Stenodynerus difficilis MT Imselliet
Creators: name: Selis, Marco
name: Cilia, Giovanni
name: Wood, Thomas J.
name: Soon, Villu
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Eumenidae
Stenodynerus
Stenodynerus difficilis

description: Stenodynerus difficilis (Morawitz, 1867) stat. resurr.
(Fig. 1A, 2B)
Odynerus difficilis Morawitz 1867: 132, ♀, ♂ (in subgenus Leionotus)—[Russia] “ Gouvernement von Saratow ” (ZIN).
Odynerus proximus Morawitz 1867: 128, ♀—[Russia] “ Gouvernement von Saratow ” (lectotype ZIN).
Odynerus insularis André 1883: 232, ♀, ♂ (in subgenus Lionotus)—“Sicile; Tanger ” (lectotype MHNN [here designated]) [junior primary homonym of Odynerus insularis Smith, 1859].
Odynerus ferrugineitarsis De Stefani 1889: 232, ♀, ♂—[Italy] Sicily, five localities (types probably destroyed).
Odynerus maroccanus Dalla Torre 1889: 125. Replacement name for Odynerus insularis André, 1883.
Odynerus insulicola Dalla Torre 1894: 74. Replacement name for Odynerus insularis André, 1883. Junior primary homonym of Odynerus insulicola Blackburn in Blackburn & Cameron, 1886.
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 usually black, sometimes with yellow spots or posterior band, T1–T5 with yellow bands. In female: clypeus 0.9× as long as wide, apical teeth not carinate, apical margin shallowly emarginate, emargination 0.2× 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 with a short translucent lamella exceeding apical crenulate margin; punctures fine and sparse from head to T1, most interspaces narrow but flattened and shiny; lateral face of propodeum with fine striation and dense small punctures; punctures on T2 fine and dense, interspaces on disc up to 2× puncture diameter. In male: clypeus 0.9× 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 finely and sparsely punctured, interspaces flattened and longer than half puncture diameter; T3–T6 with fine and sparse punctures.
Material examined. LECTOTYPE Of ODYNERUS INSULARIS ANDRÉ: ♂, labeled “ S. Ninfa / 8-82 // coll. Piaget / ex André // Odynerus / insularis André // Stenodynerus / fastidiosissimus / difficilis (Mor.) ♂ / J.Gusenleitner,det.2000 // GBIFCH / 00093060 [QR code]” (MHNN-65-8637, GBIFCH00093060). CORSICA: Bastia, Moriani plage, 1 m, 25.VIII.2000, leg. A. Marata, 1♂ (MSVI, OR 292145). FRANCE: Cologne (Gers), Rec. Lescure, 26.IX–2.X.1966, leg. Nouvel, 1♀ (BGOF, OR 292161). ITALY: Abruzzo, Teramo, Morro d’Oro, 4–8.VIII.2022, leg. R. De Togni, 2♀ (MSNV); Belice, VIII.1882, leg. T. De Stefani, 1♀ (MHNN-65-8639, GBIFCH00093761, paralectotype