Tetramorium raptor Hita Garcia

Hita Garcia, Francisco & Fisher, Brian L., 2014, The ant genus Tetramorium Mayr in the Afrotropical region (Hymenoptera, Formicidae, Myrmicinae): synonymisation of Decamorium Forel under Tetramorium, and taxonomic revision of the T. decem species group, ZooKeys 411, pp. 67-103 : 81-83

Tetramorium raptor Hita Garcia sp. n. Figs 3, 4A, 5, 9

Type material.

Holotype, pinned worker, CAMEROON, Sud-Ouest, Bakundu, 4.49222N, 9.375E, collection code ANTC27989, 8.XI.1990 (A. Dejean) (BMNH: CASENT0195628). Paratypes, 14 pinned workers with same data as holotype (BMNH: CASENT0195581; CASENT0195630; CASENT0195631; CASC: CASENT0195633; CASENT0195634; LACM: LACM_ENT_323500; MCZ: CASENT0195628; ZFMK: CASENT0195632).

[Note: the GPS data of the type locality was not provided by the locality label. The data presented above is based on our own geo-referencing of the Bakundu Forest located in the province Sud-Ouest. Consequently, it should be considered an approximation and not the exact position of the type locality.]

Non-type material.

CAMEROON: Sud-Ouest, Bakundu, 4.49222N, 9.375E, 8.XI.1990 (A. Dejean); NIGERIA: Gambari, 10.VI.1969 (B. Bolton); Gambari, C.R.I.N., 17.VI.1975 (B. Taylor).

Diagnosis.

Tetramorium raptor is easily recognisable within the group on the basis of the following combination of characters: relatively smaller species (WL 0.88-0.93); very large eyes (OI 35); propodeum armed with very short triangular teeth (PSLI 10-11); petiolar node in profile around 1.1 times higher than long (LPeI 89-93); dorsum of mesosoma with longitudinally rugulose sculpture; body uniformly dark brown, appendages of lighter brown.

Worker measurements

(N=12). HL 0.64-0.68 (0.67); HW 0.53-0.56 (0.54); SL 0.37-0.41 (0.39); EL 0.19-0.20 (0.XX); PH 0.31 –– 0.34 (0.33); PW 0.40-0.43 (0.41); WL 0.88-0.93 (0.91); PSL 0.07-0.08 (0.07); PTL 0.23-0.25 (0.24); PTH 0.26-0.28 (0.27); PTW 0.19-0.21 (0.20); PPL 0.21-0.24 (0.22); PPH 0.25-0.28 (0.27); PPW 0.26-0.30 (0.28); CI 80-83 (82); SI 70-73 (72); OI 35; DMI 44-47 (45); LMI 35-37 (36); PSLI 10-11 (11); PeNI 47-51 (48); LPeI 89-93 (90); DPeI 80-85 (82); PpNI 64-70 (68); LPpI 81-88 (85); DPpI 123-130 (125); PPI 137-150 (142).

Worker description.

