Holopyga dichroica Rosa, 2025

Rosa, Paolo, Felsner, Christian, Heim, René, Greeff, Michael, Michez, Denis & Bernasconi, Marco Valerio, 2025, The Palaearctic types of Chrysididae (Insecta, Hymenoptera) deposited in the Linsenmaier collection. Part 5. Elampini: genus Holopyga Dahlbom, 1845, Zootaxa 5565 (1), pp. 1-66 : 55-59

Holopyga dichroica Rosa , sp. nov.

urn:lsid:zoobank.org:act:A58BF7CB-D0AC-42B8-ADC2-26A6500BBB48

( Figs 43A–43I , 44A–44F )

Material examined. Holotype: ♂, Italy: Lazio, Viterbo province: Norchia , 42.3383 11.9497, 160m, 11.VIII.2022, leg. M. Selis (Type depository: MSNM) ( BIN: BOLD: AFA8977 ).

Diagnosis. Holopyga dichroica sp. n. is characterised by strong sexual dimorphism, with the male having a green head and mesosoma and a dorsally red metasoma ( Fig. 43 ), while the female has a blue head and mesosoma, with a red pronotum, mesonotum and metanotum ( Fig. 44 ). Other dimorphic characters are the elongate, ovoid shape of the third tergum in the female and slightly more acute and divergent temples in the male, which are dimorphic traits known in other Holopyga species. The male can be superficially confused with males of several species in the Western Palaearctic. However, the combination of the following characters allows for relatively easy identification: dense punctures on the second sternum ( Fig. 43I ); fine and dense punctures on the metasoma, without double punctation ( Fig. 43E, H ); simple and spaced, round punctures on the scutellum ( Fig. 43C ); the pronotum is greenish or lighter blue along the basal margin; the median area of mesoscutum is darker to black antero-medially ( Fig. 43C ); the elongate genital capsule with slender narrow gonostile and volsellae, is characterised by the greatly expanded digitus. The enlarged digitus, with different shapes, is also found in two related species, H. cypruscula Linsenmaier, 1959 and H. mlokosiewitzi Radoszkowsky, 1877 , and in an undescribed species from Iberia, currently under revision. The dense punctation of the second sternum distinguishes H. dichroica sp. n. from similar species such as H. lucida (Lepeletier, 1806) , H. chrysonota ( Förster, 1853) , H. austrialis Linsenmaier, 1959a and H. minuma Linsenmaier, 1959a . Its relatively small size (4.5–6 mm), light blue to greenish head and mesosoma, and round punctures on the scutellum differentiate it from the common H. generosa ( Förster, 1853) (normally larger, 6–9 mm; with a bluish to dark bluish head and mesosoma, and large, polygonal punctures without interspaces in H. generosa ). The simple sculpture of the metasoma distinguishes H. dichroica sp. nov. from H. amoenula Dahlbom, 1845 , H. cypruscula Linsenmaier, 1959a and its subspecies detrita and turcica, H. mlokosiewitzi hemisimpla Linsenmaier, 1959a , H. punctatissima Dahlbom, 1854 , H. turkestanica Mocsáry, 1909 , and species characterised by metasomal double punctation. The body colour pattern of the male separates this species from H. lucida , H. similis Mocsáry, 1889 , H. merceti , H. duplicata and all taxa related to H. lucida and H. cribrata which have two or more red segments on mesosoma. The identification of the female is easier for its unique body colour pattern; the head, mesosoma and anterior corner of pronotum are blue, while the rest of the pronotum, mesonotum and metasoma is dorsally flame-red. All other similar red species lack bluish anterior corners, whereas H. trapeziphora has a largely extended blue area laterally on pronotum ( Fig. 36 ).

Description. Male holotype. Body length 6.1 mm. Forewing length 3.9 mm.

Head. Frons with punctures of variable size, with polished interspaces; punctures on vertex and ocellar triangle smaller; ocellar triangle isosceles, with deep ocellar line connecting posterior ocelli; posterior ocelli with wide, polished lateral area; temple with small and scattered punctures; profile of temples subparallel in dorsal view; scapal basin polished on dorsal part and medially, deeply wrinkled at sides, with wrinkles sporadically reaching midline. Subantennal space short, less than 0.5× MOD. Clypeal apical margin bordered by narrow, darker rim. Mandible bidentate. OOL = 2.0× MOD; POL = 2.4× MOD; MS = 0.3× MOD; relative length of P:F1:F2:F3 = 1.0:2.1:1.3:1.1. Subantennal space = 0.6× MOD. Shortest distance between toruli = 1.0× MOD. Shortest distance between anterior margin of anterior ocellus and scapal basin = 2.0× MOD.

