Tetraponera mandibularis (Emery)

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 : 41

Tetraponera mandibularis (Emery)

( Fig. 19 )

Sima mandibularis Emery 1895a: 340 . Holotype dealate queen (by monotypy), Diego-Suarez, Madagascar (C. Alluaud) (MSNG) [examined]. Imaged on AntWeb : CASENT0102030.

Sima flexuosa Santschi 1911b: 120 . Syntypes, 3 workers, “Madagasc.” ( MHNG, NHMB) [examined] . 2 syntype workers from NHMB imaged on AntWeb: CASENT0101154, CASENT0101155 . 1 syntype worker from MHNG imaged on AntWeb: CASENT0101979. Syn. nov .

Sima (Tetraponera) mandibularis Emery ; Emery 1921: 27. Combination in Sima (Tetraponera) .

Tetraponera mandibularis (Emery) ; Wheeler 1922c: 1015. Combination in Tetraponera .

Tetraponera mandibularis (Emery) ; Chomicki et al. 2015: figure S1. Placement in molecular phylogeny.

Sima (Tetraponera) flexuosa Santschi ; Emery 1921: 27. Combination in Sima (Tetraponera) .

Tetraponera flexuosa (Santschi) ; Wheeler 1922c: 1014. Combination in Tetraponera .

Worker measurements (n=8). HW 0.74–0.93, HL 0.95–1.23, LHT 0.70–0.91, CI 0.76–0.80, FCI 0.12–0.16, REL 0.28–0.31, REL2 0.37–0.40, SI 0.62–0.71, SI3 1.58–1.84, FI 0.40–0.43, PLI 0.51–0.57, PWI 0.41–0.45, LHT/HW 0.91–0.97, CSC 4–10, MSC 8–17.

Worker diagnosis. Moderate-sized species, with somewhat elongate head, and eyes of moderate size (see ocular indices); minimum distance between frontal carinae exceeding basal scape width; scape relatively long, about two-thirds of head width and about one-half head length (SI 0.62–0.71, SI2 0.49–0.55); median clypeal lobe protruding only slightly, weakly crenulate; profemur moderately robust (FI 0.40–0.43); mesosoma with a differentiated, transverse metanotal plate, about one third the length of the mesonotum, flanked anteriorly and posteriorly by relatively weak transverse grooves; dorsal face of propodeum subequal in length to declivitous face, and rounding insensibly into the latter; petiole relatively slender (see PLI and PWI values), with a well differentiated anterior peduncle and weak to absent anteroventral tooth, the node with relatively shallow and similar anterodorsal and posterodorsal faces, as seen in profile ( Fig. 19b ); postpetiole longer than broad. Integument shiny to sublucid, with weak reticulation and scattered punctures. Standing pilosity relatively common on head (CSC 4–10) and mesosoma (MSC 8–17), occasionally present as one to several hairs on dorsal face of propodeum. Dark brown, with antennae, mandibles, clypeus, and legs variably lighter.

Comments. Distinguishing features of the worker of T. mandibularis are its dark brown (not black) color, weakly protruding and crenulate clypeal margin, relatively long scapes (SI 0.62–0.71), moderate levels of standing pilosity, and relatively slender petiole (PLI 0.51–0.57). The queen is similar but the clypeal margin is furnished with a robust median tooth, flanked by two blunt lateral teeth. Phylogenetic analysis ( Chomicki et al. 2015) demonstrates that T. mandibularis is closely related to T. fictrix , differing primarily by its darker color ( T. fictrix is reddish-orange). There are a few collections of T. mandibularis workers that are lighter in color, suggesting the possibility of occasional introgression with T. fictrix .

Distribution and biology. This is a generalist inhabitant of dead twigs that occurs in both rainforest and tropical dry forest, from northern Madagascar south to about 23°S.

Figures

FIGURES 19–21. Tetraponera allaborans group, workers, full-face (dorsal) view of head (a) and lateral profile of body (b). 19, T. mandibularis, Madagascar (CASENT0012845); 20, T. morondaviensis, Madagascar (CASENT0012835); 21, T. sahlbergii, Madagascar (CASENT0012851). Images from AntWeb (www.antweb.org); photographer April Nobile.