Cleptes britannicorum Rosa, 2024, sp. n.
Creators: name: Rosa, Paolo
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Chrysididae
Cleptes
Cleptes britannicorum

description: Cleptes britannicorum sp. n.
(Figures 9A, C, 10 A–C, 11 A, D, 12 A–D, 13A, D, G, I, J)
Diagnosis
Cleptes britannicorum sp. n. is similar to Cl. nitidulus (Fabricius, 1793) and Cl. semicyaneus Tournier, 1879 in habitus and colour pattern. It can be separated by the vertex without postocellar foveae (Figure 10A, 10J) vs vertex with deep, large postocellar foveae in Cl. nitidulus (Figure 10G, M), narrow postocellar foveae in Cl. semicyaneus (Figure 10D). Temples, the posterior area between eye and occipital area, convergent, with oblique margin (Figure 10A, J), vs unmodified in Cl. nitidulus (Figure 10G, M) and more convergent and oblique in Cl. semicyaneus (Figure 10D). Male face in frontal view with rounded profile l/w = 1.25, without distinct facial pits, with two wide and shallow depressions (Figure 10B, A), face of Cl. semicyaneus distinctly enlarged l/w = 1.45 (Figure 10E), with two small, distinct facial pits. Posterior propodeal projections [= propodeal angles] slightly divergent, pointed and outward directed (Figure 11A), similar to Cl. nitidulus (Figure 11C) and right angled in Cl. semicyaneus (Figure 11B). Second and third terga with sparse, even punctation (Figure 13A, D), vs dense punctation on the second and dense and double on the third in Cl. nitidulus (Figure 13C, F) and sparse in Cl. semicyaneus, with punctures increasing in diameter towards the posterior margin of the third tergum (Figure 13E). Colour pattern: male femora metallic blue, meso- and hindtibiae dark brown (Figure 9A) vs meso- and hindtibiae yellow in Cl. nitidulus (Figure 9B), forelegs yellow, meso- and hindfemora with a weak, median bluish reflection, tibiae yellow in Cl. semicyaneus (Figure 11F); female forelegs entirely yellow, meso- and hindfemur dark brown (Figure 9C) vs all femora dark brown in Cl. nitidulus (Figure 9D) and all legs yellow in C. semicyaneus (Figure 14A); female head with metallic violet reflections, more or less diffuse on face (Figure 10J, K) vs black without metallic reflections in Cl. nitidulus (Figure 10M, N), occasionally with weak metallic violet to light bluish reflections. Female mesoscutum with greenish to violet reflections (Figure 9C), normally black in Cl. nitidulus (Figure 9D), occasionally with weak metallic reflections. In both sexes of Cleptes britannicorum sp. n. the third tergum is largely dark brown to black, sometimes only postero-laterally, with blue to violet reflections more or less expanded; the fourth tergum is blue to violet (Figure 12A, G), vs without or with weak lateral reflection in Cl. nitidulus (Figure 13C, H), blue metallic on fourth and fifth terga in Cl. semicyaneus male (Figure 13B) and only on fourth in female (Figure 13D).
Material examined
Holotype: ♂, ENGLAND: Lancs. Nr. Southport, Ainsdale N. N. R. 24.vi.1976 W. Kenneth-Booker/ ♂ Cleptes nitidulus (F.) Det. G. R. Else 1976/ Cleptes nitidulus ♂ (Fabricius, 1793) det. B. WiŚniowski 2012 (NHMUK). Paratypes: ENGLAND: 1♀, same labels as the holotype (NHMUK); 1♀, England (PRC); 1♀, zonata /oval white label/ 1937 in B.M. Coll. under C. nitidulus F. (NHMUK); 1♀, 1937 in B.M. Coll. under C. nitidulus F. (NHMUK); 1♂, 1937 in B.M. Coll. under C. semiauratus L. (NHMUK); 1♀, 50 58/ 1937 in B.M. Coll. under C. nitidulus F. (NHMUK); 1♂, This is the true [word unclear, probably referred to the blue colour of the metasomal apex] F. Smith/ 1937 in B.M. Coll. under C. nitidulus F. (NHMUK); 1♂, Oxwich, Gower Glam 11.-16.vi.[19]55 E.A. Fonseca/E.A: Fonseca coll. BMNH (E): 1988–212; Cleptes 1 ♂ nitidulus (F.) det. J.C. Felton. 1974 (NHMUK); 1♂, Sandscale Dunes Lancashire 15.6.