of O. insularis); Calabria, Camigliatello, VII.1938, leg. Burlini, 1♂ (MSNVE); Emilia-Romagna, Casalborsetti, 4.X.2012, leg. G.L. Agnoli, 2♀ (MSVI); Emilia-Romagna, Pineta S. Vitale, Ca’ Vecchia, 30.VIII.2018, leg. G.L. Agnoli, 1♀ (MSVI, OR 292143); Emilia-Romagna, Val Sellustra, 250 m, 1.V.2017, leg. A. Degiovanni, 1♂ (MSVI); Lazio, Casale Cinelli, 200 m, 3.VIII.2019, leg. M. Selis, 1♂ (MSVI); Lazio, Casale Cinelli, 200 m, 23.VII.2021, leg. M. Selis, 1♀ (MSVI); Lazio, Civitavecchia, 27.VIII.2013, leg. M. Selis, 1♀ (MSVI); Lazio, Guidonia, Cave d’Argilla, 1.VIII.2022, leg. M. Selis, 1♂ (MSVI); Lazio, Maccarese, 30–65 m, 22.X.2019, leg. M. Selis, 2♂ (MSVI); Lazio, Roma, Tenuta della Cervelletta, 8.IX.1997, leg. M. Mei, 1♀ (MZUR); Lazio, Roma, Valle dell’Insughereta, 8.VIII.1993, leg. M. Mei, 1♀ (MZUR); Lazio, Roma, Valle dell’Insughereta, 21.VIII.1993, leg. M. Mei, 1♀ (MZUR); Lazio, Roma, Valle dell’Insughereta, 4.IX.1993, leg. M. Mei, 1♂ (MZUR); Lazio, Roma, Valle dell’Insughereta, 9.IX.1993, leg. M. Mei, 1♀ (MZUR); Lazio, Roma, Valle dell’Insughereta, 12.IX.1993, leg. M. Mei, 1♂ 1♀ (MZUR); Lazio, Roma, Valle dell’Insughereta, 31.VII.1994, leg. M. Mei, 1♂ (MZUR); Lazio, Roma, Valle dell’Insughereta, 7.VIII.1994, leg. M. Mei, 1♀ (MZUR); Lazio, Roma, Valle dell’Insughereta, 14.VIII.1994, leg. M. Mei, 1♂ (MZUR); Lazio, Roma, Valle dell’Insughereta, 9.VIII.1997, leg. M. Mei, 1♂ (MZUR); Lazio, Selciatella, 3.VIII.2019, leg. E. Pulvirenti, 1♂ (MSVI); Lazio, Sughereta di Pomezia, 8.VI.2014, leg. F. Turchetti, 1♂ (MSVI); Lazio, Sughereta di Pomezia, 15.VII.2014, leg. F. Turchetti, 1♂ (MSVI); Lazio, Tivoli, 14.VIII.1995, leg. M. Mei, 1♀ (MZUR); Lazio, Viterbo, Norchia, 160 m, 6.IX.2021, leg. M. Selis, 1♀ (MSVI); Lazio, Viterbo, Norchia, 130–160 m, 12.V.2022, leg. M. Selis, 1♀ (MSVI, OR 292142); Liguria, Ventimiglia, Ciaixe, 22.V.2021, leg. G. Abbo, 1♂ (MSVI); Molise, 10 km S Termoli, 24.VIII.1997, leg. J. Halada, 1♂ (OLML); Puglia, Cozze, 14.VI.2022, leg. S. Flaminio, 1♂ (MSVI, OR 292140); S. Ninfa, VIII.1882, leg. T. De Stefani, 1♂ (MHNN-65- 8638, GBIFCH049422, paralectotype of O. insularis); Sicilia, 1♂ (MSNVE); Sicilia, Capaci, 14.IX.1970, leg. M. Romano, 1♀ (MSVI); Sicilia, Capaci, 26.VI.2021, leg. M. Romano, 5♂ 1♀ (MSVI, 1♀ OR 292141); Sicilia, Cefalù, 3–12.VIII.1981, leg. G. Pagliano, 2♂ 1♀ (MSNVE); Sicilia, Siracusa, 21.IX.1970, 1♂ 1♀ (MSNVE); Toscana, Asciano, Lecceto, 13.VI.2013, leg. A. Petrioli, 1♀ (MSVI). MALTA: Imselliet, 5.VI.2021, leg. T. Cassar, 1♀ (MSVI, OR 292139).
