Cataulacus granulatus

Despite being a widespread and common species, we know remarkably little about the biology of Cataulacus granulatus. Bingham (1903:121) encountered Cataulacus granulatus wandering about 'apparently in an aimless sort of way.' on the bark and leaves of trees. Their nests were made in hollow branches. An ergonomic or reproductive stage colony was found in a shoot of Saraca dives in Cuc Phuong National Park in North Vietnam (Eguchi and Bui 2007). In Vietnam they nest in living and dead twigs of trees and workers forage on vegetation (Eguchi et al. 2011).

Identification
A member of the granulatus group. One of the best features available for the recognition of the species is the relatively massive and coarsely sculptured petiole. When one has acquired an eye for the characters of this genus the general build and appearance of the segments of the pedicel in granulatus are unmistakable and are only likely to be confused with the very closely related marginatus, which is, however, separable on the structure of the first gastral tergite. (Bolton 1974)

Distribution
C. granulatus is the most widely distributed species of the genus in the Indo-Australian and Oriental regions and also appears to be the most common and most variable of the known forms. The species ranges from Nepal to Ceylon and through Thailand and Burma to Hainan Is., Borneo, Sumatra and Java. (Bolton 1974)

Known from Borneo, China, India, Indonesia (Java, Sumatra), Malaysia, Myanmar, Nepal, Thailand, Singapore, and Sri Lanka.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Malaysia, Singapore. Oriental Region: Cambodia, India, Myanmar, Nepal, Sri Lanka, Thailand, Vietnam. Palaearctic Region: China.

Abundance
Common

Genetics
Polymorphic microsatellites have been identified for this species. (Debout et al. 2002)

Nomenclature

 *  granulatus. Formica granulata Latreille, 1802c: 275, pl. 12, fig. 75 (w.) "GRAND INDES". Emery, 1893e: 215 (q.m.); Bingham, 1903: 123 (q.); Bolton, 1974a: 65 (m.). Combination in Cataulacus: Smith, F. 1853: 226. Senior synonym of hispidus: Bolton, 1974a: 64.
 * hispidus. Cataulacus hispidus Smith, F. 1876d: 611, pl. 11, fig. 11 (w.) SINGAPORE. Subspecies of granulatus: Forel, 1911a: 24; Viehmeyer, 1916a: 140. Junior synonym of granulatus: Bolton, 1974a: 64.

Cataulacus hispidus

Holotype worker in. Labelled “Sing.”

Description
There is considerable variation in the length of the propodeal spines amongst the workers. Populations from Hainan Is. contain some individuals in which the spines are reduced to a pair of very small but acute teeth, and in some cases there are noticeable differences in spine length amongst members of the same series. Specimens from Java and the Andaman Is. have the hairs on the cephalic dorsum, and usually also the alitrunk, very small and somewhat clavate. In this condition the hairs resemble those found on the head of the female rather than the form usually associated with the worker caste. Sculpturation is variable in detail in the worker, as has been noted above. Usually it is the smaller individuals which possess the finer and looser rugoreticulum and more shining interspaces, but this does not by any means appear to be a hard and fast rule. (Bolton 1974)

Worker
Bolton (1974) - Bolton (1974) - TL 4.2 – 5.6, HL 1.06 – 1.30, HW 1.22 – 1.52, CI 105 - 120, EL 0.40 – 0.46, OI 27 - 33, IOD 0.90 – 1.20, SL 0.60 – 0.70, SI 45 - 49, PW 0.98 – 1.31, AL 1.16 – 1.50, MTL 0.60 – 0.77 (20 measured).

Occipital crest usually weakened or incomplete medially, the lateral portions of the crest rather poorly defined in most specimens but equipped with a few denticles. Sides of head behind eyes denticulate, the occipital corner itself with a triangular tooth, decidedly larger than the denticles of the occiput or sides. Sides of alitrunk denticulate throughout their length, the denticles extending onto the lateral margins of the propodeal spines. Pronotum broad, the mesonotum narrowing posteriorly to a notch or impression separating it from the propodeum. Propodeal spines varying in length, may be reduced to a pair of small, acute teeth but are always widely separated, little divergent and shorter than half the distance separating the one from the other. Petiole in dorsal view massive, larger than the postpetiole, both segments broader than long, sometimes distinctly so. Subpetiolar process simple or with the posteroventral angle acute or dentiform, but never drawn out into a long, spur-like projection. In profile the anterior, dorsal and posterior faces of the petiole node forming a more or less continuous convexity so that the node is roughly dome-like. Sides of first gastral tergite not marginate. In dorsal view the basal portion of the sides is jagged or denticulate, the basal border itself is not.