[19] 58 JMN/ Cleptes nitidula (Fab) JMN det 1958 (NHMUK) (all specimens housed at NHMUK identified as Cleptes nitidulus by B. WiŚniowski 2012). 2♂, 1♀, e coll. J.C. Dale. CW. Dale Pres 1906 C.W.D. (OUMUK); 1♀, Lowestoft Aug 71/ex coll. F.D. Morice/Standing over Cleptes nitidulus (Fabricius, 1793) OX.UNI. MUS.NAT. HIST. (OUMNH); 1♀, Wallacey 28.viii.’06/ Cleptes ♀ nitidulus / Standing over Cleptes nitidulus (Fabricius, 1793) OX.UNI. MUS.NAT. HIST. (OUMNH); 2 Cleptes nitidula F. Det. in Coll. Ent. Club, Inst’d 1826. Pres.’d 1927 by Club to Hope Coll./Standing over Cleptes nitidulus (Fabricius, 1793) OX.UNI. MUS.NAT. HIST. (OUMNH); 1♀, Standing over Cleptes nitidulus (Fabricius, 1793) OX.UNI. MUS.NAT. HIST. (OUMNH); 1♂, Hightown Mereyside VC59 SD295033, England, 1.7.1996, leg. J. T. Burn (Burn private collection, Durham). SCOTLAND: 1♀, Findhorn: beach MORAY; Scotland 1977 July G. van Rossem, Museum Leiden ex coll. Verhoeff, Cleptes semicyaneus Tournier, 1879 ♀ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH). FRANCE: 1♂, Plouhernel (France-département 56), 16.vi.2004, top of the beach, leg. GRETIA (Nico Schneider collection, Luxembourg); 1♂, Saint-Rémy-des-Landes (France-département 50) 4.vi.1954 leg. H. Chevin (Nico Schneider collection, Luxembourg); 3♀♀, Chapelle-sur-Loire Port d’Ablevois (47.238°N, 0.187°E) 12.vii.2017 leg. Christian Cocquempot (TUZ); 1♀, idem, 13.vi.2017 (TUZ); 1♀, idem, 30.vi.2017 (TUZ); 2♂♂, idem, 13.viii.2017 (TUZ); 1♀, Loiret: Orléans, secteur Duit (ponts Joffre-Thinat); 11.VIII.2014, Labo Eco-Engomologie leg., 47.895°N, 1.905°E, banc de sable sur bords de Loire (centre ville) (R. Le Divelec private collection, Mons). BELGIUM: 1♀, Belgique Heist 21.vi.[18]76, Collection Dr. J. Tosquinet, Cleptes nitidula F. dét. J.Tosquinet, Cleptes nitidulus Fab. Rev. A. Housiaux 1922 (RBINS). NETHERLANDS: 1♂, Zeewolde FT 5998 zanddep. Stichtse br. J.de Rond 24.vi.1993 (PRC); 1♂, Zeewolde FT 5998 zanddep. Stichtse br. J.de Rond 24.vi.1993 (PRC); 1♀, Noordwijk a Z. (Ho.) (duin) 14.vii.1941 leg. PMF Verhoeff, Cleptes Ltr. nitidulus F. ♀ Linsenmaier det. 1963, Museum Leiden ex coll. Verhoeff, Cleptes semicyaneus Tournier, 1879 ♀ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♀, Nederland Meijendel N.v. Bierlap 12.vi.1963 Ph. Pronk, ♀, Cl. semicyan. ♀ elegans Mocs. det. Móczár 1978, Cleptes semicyaneus Tournier, 1879 ♀ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♂ and 1♀, Museum Leiden HOLLAND Exc Zeeuws Vlaanderen Clinge nr Hulst 14.vi.1966 Ph Pronk, Cl. semicyaneus Tourn. det. Móczár 1978, Cleptes semicyaneus Tournier, 1879 ♀ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♂, Museum Leiden HOLLAND (Z.H.) Den Haad, Bosjes van Poot, sand-pit near Houtrust, 13.vii.1972 Ph. Pronk (72.040), on leaves of Populus spec., Cleptes nitidulus (F.) ♂ det van Lith, Cleptes semicyaneus Tourn. ♂ det. Móczár 1994, Cleptes semicyaneus Tournier, 1879 ♂ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♂, Weesp 2.vii.1978 L. Bansberg, Cleptes nitidulus F. ♂ V. Lefeber 1980, Museum Leiden ex coll. Verhoeff, Cleptes semicyaneus Tournier, 1879 ♂ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♂, Nederland-Fl Almere 20–22.vi.1993 V. Lefeber, Cleptes nitidulus F. ♂ V. Lefeber 1983, semicyaneus, Museum Leiden ex coll. Verhoeff, Cleptes semicyaneus Tournier, 1879 ♂ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♂, Museum Leiden HOLLAND exc Terschelling (Fr.) nr Rijsplak 2.vi.1969 ca. 53é24 ʹ N – 5°15 ʹ E C.v. Heijningen, Cl. semiauratus (L.) ♂ det. C.v. Heijningen, Cleptes semicyaneus Tourn. ♂ det. Móczár 1994, Cleptes semicyaneus Tournier, 1879 ♂ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♂, same locality, 14.vii.1967 W. Planjer, Cl. semicyan. ♂ elegans Mocs. det. Móczár 1978, Cleptes semicyaneus Tournier, 1879 ♂ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♂, Herpen 13.vi.1936, Cleptes semiauratus L. ♂ det. H. Teunissen, Cleptes semicyaneus Tournier, 1879 ♂ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♂, Herpen 13.vi.