Strumigenys geoterra

Known from rainforest litter and soil sampling.

Identification
Bolton (2000) - A member of the Strumigenys lujae-group. Dorsum and sides of alitrunk, and disc of postpetiole, glassy smooth everywhere. Anterolateral angles of mesonotum elevated and strongly prominent. Apicoscrobal and pronotal humeral hairs absent. Eyes not visible in full-face view. Ground-pilosity on all dorsal surfaces of head and body of short broadly spatulate to spoon-shaped hairs; main pilosity is of enlarged versions of this. Appressed hairs on femora and tibiae very dense, short and broadly spatulate to scale-like. Femoral gland bullae large on all legs but partially concealed by the pilosity.

Bolton (1983) - This very distinctive species appears closest related to Strumigenys maynei, the two having broad upper scrobe margins, conspicuous cephalic ground-pilosity, lacking flagellate hairs on the head and pronotum, lacking dense punctate pronotal sculpture, and having antennal scapes of moderate length. They are easily separated as geoterra has the alitrunk absolutely smooth whilst in maynei sculpture is present. Apart from this the alitrunk is characteristically shaped in geoterra, the cephalic pilosity is evelll broader and coarser than in maynei, and the sides of the head are conspicuously more convex because of the wide upper scrobe margin in geoterra.

Distribution based on Regional Taxon Lists
Afrotropical Region: Cameroun, Gabon, Kenya, Uganda.

Nomenclature

 *  geoterra. Serrastruma geoterra Bolton, 1983: 341, fig. 36 (w.) CAMEROUN. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 120. See also: Bolton, 2000: 313.

Worker
Holotype. TL 2.6, HL 0.58, HW 0.2, CI 90, ML 0.23, MI 40, SL 0.38, SI 73, PW 0.34, AL 0.74.

Mandibles with denticles very slightly enlarging basally, the increase in size minute and gradual, without a suddenly much enlarged basal series. False anterior margin of clypeus with a row of very conspicuous broad flattened hairs which project straight forwards over the real clypeal margin and the bases of the mandibles. Upper scrobe margins expanded into a very broad conspicuous lamella which runs the length of the scrobe, is slightly elevated and is of approximately equal width throughout its length. This upper scrobal lamella is so broad posteriorly that the eyes are concealed and not visible in full-face view; the margin without a pair of projecting long hairs just behind the level of the eyes. Antennal scapes feebly curved, broadened after the basal third and narrowing again apically, their leading edges with a projecting row of short broad flattened hairs which are truncated apically. Ground-pilosity of head consisting everywhere of very thick short blunt off-white to yellowish hairs which in profile can be seen to be dorsoventrally flattened and strongly curved anteriorly. Close to the occipital margin is a single pair of similarly constructed but longer, slightly more erect hairs. Eyes small, of 5-6 ommatidia. Clypeus with very feeble superficial reticular sculpture, a narrow strip behind the clypeus and following the shape of the posterior clypeal margin depressed and smooth. Behind this the head weakly reticulate-punctate, this sculpture fading posteriorly and the area between the highest point of the vertex and the occipital margin smooth except for the pits from which the hairs arise. Broad flange of upper scrobe margin densely reticulate-granular. Pronotum not marginate laterally, the humeri without flagellate hairs. Pronotum in dorsal view almost twice wider than the mesonotum, the two separated by a shallow arched-transverse impression. Metanotal groove represented by a transverse line across the dorsum but not impressed. With the alitrunk in profile the pronotal outline separated by a shallow impression from the mesonotum, the anterior half of the latter raised and on the same level as the pronotum. Behind this the mesonotum descending almost vertically and its posterior half flat or shallowly concave to the level of the metanotal groove, behind which the propodeal dorsum is shallowly convex and sloping posteriorly. Propodeal teeth triangular, with a narrow but conspicuous infradental lamella. Dorsum and sides of alitrunk glassy smooth everywhere, the propodeal declivity with reticular vestiges on its upper half. Pilosity of dorsal alitrunk as on head, the hairs curved anteriorly or medially on the pronotum and mesonotum, posteriorly on the propodeum. Mesonotum with a pair of similarly constructed but larger hairs at the point where the surface begins its sudden descent. Spongiform appendages of pedicel segments small, the subpetiolar process reduced to a thin strip and the subpostpetiolar lobe much smaller than the exposed area of the postpetiolar disc in profile. Dorsum of petiole node smooth but the peduncle and sides reticulate; posterior spongiform strip of node lamellate and narrow. Postpetiole smooth in dorsal view, posteriorly with a thin spongiform strip which abuts a similar thin strip on the base of the first gastral tergite. Basigastral costulae very short, no longer on the tergite than the width of basal spongiform strip; gaster otherwise smooth. Dorsal surfaces of petiole, postpetiole and gaster with ground-pilosity similar to that described for the head, and with paired longer more erect hairs which are thick, sturdy and broadly clavate. Colour glossy brown, the legs with dense scale-like decumbent to appressed pilosity.

Paratype. TL 2.7, HL 0.60, HW 0.54, CI 90, ML 0.23, MI 38, SL 0.40, SI 74, PW 0.37, AL 0.75.

As holotype.

Type Material
Holotype worker, Cameroun: nr Yaounde, sample 2513 (G. Terron).

Paratype. 1 worker with same data but sample TS.

References based on Global Ant Biodiversity Informatics

 * Hita Garcia, F., G. Fischer, M.K. Peters, R.R. Snelling and H.W. Wagele. 2009. A preliminary checklist of the ants (Hymenoptera: Formicidae) of Kakamega Forest (Kenya). Journal of East African Natural HIstory 98(2): 147-165.
 * Ross S. R. P. J., F. Hita Garcia, G. Fischer, and M. K. Peters. 2018. Selective logging intensity in an East African rain forest predicts reductions in ant diversity. Biotropica 1-11.