Tetraponera kosi, 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 : 50

Tetraponera kosi sp. nov.

( Figs 32 , 45 )

Type material. Holotype worker: South Africa, KwaZulu-Natal, St. Lucia, nr Main Beach, 9 m, -28.36359 32.43065, 9 Apr 2010, nest in Vachellia kosiensis thorn, forest fringe ( Northern Coastal Forest ), P. G. Hawkes SL- MB-wp08-N ( CASENT0815472 ) ( SAMC) . Paratypes: 17 workers, 5 queens, and 3 males, same data as holotype, except collection codes SL-MB-wp08-NT-2, SL-MB-wp08-NT-3, and SL-MB-wp08-NT-4 ( CASENT0886898 to CASENT0886922) ( AFRC, CASC, MCZC, PSWC, SAMC, UCDC) .

Worker measurements (n=9). HW 0.98-1.08, HL 1.11-1.31, LHT 0.75-0.85, CI 0.82-0.88, FCI 0.10-0.13, REL 0.43-0.46, REL2 0.50-0.56, SI 0.46-0.49, SI3 0.85-0.97, FI 0.45-0.51, PLI 0.68-0.74, PWI 0.61-0.72, LHT/ HW 0.76-0.79, CSC 3-6, MSC 4-5.

Worker diagnosis. Similar to T. caffra (see above) with regard to head size, eye size, configuration of frontal carinae, and shape of anterior clypeal margin; scapes similarly short ( SI 0.46-0.49) and profemur robust ( FI 0.45- 0.51, FW/PL 0.52-0.56); mesonotum bounded posteriorly by a very weak transverse impression; metanotal plate not differentiated from dorsal face of propodeum; petiole relatively short and narrow ( PLI 0.68-0.74, PWI 0.61- 0.72, FW/ PH 0.72-0.76); in profile, petiolar node with steep anterodorsal face rounding into a more gently sloping posterodorsal face; in dorsal view, petiole narrowly obovate ( DPW /HW 0.39-0.44). Standing pilosity relatively sparse ( CSC 3-6, MSC 4-5). Medium brown, the mandibles, antennae, anterior margin of head, tibiae, and tarsi light yellowish-brown; in some workers, luteous coloration extending to parts of the pronotum, postpetiole and gaster, producing a banded pattern on the latter.

Comments. Like T. caffra , the worker of this species has rather short scapes and a robust profemur such that FW/SL 0.68-0.77 (0.69-0.76 in T. caffra ), as opposed to FW/SL 0.53-0.66 in other orange-brown and medium brown species in the T. natalensis group. Workers of T. kosi are distinguished from those of T. caffra by their predominantly darker (medium brown) coloration and a slightly less robust petiole (DPW/HW 0.39-0.44, FW/ PH 0.72-0.76, as opposed to DPW/HW 0.45-0.49, FW/ PH 0.64-0.71 in T. caffra ). Although samples sizes are small, similar differences seem to apply to the queens: those of T. kosi are predominantly medium to dark brown in color, with a more slender petiole (DPW/HW 0.48-0.51; n=4), while the queens of T. caffra are light orange-brown, with a slightly broader petiole (DPW/HW 0.53-0.56; n=2). A possible distinguishing feature of T. kosi males is longer metatibiae (LHT/HW 1.09-1.13; n=3) compared to T. caffra (LHT/HW 1.07; n=1) but this requires confirmation. At a coarse geographical scale, the known population of T. kosi is contained within the range of T. caffra ( Figs 43, 46 ), and hence the phenotypic differences between them can be interpreted as indicating that they are not conspecific. Further studies are needed, however, on the relationship between the two taxa.

Distribution and biology. T. kosi is known only from one coastal forest site in KwaZulu-Natal, South Africa, where four nest series were collected in thorns of Vachellia kosiensis , each from a different tree. The ants were found to keep scale insects in the thorns (Peter Hawkes, pers. comm., 14 January 2022), in apparent contrast to T. caffra .

Material examined. Known only from type material.

Figures

FIGURES 31–32. Tetraponera natalensis group workers, full-face (dorsal) view of head (a) and lateral profile of body (b). 31, T. setosa, holotype, Uganda (CASENT0794346); 32, T. kosi, holotype, South Africa (CASENT0815472). Images from AntWeb (www.antweb.org); photographers Matthew Prebus (31), Jill Oberski (32).

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).