Sculpturation of dorsum of head and alitrunk a rugoreticulum with reticulate-punctate interspaces, very variable in intensity, and the rugae with a tendency to assume a longitudinal direction upon the mesonotum and propodeal dorsum. The rugoreticulum varies from rather coarse, close set and flattened meshes to a very fine, loose organization in which the meshes are narrow and sharply defined. The interspaces are either finely and densely reticulate-punctate, more or less mat or dully shining, or the puncturation is quite superficial, leaving the interspaces shiny, First gastral tergite very finely reticulate-rugose with punctate interspaces and with a tendency towards reduction of the rugae in smaller individuals.

Erect hairs are present on all dorsal surfaces and around the margins of the head, alitrunk, pedicel and gaster and are numerous on the appendages. The hairs are usually short, broad and blunt, but in some populations those of the head and dorsal alitrunk may be very short and more or less clavate.

Queen
Bolton (1974) - TL 6.4 – 7.2, HL 1.40 – 1.56, HW 1.48 – 1.60, CI 102 - 107, EL 0.46 – 0.50, OI 29 - 31, IOD 1.16 – 1.30, SL 0.70 – 0.'78, SI 44 - 49, PW 1.38 – 1.50, AL 1.96 – 2.14, MTL 0.62 – 0.82 (13 measured).

Similar to worker, with denticulation reduced on sides of head behind eyes and on the lateral portions of the occipital crest. The denticulation of the sides of the pronotum distinct but reduced or even absent on the propodeal margins. Propodeal spines a pair of short teeth. Sculpturation of head and pronotum similar to worker but the rugae of the mesoscutum and scutellum longitudinal, with a few cross-meshes. First gastral tergite usually with a distinct rugoreticulum on the basal quarter of its length which fades out posteriorly to a few weak, longitudinal rugulae. The entire surface finely and densely reticulate-punctate. Distribution of erect hairs as in worker but they are proportionately shorter in the present caste. Those upon the dorsum of the head (but not the margins) appear always to be very short and inconspicuous, and are often clavate or stud-like, even in populations in which the hairs are normal in the workers.

Male
Bolton (1974) - TL 4.8 – 5.4, HL 0.96 – 1.08, HW 1.10 – 1.24, CI 107 - 114, EL 0.36 – 0.40, OI 32 - 35, IOD 0.86 – 0.94, SL 0.56 – 0.64, SI 50 - 52, PW 0.92 – 1.04, AL 1.49 – 1.74, MTL 0.72 – 0.76 (5 measured).

Occipital crest incomplete medially, laterally with only one or two denticles. Sides of head behind eyes denticulate, the occipital corner with a triangular, short tooth. Lateral margins of pronotum and propodeum weakly denticulate, the propodeum with a pair of small teeth. Anterior arms of notauli developed and cross-ribbed, the posterior arm usually represented by a broad, shallow, longitudinal impression, more rarely by a distinct groove. Parapsidal furrows poorly defined, inconspicuous. Sculpturation of dorsum of head a fine loose rugoreticulum with reticulate-punctate interspaces. On the alitrunk the sculpturation is variable. Pronotum sculptured as head but the reticulum more dense; this may extend onto the mesoscutum, scutellum and propodeal dorsum but usually the cross-meshes tend to disappear, leaving these areas longitudinally rugose. Pedicel reticulate-rugose with punctate interspaces, often with the longitudinal rugae predominant. Gaster everywhere finely and densely reticulate-punctate with basigastric costulae usually present. Erect hairs present on all dorsal surfaces of head and body, simple and blunt, relatively long.

Type Material
Bolton (1974):

Formica granulate Holotype worker, 'GRAND-INDES' (location of type not known).

Cataulacus hispidus Holotype worker, SINGAPORE (UM, Oxford) [examined].