Cardiocondyla yoruba Rigato 2002

Seifert, Bernhard, 2024, A taxonomic revision of the ants of the Cardiocondyla wroughtonii group (Hymenoptera: Formicidae) with a checklist of the Cardiocondyla species of the world, Soil Organisms (London, England) 96 (2), pp. 113-144 : 136-137

Cardiocondyla yoruba Rigato 2002

[type investigation]

This taxon has been described from Niger. Investigated were three paratype workers on the same pin with the site equal to the holotype (see CASENT0901752 in www. antweb.org), labelled ‘ NIGERIA Ibadan, IITA.xi.87, T.Noyes’ (handwritten), ‘ Cardiocondyla yoruba n.sp. PARATYPI, det. F. Rigato 2002 ’ (handwritten), BMNH London .

Allmaterialexamined. Morphometricallyinvestigated were two samples with seven workers: the type sample plus a sample of four workers from Bondoukou / Ivory Coast .

Geographic range. Known so far only from West Africa: Ghana (by image evaluation of CASENT0901752), Ivory Coast and Niger.

Diagnosis: --Worker ( Tab. 2, Figs 6–10, key). Very small, CS 380 µm. Head very long, CL/CW 1.247.

Median third of anterior clypeal margin straight, median third of occipital margin slightly concave. Postocular distance large, PoOc/CL 0.459. Frons relatively narrow (FRS/CS 0.245); frontal carinae slightly diverging frontal of FRS level (FL/FR 1.063), caudal of FRS level parallel or slightly converging. Eye rather small, EYE/CS 0.240 and with scattered microsetae of 6–7 µm length. Scape very short, SL/CS 0.724. Metanotal depression shallow (MGr/CS 1.27 %). Propodeal spines short (SP/CS 0.120) and almost triangular in lateral view, their axis in profile deviating from longitudinal mesosomal axis by 25°, in dorsal view not diverging and their bases moderately wide (SPBA/CS 0.275). Petiole rather narrow and moderately high (PeW/CS 0.274, PeH/CS 0.334); in profile with a concave anterior face and semicircular dorsum; in dorsal view with an almost globular node, which is only slightly longer than wide. Postpetiole narrow and low (PpW/CS 0.427, PpH/CS 0.288); postpetiolar sternite anterolaterally with a rounded lobiform protrusion on each side which clearly elevates above the level of median surface of sternite; the surface of the sternite thus appearing deeply concave in frontal view. Postpetiole in dorsal view with a straight to slightly concave anterior margin and convex sides. Lateral parts of clypeus each with 2–3 rugulae, central part slightly carinulate-reticulate. Frontal laminae with weak microsculpture, consisting of an irregular mixture of microrugulate, foveolate and microreticulate elements. Whole vertex foveolate, mediad of the eyes with densely-arranged, flat-bottomed foveolae of 14–16 µm diameter. The largest foveolae show a well-demarcated but flat central tubercule of 6–8 µm diameter around the hair bases (Fig. 9). Whole surface of mesosoma foveolate-microreticulate; petiole strongly and postpetiolar tergite less strongly microreticulate. First gaster tergite with moderately long and dense pubescence (PLG/CS 6.89 %, sqPDG 3.86) and a more strongly developed microreticum, with the hair bases placed in microfoveolae of 4–6 µm diameter (Fig. 10). The microreticulum is an optical illusion in perpendicular view on the surface that is produced by the margins of roof-tile-like surface structures. Color: whole dorsum of gaster blackish brown and all remaining body parts yellowish or yellowish-brown.

Taxonomic comments. C. yoruba is inseparable in a PCA from C. yemeni considering all 16 NUMOBAT characters: the type samples of yemeni and yoruba and the non-type sample of yoruba from Ivory coast form a coherent cluster in a PCA ( Fig. 54 ). However, I stood back from synonymization of yoruba because of the very remote allopatric ranges, the blackish brown gaster not observed so far in the yemeni samples from Yemen and Oman and because of the stronger microsculpture of yoruba in particular on first gaster tergite. We have to wait if yoruba might be more convingly demonstrated as a separate cryptic species when plenty of samples were analyzed morphometrically or genetically.

Biology. The species is seems to follow other Cardiocondyla species by living in anthropogenously disturbed areas. As habitats were reported a grassy patch adjacent to a paved road in the urban center of Accra / Ghana and a path in the suburban area of Bondoukou / Ivory coast.

Figures

Figure 54. Principal component analysis of worker individuals considering all 16 morphometric characters. Triangles: Cardiocondyla weserka (grey: type of weserka, black: type of neferka, white: no type). Grey discs: syntypes of Cardiocondyla yemeni (Black rhombs: types of Cardiocondyla yoruba. White rhombs: C. yoruba sample from Comoe / Ivory coast). Black squares: Holotype and eight paratypes of Cardiocondyla heinzei n.sp. from Comoe / Ivory coast.