Stenodynerus laborans ( Costa, 1882 )

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 : 43-45

Stenodynerus laborans ( Costa, 1882) stat. resurr.

( Fig. 3A )

Odynerus laborans Costa 1882: 23 , 37, ♂ (in subgenus Leionotus [!])—“ Sardegna ” [said to occur throughout the island] (? MZNF).

Odynerus punctuosus Ferton 1901: 130 , ♀, ♂—[ Corsica] “ Vivario ” (MNHN).

Diagnosis. This species can be recognized by the following combination of characters: gena 0.85–1.0 (♀) or 0.75– 0.85 (♂) × as wide as eye at bottom of ocular sinus, occipital carina shortly lamellate and not delimiting a furrow; parategula curved and pointing behind; lateral carinae of propodeum present, transition between dorsal and lateral faces marked by an irregular but distinct margin; scutellum black, T1–T2 with yellow bands. In female: clypeus as long as wide, apical margin shallowly but distinctly emarginate, emargination 0.25× as deep as wide; occipital carina high and distinctly curved in the middle; pronotal carina evenly rounded on sides, pronotal humeri obtuse in dorsal view; T2 without lamella exceeding apical crenulate margin; punctures coarse and dense from head to T1, interspaces reduced to narrow matte ridges; lateral face of propodeum with flat-bottomed polygonal cells and sparse small punctures; T2 with coarse and sparse punctures, interspaces up to four puncture diameters. In male: clypeus as long as wide, apical teeth sharp and long, apical emargination 0.3–0.35× as deep as wide and with a short translucent margin; F11 short and slim, reaching base of F 9 in lateral view, 2.8× as long as wide in dorsal view, not flattened, nearly circular in section; S2 sparsely punctured, interspaces wider than puncture diameter, except sometimes on posterior corners, punctures isolated and not forming series; apical part of aedeagus narrow, maximum width 2× as wide as basal width of median apodeme; ventral lobes of aedeagus short and subtriangular in lateral view, straight and slightly converging basally in ventral view; lateral apodemes angled in the middle; T1 coarsely and densely punctured, interspaces reduced to narrow irregular ridges; T3–T6 with coarse and dense punctures.

Material examined. CORSICA: San Giuliano , Pisonaccio, Bastia, 1m, 26.VIII.2017, leg. A. Marata, 1♀ ( MSVI, OR292150 ) . SARDINIA: Anglona , Nulvi, 13.VIII.1957, leg. E. Priesner, 1♂ ( MSNVE) ; Assemini ( CA), 10.IX.1999, leg. L. Fancello, 1♂ ( LFCI) ; Assemini ( CA), 4.VI.2006, leg. L. Fancello, 1♂ ( LFCI) ; Assemini , Foce Rio Cixerri, 25.VII.2021, leg. L. Fancello, 1♂ ( LFCI) ; Capo Falcone , 7.VIII.1968, leg. S. Erlandsson, 1♂ ( MSNVE) ; Capoterra , Santa Lucia, V.2021, leg. L. Fancello, 1♀ ( MSVI) ; Capoterra , Santa Lucia, 1.VII.2021, leg. L. Fancello, 1♀ ( MSVI, OR292147 ) ; Foce fiume Tirso, 20.V.2006, leg. L. Fancello, 1♂ ( LFCI) ; Gavoi , lago Gúsana, 40.116722 9.2105, 640 m, 25.VIII.2021, leg. D. Sechi, 1♀ ( DSCI) ; Gennargentu , Aritzo, 1400m, 4.VIII.1974, leg. Hartig, 1♂ ( MZUR) ; Isola Asinara , Cala Arena, VII.1903, leg. S. Folchini, 1♂ ( MSNVE) ; Isola di S. Pietro, 4–20.VII.1994, leg. M. Mei, 5♂ 6♀ ( MSVI, MZUR) ; Isola di S. Pietro, Carloforte, 25.VI.1954, leg. L. Ceresa, 1♂ 2♀ ( MSNVE) ; Musei , 22.VII.1974, leg. Hartig, 1♂ ( MZUR) ; Nurri ( NU), 16.VI.2003, leg. L. Fancello, 1♀ ( LFCI) ; Olbia , Punta Ceraso, 17.V.1994, leg. M. Mei, 1♂ ( MZUR) ; Oristano , Tharros, 21.IX.1964, leg. K.M. Guichard, 1♀ ( MSNVE) ; Ozieri ,

1.VII.2010, leg. L. Fancello, 1♂ ( LFCI) ; Sant’Anna Arresi, Portu Su Trigu, 2.VIII.2021, leg. L. Fancello, 1♂ ( MSVI) ; Sarroch ( CA), 2.VII.2003, leg. L. Fancello, 1♀ ( LFCI) ; Sassari, Ardara, 5.V.2018, 40.574520 8.791822, leg. A. & G. Franzini, 1♂ ( MSVI, OR292148 ) ; Sorgono, leg. Krausse, 1♂ ( MSNVE) ; Villaputzu, Quirra, spiaggia di Murtas, 20.IX.2021, leg. L. Fancello, 1♂ ( MSVI, OR292149 ) ; Villasimius, VI.1975, leg. Bouĉek, 1♂ ( MSNVE) .

Distribution. Corsica, Sardinia ( Berland 1928; Borsato 2006; Costa 1882; Ferton 1901; Giordani Soika & Borsato 1995; Grandi 1954; Guiglia 1938; Gusenleitner 1981, 2000; Nadig 1933) ( Fig. 6A ).

DNA barcoding. COI-5P gene sequences were obtained from four specimens from Sardinia and Corsica. The intraspecific sequence divergence of S. laborans is 0.00%. 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. laborans and S. muelleri , with a minimum of 25.00% (mean 25.07%).

Notes. The first worker to consider Stenodynerus laborans as a subspecies of S. fastidiosissimus was Berland (1928), who considered Odynerus punctuosus as a variety of O. fastidiosissimus , and this treatment was followed by most subsequent authors ( Blüthgen 1939; Borsato 2006; Giordani Soika1951; Gusenleitner1981, 2000). Gusenleitner (1981) proposed a subspecific status for this taxon (under S. fastidiosissimus auct. non de Saussure, 1855) due to the absence of differences in the male genitalia, sculpture, vestiture and coloration other than on metasoma. While it is true that S. laborans and S. difficilis share similar male genitalia, vestiture, and sculpture, Gusenleitner overlooked all the remarkably constant differences here mentioned in diagnosis and key. These, combined with a genetic distance of 26.03–30.38% (mean 27.43%), support the recognition of S. laborans as a distinct species.

Gusenleitner also mentioned the presence of specimens with several yellow bands in Sardinia and Corsica, and specimens with reduced yellow bands in the mainland. The extensive material we have examined proves otherwise, as all Sardinian specimens show two yellow bands (except one male from Capo Falcone having a hint of yellow band on T3) and mainland specimens show at least four complete bands; the same was observed by Borsato (2006). Three species coexist in Corsica, S. difficilis , S. fastidiosissimus and S. laborans , with constant morphological and genetic differences and no transitional forms. However, the records of S. difficilis and S. fastidiosissimus are based on single specimens only and could represent accidental importation.

Figures

FIGURE 3. A, Stenodynerus laborans (Costa, 1882): habitus of male, habitus of female, head of male, head of female, flagellum of male, aedeagus in ventral and lateral view. B, Stenodynerus montanus Selis, sp. nov.: 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).