Dioxys varipes De Stefani, 1887

13. Dioxys varipes De Stefani, 1887 View in CoL , sp. resurr.

Figs 13 A – F View Figure 13 , 14 A – D View Figure 14

Dioxys varipes De Stefani, 1887: 113, ♀ ♂ [ Italy: Sicily, RMNH, neotype by present designation]. View in CoL

Dioxys maroccanus Popov, 1936: 16, ♂ [ Morocco, ZISP, examined by photograph].

Dioxys falsificus Engel, 2023: 176, ♀ ♂ [ Spain, SEMC, examined by photograph] syn. nov.

Material examined.

Italy • Neotype: 1 ♀; Sicilia, Selinunte ; 22 Jun. 1966; P. M. F. Verhoeff leg.; RMNH; RMNH.INS.1663106 (Fig. 13 A – F View Figure 13 ) . Italy • 2 ♀; 35 km N Gela, NE Piazza Armerina ; 27 May 2002; J. Halada leg.; OÖLM • 1 ♀; Sicilia, Caltagirone ; 4–11 Jul. 1976; J. Timmer leg.; RMNH; ZMA.INS.5103998 ; Libya • 1 ♂; Cyrenaica, Brega [ Mars el Brega ]; 4 Mar. 1958; K. M. Guichard leg.; NMHUK • 1 ♀; Cyrene [ Shahat ]; 8 Jun. 1988; A. Četkovic leg.; RMNH; RMNH.INS.1663110 ; Morocco • 1 ♂; bor. [boreal = northern], River Rdat ; 15 Mat 1929; A. Birula leg.; V. Popov det.; ZISP (holotype of Dioxys maroccanus ; Fig. 14 A – D View Figure 14 ) • 1 ♀; Fès-Meknès, Ahermoumou, P 5407, immediately NW of Kassioua ; 900 m a. s. l.; 15 May 2022; T. J. Wood leg.; TJWC; WPATW 760-22 • 1 ♂; Fès-Meknès, Azrou, 4 km SWW of Bakrit, Cascades Bakrit ; 1650 m a. s. l.; 17 May 2022; T. J. Wood leg.; TJWC • 1 ♂; Fès-Meknès, Boulemane, 5 km SE, junction of R 503 and N 4 ; 1900 m a. s. l.; 19 May 2022; T. J. Wood leg.; TJWC; WPATW 761-22 • 1 ♂; Oudja, N-Jebel Fourhal, S-Ain Erreggada [Ain Reggada]; 500 m a. s. l.; 23 May 1994; M. Terzo leg.; RMNH; RMNH.INS.1660516 • 1 ♀; Souss-Massa, Tizi N’Test ; 16 Apr. 2024; D. Baiocchi leg.; MSVI • 1 ♀; Azrou, (zedernwälder) [ cedar forest ]; 1660 m a. s. l.; 17 Jul. 1975; A. W. Ebmer leg.; ZSM ; Portugal • 1 ♂; Algarve, Forte do Rato, Tavira ; 22 Apr. 2016; T. J. Wood leg.; TJWC • 2 ♂; Algarve, Montrigo ; 9 Apr. 1988; J. Teunissen leg.; T. J. Wood det. (det. D. varipes by M. Schwarz, 1989); RMNH.INS.1660521 ; RMNH.INS.1660523 • 1 ♂; Algarve, Praia do Barril, near Tavira ; 24 Apr. 2016; T. J. Wood leg.; TJWC • 1 ♂; Algarve, Praia do Cabeço, near Monte Gordo ; 26 Apr. 2016; T. J. Wood leg.; TJWC ; Spain • 1 ♀; Granada, Sierra Nevada, El Dornajo ; 1700 m a. s. l.; 29 Jun. 2021; T. J. Wood leg.; TJWC • 1 ♀; Madrid, Pozuelo del Rey , 2 km NW; 10 Jul. 2021; T. J. Wood leg.; TJWC • 1 ♀; Madrid, Rivas-Vaciamadrid, Canal de Manzanares to Camino de Uclés ; 19 May 2021; T. J. Wood leg.; TJWC • 1 ♂; Málaga, Arriate ; 30 May 1967; M. J. & J. P. Duffels leg.; RMNH; ZMA.INS.5103999 • 1 ♀; Málaga, Ronda , 10 km NE, A- 367; 25 May 2021; T. J. Wood leg.; TJWC • 1 ♂; Sevilla, Aznalcazar , S of Pinares de Aznalcazar; 21 May 2021; T. J. Wood leg.; TJWC • 1 ♀; Toledo, Toledo ; 10 Jul. 1969; P. M. F. Verhoeff leg.; T. J. Wood det. (det. D. pumilus ssp. varipes by Warncke); RMNH; RMNH.INS.1660522 • 1 ♀; Ronda ; 12 Jun. 1998; A. Kroupa leg.; ZSM • 1 ♀; Chipiona ; 8 Jun. 1998; A. Kroupa leg.; ZSM; • 1 ♀; Madrid ; 29 Jun. 1910; G. Mercet leg.; OUMNH ; Tunisia • 1 ♀; Tabarka , Tunis; 20 Apr. 1975; A. Mochi leg.; RMNH; RMNH.INS.1663111 .

