Simopone schoutedeni Santschi

Bolton, Barry & Fisher, Brian L., 2012, Taxonomy of the cerapachyine ant genera Simopone Forel, Vicinopone gen. n. and Tanipone gen. n. (Hymenoptera: Formicidae) 3283, Zootaxa 3283 (1), pp. 1-101 : 38-39

Simopone schoutedeni Santschi

Simopone schoutedeni Santschi, 1923: 260 , figs 1a–c. Holotype worker, DEMOCRATIC REPUBLIC OF CONGO: Kamaiembi près Luebo, 17.ix.1921 (H. Schouteden) (MRAC) [examined].

WORKER. HL 0.98, HW 0.67, SL 0.32, EL 0.32, PW 0.51, AIIW 0.49, AIIL 0.52, AIIIW 0.60, AIIIL 0.64, WL 1.14, MFL 0.52, CI 68, SI 48, EL/HW 0.48, EP 1.00, AIIW/AIIL 0.94, AIIIW/AIIIL 0.94.

With head in full-face view the midpoints of the outer margins of the eyes just interrupt the outlines of the sides of the head. ES 0.28 and width of head across broadest part of eyes 0.68; minimum distance between eyes 0.32. Frontal lobes almost flat, only minutely raised away from level of clypeus. Frontal carinae extend back to level of anterior margins of eyes and are weakly divergent posteriorly. Cephalic dorsum with scattered broad, shallow punctures. Weak longitudinal ground sculpture also present between the eyes, but this fades out and vanishes behind the level of the posterior margins of the eyes. Leading edge of scape with a few setae, inclined toward the scape apex. Sides of head below and behind eyes with projecting short setae, inclined anteriorly. Cephalic dorsum with numerous short, curved setae that are mostly subdecumbent to decumbent, curved anteriorly near the posterior margin. Ventral surface of head with numerous short setae. Mesosoma in dorsal view narrowest across the mesonotum (maximum width 0.48), broadest across the propodeum (maximum width 0.54). Anterior margin of pronotum marginate rather than sharply carinate; the junction of anterior and dorsal surfaces marked by an angle and change of sculpture rather than a sharp carina. Propodeum with a fine weak carina between dorsum and declivity. Entire dorsum of mesosoma with broad, shallow punctures, denser on the mesonotum and propodeum than on the pronotum. Mesopleuron almost smooth, with just 1–2 punctures and a distinct transverse sulcus. Propodeal declivity appears smooth but is difficult to see because the anterior surface of AII is very close to it. In profile, dorsal surfaces of mesosoma and all abdominal tergites with numerous short, posteriorly curved setae that are subdecumbent to decumbent and densest on AIII and AIV. Standing setae are visible on right profemur and left mesotibia of holotype (obscured elsewhere on legs by glue and poor mounting). AII (petiole) in dorsal view longer than broad, with a weak transverse carina both anteriorly and posteriorly, the sides straight and parallel so that the width across the anterior margin the same as across the posterior margin. Dorsum of AII with large, shallow punctures whose diameters are greater than the distances that separate them. On AIII the punctures are slightly smaller than on AII but are even more crowded. On AIV punctures are even smaller but are still crowded, with their diameters greater than the distances between them. AIII longer than broad, AIV broader than long (width 0.68, length 0.62). Head capsule and body black; scapes and funiculi dull yellow; coxae and femora brown; tibiae and tarsi yellow.

Still known only from the holotype, schoutedeni is most likely to be confused with rabula , but this species differs in a number of critical characters, as mentioned under rabula above. Elsewhere in the group, schoutedeni may be confused with wilburi and vepres , because the size and prominence of its eyes (ES 0.28) are intermediate between these two larger-eyed species (ES 0.31–0.35) and the remainder of the group, in which the eyes are smaller (ES 0.20–0.26), and generally just fail to break the outline of the side of the head in full-face view. However, in schoutedeni the sides of AII (petiole), in dorsal view, are remarkably straight and parallel so that the width of the segment across its anterior carina is the same as across its posterior carina. In both vepres and wilburi the sides of AII in dorsal view are convex and diverge posteriorly, so that the width of the segment across its anterior carina is distinctly less than across its posterior carina.

The eleven species currently included in the schoutedeni group are best separated by the characters in the key, but at least one alternative system may be used. Seven of the eleven species have fine ground sculpture on the head between the eyes that is arranged into minute, irregular, roughly parallel longitudinal striolae or costulae, usually right across the interocular space. These minute costulae run between, and sometimes through, the broad shallow foveolate punctures that also occur in this area. Of the seven, fulvinodis is immediately isolated by its unique colour pattern and dryas by its long, narrow AIII and its small, relatively anteriorly located eyes. Of the remaining five species in this complex, schoutedeni is the only one to exhibit AII with parallel straight sides in dorsal view, so that the anterior and posterior widths of AII are almost exactly the same. In amana , annettae and wilburi the anterior width of AII is less than the posterior width, often obviously so, and all three are smaller than schoutedeni . S. wilburi has larger, more prominent eyes than amana and annettae , and annettae has AII broader than long, whereas in wilburi and amana AII is longer than broad.

The other four species lack conspicuous longitudinally arranged ground sculpture between the eyes, but small patches of disorganised microsculpture may be present, and even one or two tiny, isolated longitudinal striolae may occur. Of these, miniflava is quickly isolated by its uniformly yellow colour and brunnea has the punctures on the tergite of AIII reduced to widely separated pin-pricks, rather than the closely packed foveolate punctures that are more characteristic of the group. S. vepres is larger than occulta (e.g. HW 0.69 versus 0.49) and has larger, more prominent eyes. In addition, AII in vepres is broader posteriorly than anteriorly, whereas in occulta the two widths are almost exactly the same.

Material examined. Democratic Republic of Congo: Kamaiembi near Luebo (H. Schouteden).