Cataulacus latissimus

Nests of Cataulacus latissimus were found inside large branches (>5 cm in diameter) in the canopy of tropical rainforest trees. Foragers were active in the crown during the day. (Tanaka et al. 2010)

Identification
A member of the taprobanae group. By virtue of its large size, extremely broad head, laterally expanded pronotum, strongly marginate gaster and lack of hairs upon the dorsal surfaces of the head and body, the worker of this species is unlikely to be confused with any other (Bolton 1974).

Regional Cataulacus Key

Distribution
Known from Indonesia, East and West Malaysia and Singapore.

This taxon was described from West Malaysia.

Nomenclature

 *  latissimus. Cataulacus latissimus Emery, 1893e: 215, pl. 8, fig. 10 (w.) WEST MALAYSIA. Viehmeyer, 1922: 212 (q.); Bolton, 1974a: 78 (m.). Senior synonym of mimula: Bolton, 1974a: 77.
 * mimula. Cataulacus latissimus var. mimula Menozzi, 1923b: 210 (w.) BORNEO. Junior synonym of latissimus: Bolton, 1974a: 77.

Worker
Bolton (1974) - TL 6.0 – 8.0, HL 1.50 – 1.64, HW 2.16 – 2.40, CI 144 - 146, EL 0.48 – 0.54, OI 22 - 23, IOD 1.76-1.90, SL 0.86, SI ca 36, PW 1.86 – 2.20, AL 1.60 – 1.98, MTL ca 1.02 (2 measured).

Head massive, obviously much broader than long, the eyes relatively small. Occipital crest complete, sinuate with the median portion concave, and with a series of denticles along its length. Sides of head behind eyes denticulate and terminating in a subtriangular tooth at the occipital corners. Pronotum very broad, margined anteriorly by a small, raised ridge and laterally by a pair of large, flange-like expansions, the borders of which are denticulate. Mesonotum laterally with an apically bifurcate tubercle. Propodeum and basal half of the spines expanded laterally, the expanded portion denticulate along the edges. The apical halves of the spines smooth and tapering to an acute point. Promesonotal suture effaced, but its track marked by a very poorly defined impression in large workers. Also in larger workers the path of the metanotal groove may be picked out by a strip of more polished cuticle. First gastral tergite marginate around the entire circumference, strongest anteriorly and anterolaterally, less strong but still distinct elsewhere.

Sculpturation of head a fine and dense rugoreticulum with reticulate-punctate interspaces, the rugae tending to fade out anteriorly. Sculpturation of alitrunk and gaster similar to that of head, with the rugulae of the pronotum and first gastral tergite finer than those of the remainder of the alitrunk or pedicel.

Hairs absent from dorsal surfaces of head, alitrunk and gaster but present on the pedicel and around the margins of the aforementioned areas, and also upon the appendages.

Male
Bolton (1974) - Putative. TL 7.2, HL 1.36, HW 1.74, CI 128, EL 0.48, OI 28, IOD 1.46, SL 0.80, SI 46, PW 1.54, AL 2.21.

Occipital crest complete, shaped and armed as in the worker. Sides of head behind eyes denticulate, without a separate larger tooth at the occipital corner. Head distinctly broader than long, the eyes relatively larger than in the worker. Pronotum expanded laterally into a rounded flange on each side, the margins of which are denticulate and distinctly overhang the lateral portions of the sclerite. Anterior margin of pronotum with a low, transverse ridge which is broken medially. Anterior arms of notauli well developed and cross-ribbed, the posterior arm represented by a broad and shallow longitudinal groove. Parapsidal furrows present on the posterior half of the scutum. Propodeal spines distinct, short and broad. Gaster marginate laterally to the level of the spiracle of the first tergite, behind which it fades out. Spiracle of the first tergite borne upon a small tubercle, and the edge of the gaster between this and the base with two or three small denticles.

Head finely reticulate-rugose, more finely so on the anterior half where the cross-meshes are largely incomplete or absent and the rugae more or less longitudinal. Some broader, coarser rugae originate at the inner margin of each eye and run posteromedially to the occipital crest. Interspaces of the rugoreticulum finely and densely reticulate-punctate. Alitrunk with a rugoreticulum over the entire dorsum, finest on the pronotum, considerably more coarse on the propodeum and with reticulate-punctate interspaces. First gastral tergite with some basigastric costulae and a few weak, broken longitudinal rugae which do not extend onto the posterior half of the segment. Otherwise the gaster entirely reticulate-punctate. All dorsal surfaces of the head, body and appendages with erect, stout hairs.

Type Material
Bolton (1974):

Syntype workers, WEST MALAYSIA: Perak (Bedot & Pictet) (probably in MCSN, Genoa).

Cataulacus latissimus var. mimula Syntype workers, BORNEO: Brunei (Staudinger & Bang-Haas) (probably in IE, Bologna).

Additional References

 * Tanaka, H. O., S. Yamane, and T. Itioka. 2010. Within-tree distribution of nest sites and foraging areas of ants on canopy trees in a tropical rainforest in Borneo. Population Ecology. 52:147-157.