Remarks.

Further to the comments made under D. cypriacus and D. pumilus , D. varipes can be considered as a distinct western species within the pumilus - group. As the type material of D. varipes is lost, designation of a neotype is desirable. In line with the conditions of article 75.3 (ICZN 1999), this neotype is needed to clarify the taxonomic status of western Mediterranean populations of D. pumilus sensu lato, and to act as the senior name for the western population which is newly considered to be specifically distinct. Specific characters allowing its recognition are specified in the identification key and in Section 10 on D. pumilus . The Hymenoptera part of the De Stefani collection is considered to be lost (e. g., Gusenleitner and Schwarz 2002; Cornalba et al. 2024), and hence no-one has been able to retrieve the original material of D. varipes (e. g., Warncke 1977). The selected specimen is from Sicily, the original terra typica ( De Stefani 1887), and morphologically conforms not only to the original description, but also to subsequent use of this species concept. Specifically, De Stefani describes the female as: “ Piccola, ugualmente punteggiata in tutto il corpo; la testa ed il corsaletto neri rivestiti di breve pelurie cenerina più marcata sul volto … L’addome è rosso ferrugineol al primo, secondo e terzo segmento, spesso il quarto segmento comunemente nero è mischiato irregolarmente a del color rosso … ” [Small, evenly punctured over the entire body, the head and mesosoma black and covered with short ash-coloured hairs, these more pronounced on the head … Metasoma red on terga 1–3, the 4 th segment is usually black but can be irregularly mixed with red …]. The body length was also given as 5 ½ – 6 ½ mm. This can only correspond to one species on the island of Sicily, namely the western sister taxon that is morphologically very close to D. pumilus . The selected neotype matches this description in the distribution of ashy hairs (Fig. 13 B – D View Figure 13 ) and the colouration of the terga (Fig. 13 E, F View Figure 13 ). The neotype is deposited in the RMNH collection.

Finally, it is necessary to deal with the taxon Dioxys falsificus Engel, 2023 . Engel described this taxon based on two females and two males (all from Algeciras in the extreme south of southern Spain, collected by K. M. Guichard), comparing it to D. pumilus . However, the description of this taxon is unsupported, and is based on material separated by D. Baker as “ undescribed ” and which was deposited in the Snow Entomological Collection after his death. Understanding the taxon therefore requires both an understanding of West Palaearctic Dioxys and an understanding of the species concepts used by Baker, Warncke, and Popov.

Baker did not publish on Dioxys in a strict sense (though see Baker 1998 for work on Dioxyini ), but he disagreed with Warncke’s creation of D. heinrichi from north-west Africa. Baker re-determined a male paratype of D. heinrichi (NHMUK) as D. maroccanus (Fig. 9 A View Figure 9 ; see Section 6), indicating that he did not accept Warncke’s synonymy of D. maroccanus with D. pumilus ssp. varipes . Examination of the holotype of D. maroccanus (Fig. 14 A – D View Figure 14 ), the synonymy of Warncke is correct, as the type specimen shows very short scutal hairs (shorter than the diameter of a lateral ocellus), and the genital capsule is typical (gonostyli apically slightly broadened but without laterally projecting triangular teeth). Baker was therefore de facto operating under the position that there was no name available for western populations of “ D. pumilus ” in Morocco or Spain. Considering that the type material of D. falsificus comes from Algeciras and was collected by Guichard in 1974, that Warncke (1977: 275) lists Algeciras within the distribution of D. pumilus ssp. varipes , and he was known to have revised Guichard’s material in the NHMUK, it is likely that Warncke inspected these specimens himself. They may have been taken by Baker from the NHMUK directly (temporary staff appointment 1981–1982; O’Toole 2006) before ending up in his personal collection which was then deposited in the SEMC.