[19]36 Boven Klaver, Cleptes semiauratus L.? ♂ det. 1947 P.M.F. Verhoeff, Museum Leiden ex coll. Verhoeff, Cleptes semicyaneus Tournier, 1879 ♂ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♂, Museum Leiden Nederland (Z.H.) bij vliegv. Ypenburg 23.vi.1962 Ph. Pronk, Cl. semicyaneus Tourn. ♂ det. Móczár 1978, Cleptes semicyaneus Tournier, 1879 ♂ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♂, Nederland (Z.H.) N.v. Voorschoten 24.vi.1964 Ph Pronk, Cl. semicyaneus Tourn. ♂ det. Móczár 1978, Cleptes semicyaneus Tournier, 1879 ♂ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♂, Emmen 7.vii.[19]91, Cleptes semi-auratus L. ♂, Cleptes semicyaneus Tournier, 1879 ♂ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♂, NEDERLAND NH Schoorl 3.v.1990 B. V. Lefeber, Cleptes nitidulus F.? ♂ V. Lefeber 1990, Museum Leiden ex collection V. Lefeber Rec. 2004, Cleptes semicyaneus Tournier, 1879 ♂ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♀, NEDERLAND-NH. Buitenveldert 19.v.1971 B. V. Lefeber, Cleptes nitidulus F. ♀ V. Lefeber 1970, Museum Leiden ex collection V. Lefeber Rec. 2004, Cleptes semicyaneus Tournier, 1879 ♀ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♀, NEDERLAND-NB St. Michielsgest. 3.vii.1971 B. V. Lefeber, Cleptes nitidulus F. ♀ V. Lefeber 1970, Museum Leiden ex collection V. Lefeber Rec. 2004, Cleptes semicyaneus Tournier, 1879 ♀ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♀, Fransen Rotterd., Mus. Leiden, Cleptes nitidulus F. ♀, Cleptes semicyaneus Tourn. ♀ det. Móczár 1994, Cleptes semicyaneus Tournier, 1879 ♀ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH); 1♀, Blevs (N.B.) 30.v.[19]45 Cl. nitidulus ♀, Cleptes semicyaneus Tournier, 1879 ♀ det. T.M.J. Peeters 1996 Opgen. voor EIS-NL (RMNH).
Description
MALE (holotype). Body length 6.7 mm, fore wing length 3.9 mm.
Head. Vertex sparsely punctate with interstices between punctures 2–6 PD wide and polished; vertex without postocellar foveae (Figure 10A); punctation denser on face, interstices between punctures 1–2 PD, with polished interstices; face without facial pits (Figure 10B), with two wide and shallow depressed areas (Figure 12A). Temples convergent, with oblique margin (Figure 10A). Head colour metallic blue with some greenish tint. Proximal half of mandible metallic green, distal half brown.
Scape green, rest of antenna dark brown, nearly black, covered with dense white sensilla. Pubescence on head whitish, setae about 1 × MOD long. Subantennal space narrow, less 1 × MOD; apical margin of clypeus medially continuous; OOL 2.0 × MOD; POL 1.5 × MOD; MS 1.0 × MOD; relative lengths of P:F1:F2:F3 = 1:1.8:1.1:1.1.
Mesosoma. Pronotum sparsely and shallowly punctate; posterior edge simple, without row of foveae. Mesonotum sparsely and shallowly punctate with wide, polished interstices. Mesopleuron densely punctate, with wide mesopleural pit, covering large upper surface. Metascutellum small, subrectangular, shallowly punctate; laterally with wide metanotal fovea and metascutellar trough, both without distinct metanotal ridges. Metapectal-propodeal complex with trapezoidal metapostnotum, with rugose irregular carinae and two anterior and impunctate areas; metapleuron arm, the anterodorsal extension of metapleuron located anterolateral to prespiracular propodeal area, well defined and composed by transverse foveae (Figure 11A); posterior propodeal projections [= propodeal angles] apically acute and outwards oriented. Mesosoma colour metallic blue with some greenish tint, propodeum metapostnotum and propodeum partly violet. Pubescence on mesosoma white. Femora blue, mid and hindtibia medially brown. Wing venation typical for Cleptes.
