Ooceraea besucheti

The type material was collected from a soil/litter sample.

Identification
Brown (1975) - C. besucheti is clearly related to the II-segmented species of the fragosus group--Ooceraea fragosa and Ooceraea coeca, but differs in being much larger, with larger, multifacetted eyes and broader, differently shaped petiolar and postpetiolar nodes; the head is also relatively broader and more tapered anteriad.

Distribution based on Regional Taxon Lists
Oriental Region: India.

Nomenclature

 * . Cerapachys besucheti Brown, 1975: 73, figs. 79-83, 86 (w.q.) INDIA (Tamil Nadu).
 * Type-material: holotype worker, paratype workers (number not stated, “a small series”), 1 paratype ergatoid queen.
 * Type-locality: holotype India: Madras State, Anaimalai Hills, below Aliyar Dam, 1150 m., 18.xi.1972, Winkler (Besuchet, Löbl & Mussard); paratypes with same data.
 * Type-depositories: MHNG (holotype); ANIC, BMNH, MCZC, MHNG (paratypes).
 * Combination in Ooceraea: Borowiec, M.L. 2016: 198.
 * Status as species: Bolton, 1995b: 142; Bharti & Akbar, 2013a: 82 (in key); Bharti & Wachkoo, 2013d: 1192 (in key); Bharti, Guénard, et al. 2016: 21; Yamada, Luong & Eguchi, 2018: 21 (in key); Zhou, Chen & Chen 2020: 142 (in key).
 * Distribution: India.

Worker
Holotype: TL 4.4, HL 0.86, HW 0.79 (CI 92), ML 0.10, scape L 0.52, greatest diameter of eye 0.05, WL 1.17, petiolar node L 0.41, W 0.46, postpetiole L 0.41, W 0.52 mm.

Paratypes (8) range downward in body size from that of holotype; where only one measurement is given for a structure, it is the smallest made: TL 4.1, HL 0.80, HW 0.71 (CI 88-92), ML 0.09-0.12, scape L 0.48, greatest diameter of eye 0.05-0.06, WL 1.05, petiolar node L 0.37, W 0.41, postpetiole L 0.40, W 0.47 mm.

Description based on all 9 workers from the type series: A robust member of the fragosus group, with 11 antennal segments and small but convex eyes with 20-30 distinct facets in the worker. Details of body form, sculpture, and pilosity are shown well in the figures, so I shall discuss only those characters that do not show well there and those that require emphasis.

Head broadest at just about its midlength, at the level of the compound eyes, tapering markedly in front of this, and only slightly behind. Posterior border of head transverse, shallowly concave in full-face view of head, at least in the middle. Anteromedian part of clypeus without a distinct median carinula or tooth. Mandibles triangular with acute apices and sharp, concave, edentate, masticatory borders; external borders straight at midlength; surfaces densely punctate, opaque, but apical third smooth and shining.

Petiole and postpetiole both broader than long, as seen from above subtrapezoidal, wider behind, with the posterolateral angles subtuberculate, especially in postpetiole. Anterior margin of petiolar node strongly convex, of postpetiole, transverse. Petiole and postpetiole reduced nearly to myrmicine proportions in relation to the enlarged first gastric segment, which dominates the gaster, even when the apical gastric segments are extended.

Head, trunk, and both nodes densely reticulate-punctate and prevailingly opaque; gaster also densely and coarsely punctate, but less deeply so, shagreened, the spaces between punctures becoming appreciable only toward the rear of the first tergum, and even then only weakly shining, at most. The short but dense erect and suberect pilosity is supplemented by a still shorter, appressed to decumbent pubescence. Legs and antennae densely and finely punctulate, opaque or nearly so.

Color even dark reddish brown; light reddish brown in 2 specimens, probably still partly callow; legs scarcely lighter in color than body.

Queen
(Ergatoid): TL 4.7, HL 0.85, HW 0.77 (CI 91), ML 0.10, scape L 0.46, greatest diameter of eye 0.12, WL 1.22, petiolar node L 0.42, W 0.46, post petiole L 0.48, W 0.56 mm. Workerlike, but larger and with relatively slightly more robust gaster; vertex with 3 distinct ocelli.

A second ergatoid is even larger: TL 5.1, HL 0.91, HW 0.86 (CI 95), ML 0.11, scape L 0.52, WL 1.36, petiolar node L 0.46, W 0.52, postpetiole L 0.52, W 0.64 mm. In this specimen, the anteromedian ocellus is well developed, but the paired posterior ocelli are indistinct, especially the one on the right side. Compound eyes with many facets, diameter 0.13 mm.

Type Material
Holotype (MHN-Geneva) and para types from a small series taken mixed with other species of ants in a sample of soil and litter (run through a Winkler apparatus) from below Aliyar Dam in the Anaimalai Hills, 1150 m., Madras State, India, by the team of Besuchet, Lobi, and Mussard of MHN-Geneva, 18 November 1972. Paratypes in MHN-Geneva, MCZ, BMNH-London and ANIC-Canberra.

Etymology
The species is named for Dr. Claude Besuchet, one of the collectors, a prominent specialist on pselaphid beetles and curator in charge of the famous Forel Collection of ants at the Geneva museum. In this latter capacity, Dr. Besuchet has played a key role in ant systematics through his cheerful and efficient accommodation of myrmecologists seeking aid with respect to the collection.

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.