Tetraponera redacta, 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 : 58

Tetraponera redacta sp. nov.

( Figs 3 , 29 , 42 )

Type material. Holotype worker: Kenya, Kilifi: Gedi Natl. Monument, 5 m, 3°19′S 40°01′E, 17 Dec 1990, P. S. Ward PSW11180, ex dead twig of thorny vine, semideciduous forest ( CASENT0863363 ) ( NMKE) . Paratypes: Six workers, 1 male, same data as holotype ( CASENT0795283 , CASENT0886923 to CASENT0886927) ( CASC, PSWC, SAMC, UCDC) .

Worker measurements (n = 10). HW 0.97–1.16, HL 1.13–1.34, LHT 0.82–0.92, CI 0.80–0.91, FCI 0.08–0.11, REL 0.43–0.46, REL2 0.50–0.55, SI 0.50–0.53, SI3 0.94–1.05, FI 0.43–0.46, PLI 0.67–0.80, PWI 0.57–0.7, LHT/ HW 0.80–0.84, CSC 3–7, MSC 4–9.

Worker diagnosis. Relatively small species, with somewhat elongate head (CI 0.80–0.91) and moderately large eyes ( REL 0.43–0.46, REL2 0.50–0.55); posterior margin of eye not attaining the level of the lateral ocelli; frontal carinae relatively closely adjacent, the minimum distance between them about 0.10× head width ( FCI 0.08–0.11) and about one-fifth of scape length ( MFC /SL 0.16–0.22); scapes of moderate length (SI 0.50–0.53, SI2 0.41–0.48), subequal to eye length (SI3 0.94–1.05); anterior clypeal margin broadly and weakly convex, with a short median denticle, flanked by 2–3 smaller denticles on each side, rather ill-defined ( Fig. 29a ); profemur relatively slender (FI 0.43–0.46); mesonotum essentially indistinguishable from dorsal face of propodeum, not bounded posteriorly by a distinct transverse impression; dorsal face of propodeum flattened, laterally submarginate, longer than declivitous face and rounding insensibly into the latter; petiole relatively short and high ( PLI 0.67–0.80; PH /HL 0.43–0.50, PH /LHT 0.62–0.73) ( Fig. 3 ), dorsolaterally submarginate, and with an anteroventral tooth; in profile, dorsum of petiolar node more or less semicircular and with similar anterodorsal and posterodorsal faces ( Fig. 29b ); in dorsal view, petiole narrowly obovate to subtrapezoidal; postpetiole longer than broad. Head and mesosoma densely punctulate-coriarious, matte; vertex sometimes more weakly sculptured, sublucid. Standing pilosity sparse ( CSC 3–7, MSC 4–9, HTC+MTC 0); fine but dense pubescence covering most of body. Yellow- to orange-brown, with tip of gaster infuscated.

Comments. This species is difficult to distinguish from T. natalensis . In T. redacta workers the mesonotum is more or less fused with the dorsal face of the propodeum, and lies in the same plane as the latter, whereas in most workers of T. natalensis the mesonotum is separated from the propodeum by a distinct transverse impression and, in profile, it has a slight upward tilt anteriorly. This feature is variable in T. natalensis , however, and some workers approach the condition seen in T. redacta . T. redacta workers and queens have a relatively short and high petiole. Over its entire geographical range, T. natalensis shows sufficient variability in petiole shape to overlap that of T. redacta . When considering only T. natalensis workers from Kenya and Tanzania, adjacent to the range of T. redacta , differences are more pronounced and almost diagnostic ( Fig. 3 ). As far as known, the distributions of the two species do not overlap: T. redacta is restricted to coastal Kenya, while T. natalensis is found farther inland and farther south ( Figs 42, 44 ). One would be tempted, therefore, to interpret T. redacta as representing nothing more than an allopatric variant of T. natalensis , hardly deserving recognition as a distinct species. Phylogenomic (ultra-conserved element) data show, however, that T. redacta is more closely related to T. caffra than to T. natalensis (Ward, unpubl.). T. caffra occurs in southern Africa, and can be easily distinguished from both T. redacta and T. natalensis by its shorter scape and broader profemur (see key). T. redacta is thus genetically distinct from T. natalensis , despite a close similarity that is presumably attributable to either convergence or shared ancestral features.

Distribution and biology. T. redacta is known only from coastal Kenya, in littoral vegetation and semideciduous forest, where it has been found nesting in dead twigs of vines, a rutaceous (?) shrub, a scandent shrub, and other unidentified woody plants. In the residue vial of one collection (PSW11183) John Heraty discovered planidial larvae of a eucharitine wasp. Further study is needed of the distribution of T. natalensis and T. redacta in Kenya to determine if their ranges overlap. Currently the closest known populations are about 100 km apart.

Material examined ( BMNH, CASC, CUIC, MCZC, MNHN, NHMW, PSWC, UCDC, USNM). Kenya: Kilifi: 16 km WSW Malindi, 20 m (Ward, P. S.); 4 km NW Watamu, 5 m (Ward, P. S.); Gedi Natl. Monument , 5 m (Ward, P. S.); Gedi , near Malindi (Daly, H.) ; Kwale: Diani Beach [as “ Diana Beach ”] (Krauss, N. L. H.) ; Kwale, 450 m (Ross, E. S.; Leech, R. E.); Kwali Forest , 20 mi W Mombasa (Steele); Maji-Chumvi (Wa-Nyika) (Alluaud, C.); Shimba Hills (Hölldobler, B.); Simu Beach , Kwale (Ross, E. S.; Leech, R. E.); Lamu: Waboniland (c.u.) ; Mombasa: nr. Mombasa , Shanzu (Brown, L. F.) .

Figures

FIGURES 1–3. Bivariate plots of various metric measurements in Tetraponera workers. 1a, petiole height (PH) against head width (HW) in T. continua (n = 5) and T. gerdae (n = 10); 1b, postpetiole width (PPW) against head width (HW), for the same individuals; 2, scape length (SL) against head width (HW) in T. emeryi (n = 12) and T. clypeata (n = 10); 3, petiole height (PH) against length of metatibia (LHT) in T. natalensis from Kenya and Tanzania (n = 13) and T. redacta (coastal Kenya) (n = 10).

FIGURES 28–30. Tetraponera natalensis group, workers, full-face (dorsal) view of head (a) and lateral profile of body (b). 28, T. natalensis, Mozambique (CASENT0794194); 29, T. redacta, holotype, Kenya (CASENT0863363); 30, T. schulthessi, South Africa (CASENT0794193). Images from AntWeb (www.antweb.org); photographers Matthew Prebus (28, 30), Phil Ward (29).

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).