Tetraponera tucurua

This was likely the species of ant Joseph Banks mentions in his journal during a 1770 visit to Thirsty Sound, Queensland.

Identification
Ward (2001) - Workers of T. tucurua are readily identified by their small eyes, widely separated frontal carinae, and very broad petiole and postpetiole (PWI 0.79-0.88). The combination of small eyes and well-separated frontal carinae yields a ratio, MFC/EL, which is greater than that of all other Tetraponera species in Australia (0.47-0.52, v. 0.17-0.41 in six other species). The shiny integument, robust profemur, broad dorsal face of the propodeum (lying below the level of the promesonotum), and absence of standing pilosity on the mesonotum and propodeum are also characteristic features of this species.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Biology
Ward (2001) - Tetraponera tucurua is known from only two localities in southeast Queensland. At the type locality it occurred in a small patch of closed evergreen forest (“vine forest”) in a gully, with Eucalyptus overstorey. Here the species was found living inside live terminal branches of a sapindaceous tree, Cupaniopsis anacardioides, whose pith had been removed. The cavities so occupied contained adult workers, alates, brood and scale insects (Myzolecanium sp.). The workers would sting when molested. On a Cupaniopsis sapling I observed several dealate queens (one with a hindwing still attached) walking over new shoots. There were also dealate queens inside some of the new branches of this same sapling, each in a separate excavated cavity with an exit hole. Thus, it appears that colony-founding queens of T. tucurua chew their way into new shoots of Cupaniopsis, and mature colonies later occupy multiple branches. The species was briefly discussed in Ward (1991), using the appellation “Tetraponera sp. PSW -77”.

The second locality is Arthur Point, Thirsty Sound, Qld, from which there is a series of three workers and two males, collected from the hollow twig of a tree (27.v.l957; leg. A. Musgrave & G. P. Whitley) (AMSA, MCZC). No additional biological information is available on the specimen labels, but Whitley (1970: 40) discusses a collection of three ant species-identified as belonging to the genera Tetraponera and Colobopsis from the same location and date, taken from live, hollow twigs of Cupaniopsis anacardioides. There is also a herbarium specimen of Cupaniopsis anacardioides in the Royal Botanic Gardens, Sydney from Thirsty Sound, Qld (28 May 1957; leg. A. Musgrave & G. P. Whitley) with the annotation “stems hollowed out by small black ants which inhabit the galleries so formed”.

Musgrave and Whitley were on a “pilgrimage” to Thirsty Sound to commemorate Joseph Banks' visit to the same region in May 1770 (Whitley 1970). They were specifically looking for an ant-tree that Banks had encountered there and had described in his journal of 29 May 1770 as follows: “In another species of tree Xanthoxiloides mite, a small sort of black ants had bord all the twigs and livd in quantities in the hollow part where the pith should be, the tree nevertheless flourishing, bearing leaves and flowers upon those very branches as freely and well as upon others that were sound” (Beaglehole 1963: 71). Banks also records that “we of course gatherd the branches and were surprizd to find our hands instantly coverd with legions of these small animals who stung most intolerably” (Beaglehole 1963: 119). The identity of the plant is unclear-a later annotation in the Banks journal by the botanist Robert Brown gives the name as Acronychia laevis-but there is at least strong circumstantial evidence to suggest that Banks had an encounter with a Cupaniopsis tree inhabited by Tetraponera tucurua.

Cupaniopsis anacardioides is widespread in coastal wet forest in eastern and northern Australia, with a few records from New Guinea (Reynolds 1985; Adema 1991). It appears that most populations are not associated with T. tucurua. Examining herbarium specimens in the Royal Botanic Gardens (Sydney) and the Australian National Herbarium (Canberra), I found that most plant specimens did not show evidence of ant occupancy, but one collection from Dorrigo, New South Wales (Nov. 1913; R. Baker) had a suggestive exit hole in a terminal twig. It would be interesting to survey populations of C. anacardioides for their ant associates and to investigate the degree to which the ant/plant interactions are mutualistic.

Nomenclature

 *  tucurua. Tetraponera tucurua Ward, 2001: 645, figs. 90, 96, 150, 164, 176 (w.q.m.) AUSTRALIA.

Worker
HW 0.86-0.92, HL 1.02-1.15, LHT 0.64-0.71, CI 0.81-0.84, FCI 0.19-0.20, REL 0.31-0.34, REL2 0.39-0.41, SI 0.49-0.51, SI3 1.23-1.27, FI 0.50-0.53, PLI 0.78-0.82, PWI 0.79-0.88, PDI 0.99-1.07, LHT/HW 0.74-0.77, CSC 2-3, MSC 2-3.

Medium-sized species, with relatively broad head; clypeus rather short, its anteromedial portion convex, weakly crenulate, and protruding beyond level of the anterolateral clypeal margin; frontal carinae widely separated, the distance between them about 1.4x maximum scape width; eye small (REL <0.36); scape length notably longer than eye length (SI3 > 1.20); profemur short and broad (see FI values); pronotum not strongly expanded laterally (PrWM/MTW 1.13-1.22); lateral pronotal margins weakly developed; mesopropodeal impression consisting of a short, transverse pit-shaped depression, flanked by lateral ridges; propodeum about as high as wide, with a flattened and broad dorsal face that lies distinctly below the level of the promesonotum; dorsal face rounding gradually into the declivitous face; petiole with a short anterior peduncle and a broad, globular node (PLI >0.76, PWI >0.78); posterior half of petiolar sternite with prominent ventral protrusion; postpetiole about 1.4x wider than long; metabasitarsal sulcus well developed, lying in a darkened patch of cuticle occupying about half the length of the basitarsus. Integument smooth and shiny, with numerous fine punctures; punctures on dorsum of head and mesosoma mostly 0.005-0.015 mm in diameter, and separated by several diameters or more; side of mesosoma with smooth, shiny and impunctate areas, grading into regions of denser punctation on the lower mesepisternum and on the metapleuron; petiole, postpetiole and gaster finely puncticulate, sublucid; lower malar area rugulopunctate but this sculpture less extensive than in most nigra-group species. Standing pilosity relatively sparse (see CSC and MSC values), absent from mesonotum and propodeum; petiole and postpetiole each with several (about 4-6) standing hairs of variable length; rather dense pilosity (grading from erect setae to shorter suberect pubescence) on underside of head; appressed pubescence present on most of body, moderately dense on abdominal tergite IV (hairs separated by less than their lengths). Black to dark brownish-black, antennae, protibia, tarsi and (to some degree) mandibles lighter, medium-brown.

Type Material
Holotype. Worker, II km SSE Miriam Vale, Queensland, Australia, 120 m, 24°26'S 151°36'E, 5.i.l989 (P. S. Ward #9884). Paratypes. Series of workers, alate queens and males, same data as holotype.