Xenometra gallica Bernard 1957

Seifert, Bernhard, 2023, A revision of the Palaearctic species of the ant genus Cardiocondyla Emery 1869 (Hymenoptera: Formicidae), Zootaxa 5274 (1), pp. 1-64 : 28-29

Xenometra gallica Bernard 1957 [type investigation]

This taxon has been described from Pinsac / France. Investigated were 3 ergatoid male syntypes plus 5 workers and 5 gynes labelled “ Xenometra gallica F. Bernard ”, “Pinsac Lepointe 1951”, “Type”, “ANTWEB CASENT 0915399”, MNHN Paris. This taxon was erected because F. Bernard erroneously considered the ergatoid males found within a nest sample of C. elegans as gynes of a different socially parasitic species .

All material examined. Numeric phenotypical data were available in 50 samples (largely nest samples) with 119 workers. For details see supplementary information SI1, SI2. This material originated from France (39 samples) , Italy (7) and Spain (4).

Geographic range. Spain, southern France and Italy north to 47.5°N. In northern Italy east to 13.1°E and in southern Spain ascending to 930 m.

Diagnosis: --Worker ( Tab. 1 , Figs. 6–9 , key; pictures CASENT0904460, CASENT0908353, CASENT0915398 in www.antweb.org). Relatively large, CS 560 µm. Head moderately elongated, CL/CW 1.159. Postocular distance low, PoOc/CL 0.394. Scape rather long, SL/CS 0.842. Eye rather large, EYE/CS 0.252, with notable microsetae. Occipital margin suggestively concave to straight. Frons rather broad (FRS/CS 0.264), frontal carinae slightly converging immediately caudal of FRS level (FL/FR 1.051). Dorsal profile of promesonotum and of propodeum convex with a deep metanotal depression (MGr/CS 4.82 %). Spines rather short and acute (SP/CS 0.119), their axis in profile deviating by about 35° from longitudinal axis of mesosoma, their bases rather distant (SPBA/CS 0.267). Petiole rather wide and slightly lower than wide (PeW/CS 0.348, PeH/CS 0.330); in profile with a moderately long peduncle and a steep anterior slope of the node (about 65° relative to ventral profile). Postpetiole wide and moderately high (PpW/CS 0.580, PpH/CS 0.300), in dorsal view suggestively heard-shaped, with a concave anterior margin and convex sides; postpetiolar sternite convex. Head in overall impression mildly shiny. Whole vertex with shallow, feebly bicoronate foveolae of 16–18 µm diameter, foveolar distance on paramedian vertex smaller than foveolar diameter, near to eyes larger; the interspaces between foveolae shiny and in places with fragments of a very delicate microreticulum ( Fig. 9 ). Mesosoma shiny, with weakly developed microreticulum and microrugulae, a large number of foveolae present on dorsal promesonotum, their distance approximately equal to their diameter. Dorsal propodeum glabrous but with small foveolae and a very delicate microrugosity. Dorsum of waist glabrous, with scattered fragments of very fine microreticular structures. First gaster tergite glabrous. Pubescence on whole body long and dense, PLG/CS 7.92 %, sqPDG 3.95. Color of head, mesosoma, waist and gaster usually homogenously dark to medium brown; mandibles, scape, tibiae and tarsae yellowish brown.

Taxonomic comments and clustering results. The 85 available nest samples of the sister species Cardiocondyla elegans and C. dalmatica Soudek 1925 can be separated with a mean error of 1.2 % by the exploratory data analyses NC-Ward, NC-part.hclust, NC-part.kmeans and NC-NMDS.kmeans using the characters CS, CL/CW, PoOc/CL, EYE/CS, SL/CS, SP/CS, PeW/CS, PpW/CS, PeH/CS, PpH/CS, sqPDG, PLG/CS, MGr/CS and dFOV ( Fig. 133 ). A LDA using the same characters classified 97.8 % of 185 worker individuals of both species correctly. In the sample mean and when run in the LDA as wild-cards, the type samples of C. elegans , C. santschii , C. provincialis and C. gallica are allocated with posterior probabilities of 0.8443, 0.9166, 0.9972 and 0.9924 to the elegans cluster, whereas the lectotype of C. dalmatica is allocated with p=0.9961 to the dalmatica cluster.

Biology. For a condensed description of life history see Seifert (2018) and for details Lafrechoux et al. (1999, 2000), Lenoir (2006), Lenoir et al. (2007), Mercier et al. (2007), and Vidal et al. (2021).

Figures

FIGURE 133. Separation of nest samples of Cardiocondyla elegans (grey bars) and C. dalmatica (black bars) by NC-Ward, NC-part.hclust, NC-part.kmeans and NC-NMDS.kmeans clustering. White bars indicate outliers in NC-part.hclust. The mean classification error of the four exploratory data analyses relative to the controlling linear discriminant analysis is 1.2%. Fourteen phenotypic characters were considered. The bimodality within both species’ clusters represents an intraspecific dimorphism (Seifert 2016).

FIGURES 6–9. Cardiocondyla elegans; Fig. 6: head in dorsal view; Fig. 7 lateral view; Fig. 8: dorsal view; Fig. 9: head surface between inner eye margin and paramedian vertex. France: Brehemont-1.1 km E, 2010.07.15.