Morphologically, the description of D. falsificus is based on very subtle morphological characters (female T 1 without a latitudinal carina, female apex of T 6 more broadly rounded, apical margin of S 5 with minute medial emargination, male S 6 with short longitudinal carina medially). Interpretation of the significance of these characters is difficult. Measurement of the width: length ratio of T 6 produces values of between 1.5–1.6: 1; specimens from the western Mediterranean have T 6 slightly broader compared to D. pumilus and D. cypriacus (Fig. 1 F View Figure 1 , specimen illustrated is from Morocco, see identification key couplet 7), but this value is so similar that it is difficult to use. In any case, D. falsificus does not seem to differ from this broader western Mediterranean trend. Examined female specimens of D. varipes from Morocco and Italy (Sicily), D. pumilus from Greece (Peloponnese) and Syria, and D. cypriacus ( Cyprus) show this subtle latitudinal carina on T 1, which seems absent on the Iberian specimens that could be inspected. However, when present, the carina is not strongly produced and often disappears into the surrounding punctures. It is not clear if Engel inspected any other specimens from Iberia or Morocco to investigate how consistent these putative characters are. When considered against the difference observed in the genital capsule between D. varipes and D. pumilus , this weak carina on T 1 is considered an inconsistent character with poor discriminatory power.

Moreover, Wood (2023) and Wood et al. (2024) presented COI barcode genetic data for “ D. pumilus ” (now considered under the name D. varipes ) from central and southern Spain (Madrid, Granada), southern Portugal (Algarve), and northern Morocco (Fès-Meknès). Sequences form a group with some genetic divergence, with average separation of 3.08 % (range 0.15–6.16 %). Whilst variation within Iberian populations was low (average 0.20 %), the highest divergence was actually seen between the two Moroccan specimens, at 6.16 %. Iberian sequences were therefore separated from the two Moroccan sequences by 4.51 % (range 4.41–4.56 %) and 3.50 % (range 3.34–3.65 %). Consequently, due to this variation, the Moroccan sequences do not form a direct sister group to Iberian sequences, with the two Moroccan sequences instead adjacent so that three Iberian sequences plus one Moroccan sequence are sisters, plus one additional Moroccan sequence as sister to this grouping (see Wood 2023: fig. 5).

Care should be taken in interpreting these results. The two Moroccan specimens come from the same province, were separated by just 65 kilometres, and were caught four days apart (see examined material). However, the specimen from Ahermoumou (WPATW 760-22) comes from a moderate elevation of 900 m a. s. l. in an area with Mediterranean climate and mixed wooded vegetation where olive is cultivated. In contrast, the specimen from Boulemane (WPATW 761-22) comes from high elevation at 1900 m a. s. l. from dry steppe desert. The observed higher genetic diversity in North African populations (based on the two sequences individuals) does not correspond to an apparent morphological difference in Morocco specimens themselves or between Moroccan and Iberian specimens. In the absence of morphological differences, North African and Iberian specimens are considered to be conspecific.

In this context, the name D. maroccanus is available to be applied to Iberian populations, at least in principle. Even if the extreme western populations of the taxon in Morocco and Iberia were found not to be conspecific with D. varipes populations on Sicily, D. maroccanus could be applied to specimens in the first instance from northern Morocco, the locus typicus. Since Engel’s (2023) paper does not mention the work of Popov once, and has not published information concerning morphological variation in D. pumilus sensu lato more broadly, D. falsificus is considered to not have been convincingly separated from D. maroccanus (the position that D. maroccanus is not synonymous with D. pumilus sensu Warncke being a key assumption inherent in following the unpublished position of Baker). Moreover, since no additional material outside of the four type specimens was revised (or if it was, this was not mentioned), convincing evidence for D. falsificus being consistently morphologically separated from populations from Sicily is lacking. Therefore, D. falsificus is synonymised with D. varipes syn. nov.

Distribution.

Portugal, Spain, Italy (Sicily), Morocco, Algeria, Tunisia, Libya * ( De Stefani, 1887; Popov 1936 as D. maroccanus ; Warncke 1977 partim, as D. pumilus ssp. varipes ; Kuhlmann et al. 2014 partim, as D. pumilus ; Baldock et al. 2018 as D. pumilus ; Bogusch partim, as D. pumilus ; Wood, 2023 as D. pumilus ).