins gently convex, posterior margin convex; clypeus in full-face view wider than long, wider anteriorly; anterolateral corners broadly rounded, mandibles slender, armed with 5-teeth, their tips overlap and the entire blades are tucked away under the clypeus in such a way that only their external margins show along the anterior clypeal margin; scape surpassing posterior cephalic margin by about one-third its length.

Mesosomal outline in profile interrupted by deep metanotal groove; promesonotum forms a regular convexity with shallow impression at promesonotal suture, metanotum lower than promesonotum and propodeal dorsum; propodeum raised, dorsal margin forms right angle with declivity; metapleural gland orifice distinct; propodeal spiracle round; in profile petiole, subrectangular, with dorsal margin sloping anteriorly; anterior margin nearly straight; posterior margin broadly concave; dorsally seen petiolar summit strongly concave; sides angulate; hind tibiae round in cross section.

Head microreticulate; remainder of the body lightly microreticulate, appearing finely striate; mesosomal, petiolar and gastral striation transverse; mesopleuron longitudinally striate; scapes microreticulate; body shiny.

Body covered with very short and very sparse appressed pubescence; head and all gastral segments with erect long setae, denser on gaster; setae absent on mesosoma and petiole; metanotal orifi ce without guard setae.

Body black; antennae and legs with reddish tinge, first gastral tergite with two yellow-brown spots anterolaterally.

Type Material
Bharti and Wachkoo (2015) - NEOTYPE: worker, INDIA: WEST BENGAL: Darjeeling, 27.0383°N 88.2620°E, 1850 m a.s.l., 20.vi.2009, hand collected (: coll. Aijaz A. Wachkoo).

Camponotus horseshoetus was originally described based on two workers, holotype and paratype from Kohima, Nagaland, India, 28.xi.1982, collected by D. R. Pramanik, and deposited in the Entomology Laboratory, Department of Zoology, Calcutta University (Datta and Raychaudhuri 1985). Unfortunately, senior author’s search of the mentioned collection failed to uncover any trace of the type specimen of this species. As the type material of this species cannot be located and is assumed to have been damaged or lost and no original material of this species exists, we therefore, in the interest of stabilizing the nomenclature, designate a neotype for Camponotus horseshoetus, using a specimen collected in Indian Himalaya, which is well within the area of its natural distribution.

References based on Global Ant Biodiversity Informatics

 * Dad J. M., S. A. Akbar, H. Bharti, and A. A. Wachkoo. 2019. Community structure and ant species diversity across select sites ofWestern Ghats, India. Acta Ecologica Sinica 39: 219–228.