Tetraponera insularis, Ward, 2022

Ward, Philip S., 2022, The ant genus Tetraponera (Hymenoptera: Formicidae) in the Afrotropical region: taxonomic review and key to species, Zootaxa 5102 (1), pp. 1-70 : 49-50

Tetraponera insularis sp. nov.

( Figs 26 , 41 )

Tetraponera psw112. Chomicki et al. 2015: figure S1. Placement in molecular phylogeny.

Type material. Holotype worker: Madagascar, Mahajanga, Forêt Anabohazo, 21.6 km 247° WSW Maromandia, 120 m, 14°19′S 47°55′E, 11–16 Mar. 2001, ex dead twig above ground, tropical dry forest, Fisher et al. BLF03360 ( CASENT0409790 ) ( CASC). Note: specimen label gives Adm1 as “Antsiranana” . Paratypes: Two workers, same data as holotype ( CASENT0409791 , CASENT0409792) ( CASC) .

Worker measurements (n=6). HW 1.27–1.54, HL 1.47–1.61, LHT 0.98–1.17, CI 0.86–0.96, FCI 0.14–0.18, REL 0.40–0.50, REL2 0.46–0.52, SI 0.50–0.55, SI3 0.98–1.20, FI 0.43–0.46, PLI 0.75–0.90, PWI 0.68–0.84, LHT/ HW 0.75–0.79, CSC 0–2, MSC 0–2.

Worker diagnosis. Large species, with relatively broad head (CI 0.86–0.96) and moderately large eyes ( REL 0.40–0.50); posterior margin of eye attaining, or nearly so, the level of the lateral ocelli; frontal carinae well separated, the minimum distance between them about 0.16× head width ( FCI 0.14–0.18) and more than one-quarter of scape length ( MFC /SL 0.28–0.33); scapes of moderate length (SI 0.50–55), equal to or exceeding eye length (SI3 0.98–1.20); anterior clypeal margin broadly and weakly convex, with a short median denticle, flanked by 3–4 denticles on each side, sometimes ill-defined ( Fig. 26a ); profemur moderately robust (FI 0.43–0.46); mesonotum bounded posteriorly by a well marked but simple impression, lacking longitudinal rugulae; distinct metanotal plate not present, although anterior extremity of propodeum with a very weakly differentiated arched-transverse area; dorsal face of propodeum flattened, laterally marginate, longer than declivitous face and rounding insensibly into the latter; petiole relatively short and high (see PLI and PWI values), dorsolaterally marginate, and with an anteroventral tooth; in profile, petiolar node with steep anterodorsal and posterodorsal faces, rounding insensibly into one another; postpetiole broader than long. Head and mesosoma densely punctulate-coriarious, matte. Standing pilosity very sparse, one or no pairs of setae on upper half of head and pronotum ( CSC 0–2, MSC 0–2), lacking on mesonotum, propodeum, and petiole; postpetiole and abdominal tergite 4 each with 0–2 standing hairs; standing pilosity distinct from the inconspicuous, short pubescence. Dark brownish-black, with contrasting luteous mandibles, antennae, and legs, except for brown band on metafemur; this lighter coloration also variably developed on the anterior half of the head capsule.

Comments. This species can be differentiated from other members of the T. natalensis group by the combination of large worker size (HW 1.27–1.54), very sparse standing pilosity (CSC 0–2, MSC 0–2), and distinctive coloration: dark-brown body with contrastingly pale-yellow appendages and a dark brown patch on the metafemur.

Distribution and biology. Tetraponera insularis is the only representative of the T. natalensis group found in Madagascar. It is known from just two collections (BLF03360, BLF40198), both from the Sahamalaza Peninsula on the northwest coast of the island, and taken from dead twigs in disturbed tropical dry forest.

Material examined ( CASC, PSWC, UCDC). Madagascar: Mahajanga: Forêt Anabohazo , 21.6 km 247° WSW Maromandia, 120 m (Fisher, B. L.; et al.); Parc Sahamalaza , Forêt Anabohazo, 141 m (Fisher, B. L.; et al.) .

Figures

FIGURES 25–27. Tetraponera natalensis group, workers, full-face (dorsal) view of head (a) and lateral profile of body (b), with inset in Figs 25b and 27b showing dorsal view of petiole, postpetiole and gaster. 25, T. caffra, South Africa (CASENT0220752); 26, T. insularis, Madagascar (CASENT0409790); 27, T. mocquerysi, Uganda (CASENT0794203). Images from AntWeb (www. antweb.org); photographer Matthew Prebus.

FIGURES 41–46. Distribution maps for Afrotropical Tetraponera. 41, T. andrei (circles), T. anthracina (triangles), T. insularis (square); 42, T. caffra (circles), T. redacta (triangles); 43, T. mocquerysi (circles), T. schulthessi (triangles); 44, T. natalensis (circles), T. setosa (triangle); 45, T. aethiops (circles), T. kosi (triangle); 46, T. latifrons (circles).