Cerapachys indicus Brown, 1975, new species
Creators: name: Brown, W. L.
Publisher: name: Zenodo
Year: 1975
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Formicidae
Cerapachys
Cerapachys indicus

description: [56] Cerapachys indicus new species
(Figs. 58 - 65, 72)
Holotype worker, from colony no. ICA- 69: TL 4.7, HL (to anterolateral corners) 0.91, HW (without eyes) 0.77, ML 0.15, scape L 0.60, greatest diameter of eye 0.24, WL 1.35, L petiolar node (seen from above) 0.52, W petiolar node 0.49, L postpetiolar node 0.53, W postpetiolar node 0.57, L hind tibia 0.70, L hind metatarsus 0.59 mm.
Worker paratypes (7 measured), from type colony plus smaller-sized workers from Cardamon Hills, Geneva collection nos. 18 and 49: TL 4.3 - 5.5, HL 0.79 - 0.95, HW 0.63 - 0.87, ML 0.15 - 0.19, scape L 0.52 - 0.68, greatest diameter of eye 0.19 - 0.26, WL 1.17 - 1.45, L petiolar node 0.47 - 0.58, W petiolar node 0.41 - 0.55, L postpetiolar node. 0.48 - 0.59, W postpetiolar node 0.50 - 0.63 mm.
Composite description: General form and many details of a paratype (HW 0.81, WL 1.44 mm) are shown in figs. 58 to 65. Descriptive remarks will be limited to those features not seen well in the figures and the variation in the material.
Head varying greatly in face (dorsal) view with only slight changes in position of the same specimen. Posterior outline of vertex in full-face view more or less convex, often with a shallow dip in the middle, but the posterior outline of the head as a whole is completed in full-face view at a lower (more ventral) level by its cervical border and posterolateral corners, and appears sharply truncate or weakly to distinctly concave when the focus is lowered slightly from the dorsal surface of the vertex. The posterolateral corners are rectangular to weakly acute in full-face view, and appear much more acute as the head is tilted forward (fig. 59). The median point or carina and the low, rounded lobe or apron of the clypeus, as well as the distinct denticulation of the mandibles, are shown well in fig. 62.
Petiolar node longer than broad, even if only slightly, in all workers seen up to petiolar node L 0.59 mm, which is the dividing line between worker and ergatoid in the Thirunelly series (type colony); nodes larger than this are ergatoid and are broader than long. The petiolar node has a sharp, raised, transverse anterodorsal margin and a lower, indistinct posterodorsal margin; the anterodorsal margin of the postpetiole is also sharply raised (fig. 63). The anterior face of the petiolar node is densely covered with decumbent, dorsally directed pubescence, as is the anterior postpetiolar face, though less densely. Propodeal declivity shallowly concave, minutely roughened, surrounded by a sharp, semicircular margin. Subpetiolar process in side view rounded (type colony), bluntly pointed, or even bilobate (nos. 18, 49).
Two stray workers from near the type-colony site at Thirunelly have eyes smaller (diameter 0.16 - 0.18 mm) than in similarly large-sized workers of the type-colony series, but may belong to the same species. The two Cardamon Hills series are notably smaller in body size than the type-colony series. One of them (no. 18) has the foveae on the head smaller and less deep than in the other series, and the spaces between the foveae are wider, often wider than the foveae themselves on the upper vertex; but in these specimens, there is little if any reduction of the nodal and gastric sculpture. Faint lines marking the positions of promesonotal suture and metanotal groove are often present.
There is no apparent fine pubescence on the dorsal surfaces of nodes and gaster. The surface between foveae is prevailingly smooth and shining, but with a microstructure that gives clean specimens a faint bluish iridescent sheen. Color mahogany; front of head, mandibles, apical antennal segment lighter, brownish red; gaster often darker than rest of body, approaching piceous.
Ergatoid (2 paratypes from type colony): TL 5.6 - 5.7, HL 0.97 - 1.02, HW 0.87 - 0.90, ML 0.15 - 0.19, scape L 0.67 - 0.68, greatest diameter of eye 0.25 - 0.27, WL 1.60 in both specimens, L petiolar node 0.60 - 0.61, W petiolar node 0.66 - 0.69, L postpetiolar node 0.71 - 0.75, W postpetiolar node 0.83 - 0.85 mm.
Like the workers of the same colony, but a little larger, with thicker body, especially nodes and gaster. Ocelli present on vertex, but small; the anterior ocellus may be very small.
Holotype (MCZ) and 12 paratypes from type colony (no. ICA- 69) from the wooded ravine next to the temple at Thirunelly, Wynaad Taluk, about 900 m, Kerala State, India, 6 April 1969, A. B. Soans and W. L. Brown, Jr. This locality in the western Ghats still has trees shading a stream bed, and the soil was fairly moist at the time of collection. The colony was found under a stone, and stray workers were taken under other stones less than 100 m away. Other paratypes came from Winkler apparatus charged with leaf litter and forest floor debris, also from Kerala State, but farther south, in the Cardamon Hills: no. 49, 4 workers, Valara Falls, 46 km. SW of Munnar, 450 + m, 25 Nov. 1972; no. 18, 4 workers, between Pambanar and Peermade, 950 m., 9 Nov. 1972, team of Besuchet, Loebl, and Mussard from MHN-Geneva. Paratypes to be deposited in MCZ, MHN-Geneva, NM — Basel, and elsewhere.
In general habitus and its longitudinal petiolar node, C. indicus most closely resembles C. centurio [31] from central Africa, but differs from the latter in its shorter, more convex-sided head, and the deeper and more distinct, usually less crowded foveae of head and both nodes. Also, C. indicus has notably less abundant pilosity than C. centurio, and its color is a little lighter and more reddish. In the oriental region, the most similar species is C. dohertyi, which has the petiolar node broader than long, the cephalic foveae more crowded than usual in C. indicus, and the foveae-of the nodes smaller and less distinct.
description: Published as part of Brown, W. L., 1975, Contributions toward a reclassification of the Formicidae. V. Ponerinae, tribes Platythyreini, Cerapachyini, Cylindromyrmecini, Acanthostichini, and Aenictogitini., pp. 1-115 in Search: Agriculture; Cornell University Agricultural Experiment Station 15 on page 69