Head much longer than wide (CI 80-83); posterior head margin weakly concave. Anterior clypeal margin with distinct but often shallow median impression. Frontal carinae strongly developed and noticeably raised forming dorsal margin of very well-developed antennal scrobes, curving down ventrally and anteriorly halfway between posterior eye margin and posterior head margin and forming posterior and ventral scrobe margins; antennal scrobes very well developed, deep and with clearly defined margins all around, median scrobal carina absent. Antennal scapes short, far from reaching posterior head margin (SI 70-73). Eyes relatively large (OI 35). Mesosomal outline in profile relatively flat, elongate and low (LMI 35-37), moderately to strongly marginate from lateral to dorsal mesosoma; promesonotal suture absent; metanotal groove present and conspicuous, but relatively shallow. Propodeum armed with short, triangular, and usually acute teeth (PSLI 10-11), propodeal lobes short, well round ed, and usually larger than propodeal teeth. Petiolar node nodiform with moderately rounded antero- and posterodorsal margins, in profile around 1.1 times higher than long (LPeI 89-93), anterior and posterior faces approximately parallel, anterodorsal and posterodorsal margins situated at about same height and equally angled, petiolar dorsum weakly convex; node in dorsal view around 1.2 to 1.3 times longer than wide (DPeI 80-85), in dorsal view pronotum around 2.0 to 2.2 times wider than petiolar node (PeNI 47-51). Postpetiole in profile globular, approximately 1.1 to 1.2 times higher than long (LPpI 81-88); in dorsal view around 1.2 and 1.3 times wider than long (DPpI 123-130), pronotum around 1.4 to 1.6 times wider than postpetiole (PpNI 64-70). Postpetiole in profile appearing less voluminous than petiolar node, postpetiole in dorsal view around 1.4 to 1.5 times wider than petiolar node (PPI 137-150). Mandibles and clypeus unsculptured, smooth, and shining; cephalic dorsum between frontal carinae with fine irregularly longitudinally rugulose sculpture, rugulae running from posterior clypeal margin to posterior head margin, often interrupted or meandering, rarely with cross-meshes, cephalic dorsum also puncticulate to punctate throughout its length, otherwise without ground sculptured; scrobal area partly unsculptured, smooth and shiny and partly strongly reticulate-punctate; lateral head mainly reticulate-rugose with weak to moderately well developed punctate ground sculpture. Dorsum of mesosoma densely longitudinally rugulose, anteriorly without much ground sculpture, posteriorly on top of strong reticulate-punctate ground sculpture; lateral pronotum and katepisternum mostly unsculptured, smooth, and shiny, remainder of lateral mesosoma irregularly rugose and very conspicuously reticulate-punctate. Forecoxae unsculptured, smooth, and shining. Petiolar node laterally reticulate-punctate, dorsum of node mostly unsculptured, smooth, and shiny; postpetiole mostly unsculptured, smooth, and shiny with scattered punctures. First gastral tergite unsculptured, smooth, and shiny. Pilosity and pubescence greatly reduced: head with few pairs of moderately long, standing hairs, anterior pronotum with one long pair, waist segments sometimes with one long pair each, and sometimes first gastral tergite with one long pair; appressed pubescence present everywhere on body, but noticeable only on antennae, cephalic dorsum, legs, and first gastral tergite. Anterior edges of antennal scapes and dorsal (outer) surfaces of hind tibiae with appressed hairs. Body uniformly dark brown to black, appendages of lighter brown.

Etymology.

The name of the new species is Latin and means "thief, robber, or plunderer". It refers to the predaceous lifestyle of Tetramorium raptor . The species epithet is a nominative noun, and thus invariant.

Distribution and biology.

Tetramorium raptor is currently only known from the type locality Bakundu in the southeast of Cameroon and from Gambari in south-western Nigeria (Fig. 3). Based on the minimal collection label data, Tetramorium raptor lives in rainforest leaf litter.

Discussion.

Tetramorium raptor is an easily distinguishable member of the Tetramorium decem group, but was not recognised until this study. Indeed, all known material was collected in 1969 and 1990, but labelled as Tetramorium uelense on the basis of the distinctive sculpture on the mesosomal dorsum. The presence of conspicuous, longitudinally rugulose sculpture on the dorsum of the promesonotum distinguishes it from Tetramorium decem , Tetramorium ultor , or Tetramorium venator , since the latter three all lack sculpture on the promesonotal dorsum. Tetramorium uelense , however, shares the presence of sculpture on the mesosomal dorsum with Tetramorium raptor , which led to the abovementioned misidentifications. Nevertheless, careful examination of all material previously listed as Tetramorium uelense revealed the presence of two morphologically and ecologically different species. The most obvious differences are body size and colour. Tetramorium uelense is strongly bicoloured and larger (WL 0.98-1.06) than the smaller and uniformly-coloured Tetramorium raptor (WL 0.88-0.93). The latter also has shorter propodeal teeth (PSLI 10-11) than Tetramorium uelense (PSLI 16-18). Furthermore, Tetramorium raptor possesses a longitudinally rugulose promesonotal dorsum with very little ground sculpture and a mostly unsculptured and shiny lateral pronotum, whereas Tetramorium uelense has a promesonotal dorsum that is longitudinally rugose with distinct punctate ground sculpture and a lateral pronotum that is conspicuously rugose with prominent ground sculpture. In addition, both species also differ in habitat choice, as Tetramorium uelense seems to prefer savannah while Tetramorium raptor lives in rainforest.

Variation.

Based on material from the two known localities, there is no intraspecific variation in Tetramorium raptor .