Tetraponera phragmotica

Tetraponera phragmotica is known only from the island of Nosy Be in northwestern Madagascar. The collections from 2 km ENE Andoany were taken in dead twigs of two adjacent Albizia trees (one recently felled, one standing) along a roadside next to mangroves. (Ward 2006)

Identification
A member of the Tetraponera ambigua-group.

Ward (2006) - Within the T. ambigua-group the (minor) worker of this species is easily recognized by its relatively large size (HW > 0.80, LHT > 0.70), broad head, dark shiny integument, and the presence of a metabasitarsal sulcus. The soldier subcaste is also very distinctive: the pronotum and head are much enlarged and the anterior portion of the head has an expanded and abruptly truncate clypeus. The truncate portion is semicircular in anterior view, with a raised outer rim and a coarsely pitted rugulose interior. The mandibles complete the truncation anteroventrally and have coarse setigerous pits. The portion of the clypeus posterior to the truncation has smaller scattered foveate pits, about 0.05 mm in diameter. The head of the queen is similarly phragmotic but also possesses distinct ocelli, which are essentially absent in the soldier.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Biology
Ward (2006) - The head of the soldier of T. phragmotica is hypertrophied and strongly truncate, with the mandibles and anterior portion of the clypeus transformed into a plug, well suited for blocking the nest entrance of these twig-dwelling ants. The form of the plug – including the pitted surface of the clypeus – is uncannily similar to Colobopsis. Cases of phragmosis are known in a few other ants (Holldobler & Wilson 1990) but the convergence with Colobopsis is especially striking in this Malagasy Tetraponera.

Nomenclature

 *  phragmotica. Tetraponera phragmotica Ward, 2006: 127, figs. 11  14, 16 (w.q.) MADAGASCAR.

Worker
Relatively large species (for the T. ambigua-group) with broad head and protruding eyes; masticatory margin of mandible with six teeth; anterior margin of clypeus broadly convex and edentate; frontal carinae separated by more than twice basal scape width; lateral ocelli present, but very small, median ocellus absent; profemur slender (FI 0.40 - 0.43); lateral pronotal margins weakly developed; profile of mesosoma dorsum as in Fig. 12, interrupted by prominently raised metanotal spiracles; dorsal face of propodeum rounding insensibly into declivitous face; petiole slender, with short anterior peduncle preceding an elongate node; metabasitarsal sulcus present as a weakly impressed line on the upper half of basitarsus. Integument largely smooth and shining, with a faint overlay of coriarious / puncticulate sculpture, most notably on dorsum of head and sides of mesosoma. Standing pilosity sparse (see CSC and MSC values), absent from mesonotum, propodeum and petiole; scattered appressed pubescence on most of body, moderately dense on abdominal tergite 4 (hairs separated by less than their lengths). Black to brownish-black, mandibles, scapes, tarsi, parts of tibiae, and distal extremities of femora lighter yellowish-brown.

Type Material
Holotype worker. Madagascar: Nosy Be, 2 km ENE Andoany (= Hellville), < 5 m (13º 24' S, 48º 18' E), 4.V.1989, ex dead twig of Albizia, roadside, leg. P.S. Ward, #10492, specimen code CASENT 0106134. Paratypes. Series of five workers (two soldiers) and two dealate queens, same locality and date as holotype, leg. P.S. Ward, #10492, 10493, 10494 ; 1 worker, Madagascar: Nosy Be airport (13º 19' S, 48º 19' E), 21.II.1991, leg. G.D. Alpert.