Distribution. France (including Corsica), Italy (including Sicily), Malta (André 1883; Berland 1928; Blüthgen 1952; Borsato & Turrisi 2004; Cassar et al. 2022; DeStefani 1889; Giordani Soika 1932, 1942, 1953a; Giordani Soika & Borsato 1995; Gusenleitner 1981, 2000; Tussac 2007) (Fig. 6A). Distribution outside of the area considered in this study: Bulgaria, Croatia, Greece, Iran, Kazakhstan, Russia, Serbia, Turkey, Turkmenistan (Blüthgen 1959a, 1967; Castro & Dvořák 2009; Fateryga 2010; Fateryga et al. 2017; Giordani Soika 1970; Gusenleitner 1966, 2007, 2012; Kostylev 1928; Tobias & Kurzenko 1978).
DNA barcoding. COI-5P gene sequences were obtained from nine specimens from France, Italy, Malta, Croatia, and Greece. The mean intraspecific sequence divergence of S. difficilis is 1.47%, with Balkan specimens differing from more western specimens by 3.63–4.45% (mean 3.77%). 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. difficilis and S. fastidiosissimus, with a minimum of 22.12% (mean 24.09%).
Notes. For the reasons detailed below (see under S. fastidiosissimus), the populations of Stenodynerus from France, Italy and Malta that have traditionally referred to as S. fastidiosissimus fastidiosissimus (sensu Giordani Soika 1961) belong in fact to S. difficilis. The Sicilian populations, identical with those from peninsular Italy, were described independently as Odynerus insularis André, 1883 non Smith, 1859 (later given the replacement name O. maroccanus Dalla Torre, 1889) and O. ferrugineitarsis De Stefani, 1889, and these names were later synonymized under O. difficilis Morawitz, 1867 by Blüthgen (1939) and Gusenleitner (1981), respectively. Since no morphological differences could be found compared to the Balkan and Asian populations, the synonymy of O. insularis and O. ferrugineitarsis under S. difficilis is confirmed, and the latter is revalidated as a good species ranging from France and Italy to Central Asia. This treatment is additionally supported by genetic evidence: as mentioned above, Balkan specimens show an average genetic distance of 3.77% from more western populations, well below the mean interspecific distance of 28.48% observed in the fastidiosissimus -group.
Odynerus insularis André, 1883 was originally described based on specimens from Sicily and Morocco, therefore the original series was polytypic and certainly made of specimens belonging to both S. difficilis and one of the Moroccan species of the group, most probably S. fastidiosissimus. The location of the series of syntypes has been unknown until now. van der Vecht & Fischer (1972) suggested that the type series would be in Berlin, after some indications provided by Blüthgen (1939). Gusenleitner (2001a) examined the André collection in MHNN, finding four specimens (one ♀ and three ♂) of this taxon but not considering them as syntypic, and stating that the whereabouts of the types still needed to be clarified. One of the authors (MS) examined the series of specimens housed in the ZMB through photographs and could ascertain that the type series of O. insularis André is not there. The re-examination of the specimens in MHNN cited by Gusenleitner (2001a), however, demonstrated their belonging to the typical series. Although none of them is labeled as type, their data labels are handwritten by De Stefani, who sent the original series of O. insularis to André, according to the original description (André 1883). In particular, two males are labeled “S. Ninfa 8.82”, and comparison of the handwriting of the word “Ninfa” on the labels with the same word present on a list of De Stefani’s papers written by De Stefani himself showed a perfect correspondence, confirming the originality of the labels. Having confirmed that the specimens in MHNN are syntypes, one male from S. Ninfa, with catalog number MHNN-65-8637, is designated as lectotype of O. insularis André, 1883 non Smith, 1859 (Fig. 2B). Gusenleitner (2001a: 213) reported the female to come from “Behie”, but in fact the label reports “ Belice ”, a river in western Sicily.
Berland (1928) published several records of “ S. fastidiosissimus ” from across France, from the French Riviera in the south to Rouen in the north, but it is impossible to ascertain whether they refer to S. fastidiosissimus or S. difficilis without specimen examination, so they are therefore omitted from the distribution map.
description: Published as part of 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), pp. 34-56 in Zootaxa 5418 (1) on pages 38-39, DOI: 10.11646/zootaxa.5418.1.2, http://zenodo.org/record/10717928