Mesosoma. Pronotum with double punctation; small, even punctures, separated by tiny punctures on interstices; mesoscutum with larger punctures, up to 0.8× MOD, irregularly shaped baso-medially, increasing in diameter basad, with polished interspaces and scattered dots in between; notauli fine, basally enlarged, as triangle; parapsidal lines deep; mesoscutellum with relatively smaller, rounded punctures and wider polished interspaces; mesopleuron acute, with dense punctures, larger on apical half than those on mesoscutum; metanotum with dense, irregular, and large foveate punctures, up to 1× MOD, longitudinally elongate anteriorly, with micropunctate interspaces at sides; propodeal teeth short, triangular, pointing slightly laterad.

Metasoma. Metasomal terga with even and minute punctures ( Fig. 43E, H ), equally spaced dorsally, 1–2 puncture diameter apart; apical margin of first tergum widely impunctate; apical margin of third tergum bearing narrow hyaline rim. Second and third sterna with dense, minute punctures ( Fig. 43I ). Genital capsule elongate, with slender, narrow gonostile and volsellae, characterised by greatly expanded digitus ( Fig. 43F, G ).

Coloration. Head and mesosoma green to bluish-green, with pronotal basal margin lighter, median area of mesoscutum darker to black anteriorly. Mandible brown; scape metallic blue, pedicel and flagellum brown. Tegula non-metallic brown; wings slightly smoky, veins brown.

Vestiture. Head and mesosoma with short, <1 MOD, whitish, and erectsetae; setae longer than 1 MOD on femora basally; metasoma with dense and short setae laterally; setae relatively dense on second and third sterna.

Female. Chromatically distinct from male, with pronotum, mesonotum and metanotum flame red. Other dimorphic characters include a more rounded head profile in frontal view ( Fig. 44B ); head in dorsal view with temples less angled and subparallel ( Fig. 44C ); mesoscutellum normally more sparsely punctate, though this may vary with denser punctures in some specimens. Metasomal punctation similar to male, with dense, even punctures on terga and dense, small punctures on sterna.

Variability. The size varies from 4.6 to 7.4 mm. In males, the mesonotum and scutellum are more or less sparsely punctate with mostly flat intervals, but in some specimens they may be significantly more densely punctate with narrow, sometimes ridge-like intervals. The head and mesosoma are normally green with darker to black area on median area of mesonotum anteriorly, but occasionally they can be green-bluish to light bluish, always with the black antero-median area. The extension of the digitus in the genital capsule may vary depending on preparation and can be more or less visible. In Figure 43F the genital capsule is inglobate in a drop of DMHF and mounted on a transparent plastic board, while in Figure 43G , the genital capsule is dry and mounted on a cardboard, giving a different optical shape of the capsule, digitus and volsella. In some cases, the digitus remains attached to the edeagus, remaining partially hidden. Expanded digiti can be found in other species, such as Holopyga cypruscula ( Fig. 12A ) and Holopyga mlokosiewitzi hemisimpla ( Fig. 25A ). Females size varies from 5.6 mm to 6.1 mm; the colour of the head and mesosoma laterally and ventrally can range from green to blue.

Molecular data. We barcoded over 150 specimens of European Holopyga including H. dichroica Rosa sp. nov. (listed as H. jurinei in BOLD) and related species such as H. austrialis Linsenmaier, 1959 , H. chrysonota ( Förster, 1853) , H. cypruscula Linsenmaier, 1959 , H. inflammata ( Förster, 1853) , H. lucida (Lepeletier, 1806) , H. minuma Linsenmaier, 1959 , and H. similis Mocsáry, 1889 . The results are presented in a syntetic phylogram ( Fig. 45 ) illustrating the major clades. COI barcodes of Holopyga dichroica (= H. jurinei sensu Linsenmaier in the tree) place H. dichroica in a distinct clade, here named the mlokosiewitzi aggregate, based on the name of the closest species with a similar genital capsule structure. The genetic distance between H. dichroica and H. lucida , the species with similarly coloured females, is 20.7%.

In the same clade of H. dichroica , H. cypruscula from Cyprus and an unknown cryptic taxon from Portugal and Spain are also grouped; these taxa will be discussed further in a separate paper on barcoding European species. The phylogenetic relationship between the two species is morphologically supported by similarities in male genitalia structure.The COI barcode of the Italian H.dichroica (here designated as the holotype of this species) clusters separately from the Iberian species initially identified as H. jurinei , with a substantial genetic distance of 7.8% and 9.4%. This barcode divergence is remarkably high, confirming the presence of a cryptic species. Morphological analysis of these Iberian specimens shows differences in genital morphology and metasomal sculpture. Since all H. jurinei specimens examined in this study were identified by Linsenmaier (NMLU), the first authors and other colleagues before genetic analyses, we cannot reliably separate them without an integrative study. Therefore, all examined specimens of H. jurinei sensu Linsenmaier are listed in the “Material examined” section rather than as paratypes.

