Stenodynerus rufescens Giordani Soika, 1977

Selis, Marco, Cilia, Giovanni, Wood, Thomas J. & Soon, Villu, 2024, Taxonomic revision of the Stenodynerus fastidiosissimus species-group in Western Europe and North Africa (Hymenoptera: Vespidae: Eumeninae), Zootaxa 5418 (1), pp. 34-56 : 52

Stenodynerus rufescens Giordani Soika, 1977 stat. nov.

( Fig. 4C )

Stenodynerus fastidiosissimus rufescens Giordani Soika 1977: 168 , ♀—“ Cirenaica : Wadi Kut ” (holotype female NHMUK).

Diagnosis. Similar to S. fastidiosissimus , but differing in the following characters: black with ferruginous-red markings, apical bands on T1–T2 only, female clypeus with apical emargination 0.25× as deep as wide, male clypeus as long as wide with apical emargination 0.55× as deep as wide.

Material examined. LIBYA: Cyrenaica , Cirene, 1.V.1924, leg. C. Krüger, 1♂ ( MSNVE, OR292164 ) ; Cyrenaica , Wadi Kuf, 4–10.IV.1958, leg. K.M. Guichard, 1♀ ( MSNVE, paratype, OR292163 ) .

Distribution. Libya ( Giordani Soika 1977) ( Fig. 6A ).

DNA barcoding. COI-5P gene sequences were obtained from two specimens, including a topotypical paratype. The intraspecific sequence divergence of S. rufescens is 2.39%. The species is clearly separated from the other taxa considered in this study and supported by a bootstrap value of 100 ( Fig. 6B ). The lowest interspecific genetic distance exists between S. rufescens and S. fastidiosissimus , with a minimum of 26.56% (mean 28.19%).

Notes. Giordani Soika (1977) described this taxon as a subspecies of Stenodynerus fastidiosissimus (auct. non de Saussure, 1855), based on two females from Wadi al-Kuf. Examination of one paratype and of a male specimen from Cyrene, about 30 km NE of the type locality, showed that this taxon is closer to the true S. fastidiosissimus , sharing the same dense sculpture of S2 and similar shape of ventral lobe of aedeagus. We consider it a distinct species, due to the ferruginous-red markings, apical bands on T1–T2 only and the longer male clypeus with deeper apical emargination (0.55× as deep and wide) and longer and sharper lateral teeth. Genetic data support this treatment, with a genetic distance from S. fastidiosissimus of 26.56–32.05% (mean 28.19%).

Figures

FIGURE 4. A, Stenodynerus muelleri (Dusmet, 1917): habitus of male, habitus of female, head of male, head of female, flagellum of male, aedeagus in ventral and lateral view. B, female holotype of Stenodynerus gusenleitneri Giordani Soika, 1986: habitus in dorsal view and labels. C, Stenodynerus rufescens Giordani Soika, 1977: habitus of male, habitus of female, head of male, head of female, flagellum of male, aedeagus in ventral and lateral view.

FIGURE 6. A, distribution map of the Stenodynerus fastidiosissimus-group in Western Europe and North Africa; records out of the area considered in this study are omitted. B, phylogenetic tree (neighbor-joining) of the Stenodynerus fastidiosissimus-group based on the mitochondrial COI gene. Ancistrocerus gazella (Panzer) and three species belonging to other species-groups of Stenodynerus were used as outgroups. Numbers adjacent to branches represent bootstrap support (values of <75 are omitted).