Anochetus daedalus

Anochetus daedalus has been collected from a nest in secondary tropical semi-evergreen forest from Sirsi, Karnataka, India, part of the Western Ghats biodiversity hotspot. It is very similar to Anochetus nietneri, but is distinctly different in shape of the petiole. The species is notable for constructing elaborate nest entrance which resembles ‘fort nests’ constructed by some Pheidole species.

Identification
Marathe & Priyadarsanan (2016) - This species is very similar to Anochetus nietneri. A. nietneri was described based on a single specimen in 1891 from erstwhile Ceylon (Sri Lanka). Since then, there has been no report of this species to date, except a mention in a species list. Smooth pronotal plate, bilobed clypeus, sculpture of the dorsal mesosoma and the arrangement of the denticles are similar in both species. However, A. daedalus is distinct from A. nietneri in shape of petiole, which, in lateral view, is rounded on the top in case of A. daedalus and is shaped like a pointed nib in case of A. nietneri. MdI of A. nietneri is much less (67.5 mm) than A. daedalus (74.28–74.41 mm). This species can be easily distinguished from all other Indian species by the presence of two pairs of denticles on the inner mandibular margin.

Distribution based on Regional Taxon Lists
Oriental Region: India.

Biology
Marathe & Priyadarsanan (2016) - We observed a labyrinthine fortification with magnificent architecture at the entrance of the nest from where the type materials were collected. We also noticed five similar nests in the Myristica swamp forest nearby. The entrance was always situated on a small, near-vertical plane with a single large entrance pointing downwards. The entrance was surrounded by elaborate channels constructed from mud. Certain seed harvesting Pheidole spp. construct such fortifications at the nest entrances but in a horizontal plane. To our knowledge this is the only species in the subfamily known to construct such an nest entrance. There are no data available on the method of construction or possible advantages of such a construction. This fortification could be helping the ants to prevent surface water run-off from entering the nest or to prevent raids by predators.

Nomenclature

 *  daedalus. Anochetus daedalus Marathe & Priyadarsanan, 2016: 1106, fig. 1b-d (w.) INDIA.

Worker
(mm): HL: 1.7–1.75; HW: 1.5–1.55; EL: 0.3–0.35; MdL: 1.2–1.35; SL: 1.7–1.95; PnW: 0.75–0.9; MsL: 2.2–2.6; PtW: 0.25–0.3; PtL: 0.6–0.65; PtH: 0.5–0.6; TL: 7.7–8.35. Indices: CI: 88.75–91.1; SI: 109.67–113.33; MdI: 74.28–74.41 (n = 3).

Colour and pilosity: Mesosoma and abdomen dark red, head and mandibles paler, legs yellow, pilosity moderate, erect and denser on legs, small scattered hairs present inside the antennal grooves.

Head: Slightly longer than broad. Mandibles narrower near the articulation than at the apex, anterior 70% of the length broader than the rest; first and third apical teeth large; second tooth very small, appears as a small projection on inner margin of first; fourth and fifth pairs of teeth, present on the inner margin of the mandibles, gradualy declining in size. Clypeus bilobed with the lobes blunt and projecting over the mandibles at the base. Frontal lobes large, striate, appear as two near vertical ridges converging posteriorly, not covering the antennal insertions completely and projecting over the clypeus in front. Ridges of the frontal lobes continue as striae extending slightly beyond the upper margin of eyes, along with 5–6 parallel striae on the inner side. Eyes large and situated on the anterior half of the head on the dorsal surface, with the inner margin delineated by a carina. Scape extending a little beyond the top of the head and slightly curved. Occiput prominent and bluntly emarginate, posterior margin of the head bears a prominent carina.

Mesosoma: Pronotum broader than the rest of the mesosoma, flat above; pro-mesonotal and meso-metanotal sutures distinct; mesonotum rounded; propodeum convex above and unarmed; ventral margin of episternum as well as propodeum marked by prominent carinae.

Petiole: The sub-petiolar process triangular in lateral view; the node roughly triangular or conical, the side towards the mesosoma slanting and the side facing the gaster steep.

Abdomen: Rounded on both sides, with a prominent carina at the articulation with the petiole.

Sculpture: Head in full face view mostly smooth, except for the striations between the eyes; pronotum reticulate on sides, pronotal-plate smooth and rounded, transverse striations present near articulation with head; propodeum with transverse striations on dorsal surface, changing into reticulations posteriad, striae thick and rounded, the last two striae more prominent and straight; katepisternum smooth. Petiole reticulate at base in lateral view, smooth above. Abdomen smooth and shining.

Type Material
Holotype, worker (in the Museum of the Zoological Survey of India, Western Ghats Regional Centre at Kozhikode, Kerala, No. ZSI/WGRS/IR/INV/3286) and five paratype workers (in ATREE-Insect Museum No. AIMB/ Hy/Fr23001-05), all collected from India, Karnataka, tropical evergreen forest in Sirsi (14.448°N and 74.691°E). 25.ii.2014. Coll. DRP&AM; two workers (in ATREE-Insect Museum (AIM-B/Hy/Fr23006-7)), collected in pitfall traps, India, Karnataka, natural shade coffee plantation in Kodagu (12.47715N, 75.70937E). 20.ii.2014. Coll. Clarisse Mancion.

Etymology
This species is named after the Greek mythological character Daedalus the master craftsman and architect of the ‘labyrinth’.