Before Linsenmaier (1959a), female specimens of H. dichroica ( = jurinei sensu Linsenmaier ) were often misidentified with H. lucida (more specifically under the unavailable name H. gloriosa (Fabricius)) , while males were misidentified with H. generosa ( Förster, 1853) or other similar species. The genetic distance between H. dichroica and H. lucida is 20.7%, leaving no doubt about their lack of affinity. The genetic distance between H. dichroica and H. generosa is even greater, ranging from 22.9% to 24% (based on 30 specimens examined from across Europe). The different BINs (Barcode Index Number) for H. fervida and H. generosa in the phylogram ( Fig. 45 ) were already noted by Schmid-Egger et al. (2024) suggesting additional cryptic species that warrant further study in these molecular and integrative analyses.

Distribution. Western Palaearctic, from the Iberian Peninsula to Central Asia. We have examined material from Armenia, Austria, Bosnia-Herzegovina, Bulgaria, Czech Rep., Croatia, France, Greece, Hungary, Italy, Kazakhstan, Kyrgyzstan, Lebanon, Montenegro, North Macedonia, Romania, Portugal, Russia, Slovakia, Slovenia, Spain, Switzerland, Türkiye, Ukraine. All specimens were identified as Holopyga jurinei sensu Linsenmaier (1959a) by Linsenmaier himself (NMLU), by P.R., and by other colleagues listed in the Acknowledgments. These specimens are excluded from the type series because recent molecular analyses based on COI revealed that at least two Iberian specimens identified as H. jurinei sensu Linsenmaier actually belong to an undescribed taxon ( Fig. 45 ). A recent study on German Chrysididae ( Schmid-Egger et al. 2024) found that some common Holopyga species are associated with numerous BINs (Barcode Index Numbers), suggesting the possibility of multiple cryptic species, a scenario that may also apply to H. dichroica . Pending an integrative morphological and molecular revision of the European species, we do not designate as paratypes these specimens previously identified as H. jurinei using Linsenmaier’s (1959a) keys for the risk of having cryptic species hidden in the list. We selected as the holotype one specimen matching Linsenmaier’s species concept for H. jurinei ( Linsenmaier 1959a) .

Etymology. The specific epithet dichroica (adjective), from the Greek dikhroos (from di- ‘twice’ + khrōs ‘colour’), refers both to the different colouration of the male and female and to the dichroic colour of the female pronotum, which is red with blue anterior margins.

Hosts. Unknown.

Ecology. In the literature, this species (under the name H. jurinei ) is reported on Ferula communis ( Mingo & Gayubo 1986) ; Seseli tortuosum ( Mingo et al. 1988) ; Daucus carota , Pimpinella sp. , Foeniculum sp. , and Pastinaca sp. ( Rosa 2005) and it is listed as common on raspberry leaves, brambles, and various other shrubs at the edges of meadows ( Rosa 2006).

Remarks. More diagnoses, detailed descriptions of morphological characters, keys, colour photographs and even SEM photographs of Holopyga dichroica sp. nov. are found in Rosa (2006), Arens (2004) and Wiesbauer et al. (2020), always under the name H. jurinei .

Figures

FIGURE 12. Holopyga cypruscula cypruscula Linsenmaier, 1959a, holotype, male. A) Habitus, lateral view; inset: genital capsule. B) Head, frontal view. C) Head and mesosoma, dorsal view. D) Metasoma, latero-posterior view. E) Metasoma, posterior view. F) Metasoma, ventral view.

FIGURE 25. Holopyga mlokosiewitzi hemisimpla Linsenmaier, 1959a, holotype, male. A) Habitus, lateral view; inset: genital capsule. B) Head, frontal view. C) Head and mesosoma, dorsal view. D) Metasoma, latero-posterior view. E) Metasoma, dorsal view. F) Metasoma, ventral view.

FIGURE 36. Holopyga trapeziphora Linsenmaier, 1987, holotype, female. A) Habitus, lateral view. B) Head, frontal view. C) Mesosoma, dorsal view. D) Metasoma, latero-dorsal view. E) Habitus, dorsal view. F) Metasoma, ventral view.

FIGURE 43. Holopyga dichroica Rosa, sp. nov., holotype, male. A) Head, frontal view. B) Head, dorsal view. C) Head and mesosoma, dorsal view. D) Mesosoma, lateral view. E) Metasoma, latero-posterior view. F) Genital capsule (paratype, preserved in a glue of DMHF). G) Genital capsule (paratype, dry). H) Metasoma, dorsal view. I) Metasoma, ventral view.

FIGURE 44. Holopyga dichroica Rosa, sp. nov., paratype, female.A) Head and mesosoma, latero-dorsal view. B) Head, frontal view. C) Head, dorsal view. D) Head and mesosoma, dorsal view. E) Metasoma, dorsal view. F) Metasoma, ventral view.

FIGURE 45. Phylogenetic tree (maximum likelihood) of the European Holopyga aggregates based on mitochondrial COI gene. [H.dichroica Rosa(= H.jurinei sensu Linsenmaier) placed in mlokosiewitzi aggr., the most basal compared to the other European groups. Parnopes unicolor Gribodo not visible is the outgroup. Numbers adjacent to branches represent bootstrap support (values of <75 are omitted)].