Liomyrmex gestroi

Workers of the single species of this genus are blind and have been found associated with termites. Rarely collected, little is known about their biology.

Identification
From Rigato and Bolton (2001) - Blind workers with smooth, thick and yellow integument. The legs and antennae are short, and the insect has an elongate, yet robust appearance. The worker caste has the following combination of characters: mandibles short and 4-toothed; bicarinate clypeus; eyes absent; scapus short and somewhat club shaped (similar to that of Vollenhovia); promesonotum flat in profile and without dorsal suture; propodeal spiracle large; propodeum unarmed; bulla of the metapleural gland long and digitiform; petiole and postpetiole massive, the former with a well developed subpetiolar lobe.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Krakatau Islands, Malaysia, New Guinea, Philippines. Oriental Region: India, Myanmar, Thailand, Vietnam.

Biology
Little is known about the biology of Liomyrmex gestroi, with most of our ideas about how they may live based on various clues from specimens and correspondence between a number of myrmecologists. Eguchi, Bui and Yamane (2011) - Eguchi found a mass of workers under bark of large fallen log in W. Bali.

The remainder of what follows is from Rigato and Bolton (2001):

A species of forest leaf-litter and topsoil, but few reports are available. Wheeler (1914) cited a letter of C.F. Baker from Philippines saying that Liomyrmex was: "abundant with termites - living in the same chambers with these in entire amity"; in the MCZ collection there are two specimens of Baker's series with a termite mounted on the same pin. Later, Wilson (1953) briefly defined Liomyrmex as "thief-ants".

One of us (B.B.) found this species in W Malaysia under a log and sharing a gallery with termites.

Lastly, B.B. Lowery (unpublished) found the species in a rotten log, not mentioning the presence of any termite.

Unfortunately the relationship of Liomyrmex to termites remains uninvestigated: Liomyrmex may be a specialised predator of isopterans; yet Wheeler (l.c.), based on Baker's comments, suggested that the association might be more intimate than a merely termite-ant predator one.

Nomenclature

 * caeca. Myrmica caeca Smith, F. 1860b: 108 (w.) NEW GUINEA. Combination in Liomyrmex: Mayr, 1865: 23 (footnote). [Junior primary homonym of Myrmica caeca Jerdon, 1851: 116.] Replacement name: gestroi Emery, 1887b: 461; earliest junior synonym of caeca (Bolton, 1995b: 248) and hence first available replacement name.
 *  gestroi. Laparomyrmex gestroi Emery, 1887b: 461, pl. 2, fig. 16 (q.) NEW GUINEA. Combination in Liomyrmex: Dalla Torre, 1893: 63. Junior synonym of caeca: Bolton, 1995b: 248 (type and other material compared), hence first available replacement name for Myrmica caeca Smith, F. 1860b: 108. [Junior primary homonym of Myrmica caeca Jerdon, 1851: 116.] Senior synonym of aurianus (and its junior synonym butteli), carinata, froggatti, major, reneae, tagalanus, taylori: Rigato & Bolton, 2001: 254.
 * aurianus. Liomyrmex aurianus Emery, 1889b: 504 (w.) MYANMAR. Wheeler, G.C. & Wheeler, J. 1955c: 128 (l.). Senior synonym of butteli: Forel, 1913k: 26. Junior synonym of gestroi: Rigato & Bolton, 2001: 245. See also: Wheeler, W.M. 1914c: 75.
 * carinatus. Liomyrmex carinata Stitz, 1911a: 366, figs. 13, 14 (q.) NEW GUINEA. Junior synonym of gestroi: Rigato & Bolton, 2001: 245.
 * butteli. Promyrma butteli Forel, 1912m: 764 (q.) WEST MALAYSIA. Junior synonym of aurianus: Forel, 1913k: 26.
 * tagalanus. Liomyrmex tagalanus Menozzi, 1925c: 445, fig. 5 (q.) PHILIPPINES. Junior synonym of gestroi: Rigato & Bolton, 2001: 245.
 * froggatti. Liomyrmex froggatti Donisthorpe, 1940a: 40, figs. 1-3 (q.m.) NEW GUINEA. Junior synonym of gestroi: Rigato & Bolton, 2001: 245.
 * major. Liomyrmex froggatti subsp. major Donisthorpe, 1941j: 204 (q.) PHILIPPINES. Junior synonym of gestroi: Rigato & Bolton, 2001: 245.
 * reneae. Liomyrmex reneae Donisthorpe, 1948a: 293, fig. 1 (w.) NEW GUINEA. Junior synonym of gestroi: Rigato & Bolton, 2001: 245.
 * taylori. Liomyrmex taylori Tiwari & Jonathan, 1986a: 88, fig. 1 (w.) ANDAMAN IS. Junior synonym of gestroi: Rigato & Bolton, 2001: 245.

Description
From Rigato and Bolton (2001):

WORKER: TL 2.8-3.9, HL 0.71-0.90, HW 0.65-0.85, CI 87-98, SL 0.32-0.41, SI 46-52, AL 0.81-1.08, PW 0.41-0.54, PeW 0.25-0.32, PeI 36-41 (59 measured).

QUEEN: TL 9-11 ca. (some specimens with an extended gaster), HL 1.35-1.50, HW 1.25-1.36, CI 89-94, SL 0.60-0.63, SI 46-48, AL 2.60-2.84, ScW 1.16-1.20, PeW 0.70-0.80, PeI 54-60 (5 measured).

This ant is remarkably uniform all over its range. The size varies considerably in single series and large workers tend to have a high CI and a more trapezoidal head, distinctly wider behind than in front.

Slight variation occurs in the pilosity. Rarely a true humeral seta may occur in addition to the usual prehumeral one; the pair of long clypeal hairs is sometimes directed upward rather than forward. Some workers have two pairs of setae on postpetiole instead of the usual one pair. Also, some hairs may be easily lost (by abrasion?).

The subpetiolar process shows slight variation in shape and size: appearing more keel-like in some, more digitiform in others; but there is no zoogeographical separation of the extremes. Also, in several nest series some variation in shape and size is plainly visible.

Body colour varies from light yellowish-brown to mid-brown.

Unfortunately we could not see type-material of Liomyrmex taylori Tiwari & Jonathan. The original description reports a comparison with L. reneae Donisthorpe, yet the differences cited seem quite weak. Moreover, the worker figured by the authors is very similar to most specimens examined by us. As Liomyrmex is very widespread in the Oriental and Indo-Australian regions, we are quite confident that L. taylori is another straightforward synonym of L. gestroi.