Metasoma. First tergum polished anteriorly, with sparse, shallow dots posteriorly before the polished apical margin (Figure 13A, D). Second tergum with sparse, even, small punctures, deeper laterally; apical margin polished. Third tergum with sparse, even, small and deep punctures, distinctly sparser medially, with small, sparse and shallow dots; apical margin polished. Fourth and fifth terga with similar punctation. Genital capsule as in Figure 12B, C, similar to Cleptes nitidulus (Móczár 1997a), apex of gonocoxa more rounded, larger and apically pointed volsella, penis valvae slender and elongate; eighth sternite (Figure 12D) elongate compared to Cl. nitidulus. White pubescence on first and second terga becoming longer and thicker postero-laterally; third and fourth terga covered by long, thick setae. First, second and third terga anteriorly testaceous; third tergum posteriorly brown with more or less extended violet reflections laterally; fourth entirely blue to violet; fifth black with weak median blue reflection.
FEMALE (paratype). Similar to male for sculpture. Head with rosy to violet tint; pedicel, first and partially second flagellomere testaceous, rest of antenna brown (Figure 10J, K). Pronotum and forelegs testaceous, mesoscutum black with green reflections, medially violet. Metanotum, metapostnotum and propodeum blue with greenish reflections. Mid and forefemora dark brown, tibiae testaceous. Metasoma coloured as in the male. Pubescence whitish, longer at sides except for the following characteristics: relative lengths of P:F1:F2:F3 = 1:1.1:0.5:0.5.
Variation
Paratypes vary from 4.7 to 6.8 mm. The face can be flat or with two lateral depressions, more or less wide and deep, without distinct and deep facial pits. The punctation on the third metasomal segment is deeper or denser in some Dutch male specimens. Male specimens from the continent show the third tergum dorsally black with weak metallic reflection, or black with metallic reflections laterally and antero-laterally orange.
Distribution
United Kingdom (England, Scotland), France, Belgium, Netherlands. Material from Germany, Denmark, Poland and Central Europe (listed by Móczár 1997a) must be validated. WiŚniowski (2015) did not examine any Polish specimen of Cleptes semicyaneus, whereas J. Paukkunen (pers. comm.) found two male specimens from Stettin (currently Szczecin) collected on 27 June 1937 by A.R. Paul in the collection of the Helsinki Museum (Finland). They show the same colouration as Cl. britannicorum sp. n.; however, they have denser and deeper body sculpture and one has the head similar to Cl. semicyaneus. I exclude them from the type series, waiting for confirmation by molecular analyses. The female specimen from Scandinavia, illustrated in Paukkunen et al. (2015), probably refers to another taxon. In fact, the shape of the head in dorsal view appears different, with extended temples, similarly to Cleptes semicyaneus. At the moment, I do not consider these specimens to belong to Cl. britannicorum sp. n., waiting for molecular analyses. The barcode of a Norwegian specimen is already available on BOLD.
In addition, records from Southern Europe must be validated. Strumia (1995) included Cleptes semicyaneus in the checklist of the Italian species without specifying a locality and depository. However, in the subsequent checklist of the Italian Fauna with distributional data (Strumia 2005), the species is no longer mentioned. Regarding the Swiss fauna, WiŚniowski (2015) reported that Linsenmaier (1997) identified Cl. semicyaneus as Cl. chevrieri Frey-Gessner, 1887. However, specimens identified as Cl. chevrieri in Linsenmaier’s volume (1997), as well as specimens in his collection and the type specimens deposited at MHNG, are conspecific with Cl. splendidus (Fabricius, 1794).
Cleptes britannicorum sp. n. has always been present in the UK in modern times and was not recently introduced. It was previously confused with Cleptes nitidulus (Morgan 1984). Its current status is uncertain due to confusion with Cleptes nitidulus. While De Rond (2022) classifies the species as very rare and endangered, it appears to be relatively common in Britain and the Netherlands based on the examined material. De Rond (2022) attributes the classification of rarity and endangerment to the decreasing availability of habitats, particularly in river areas where the species has been recently observed, due to canalisation.
Host. De Rond (2022) suggests that larvae of Nematinae (sawflies) living on willows in pioneer vegetation on moist sand are probable hosts. The species was found in Flevoland sand areas as soon as seedlings of narrow-leaved willow species dense thickets began to form in young sandy areas. The sawfly larvae’s cocoons are underground, and Cleptes females were observed walking on the sand or burrowing. Ødegaard et al. (2009) proposed a sawfly of the family Tenthredinidae living on creeping willows (Salix repens Linnaeus) as the probable host for the Scandinavian form. A female in nature was photographed in the Netherlands at Meijendel, Helmduinen (ZH) on 20 May 2016 by Ruud van Middelkoop (https://waarneming.nl/photos/10904073/). The same image was used by De Rond (2022) in his report on insects of sea dunes of the Kennemer Dunes National Park (North Holland Province). In 2020 de Rond collected in this park a few specimens fallen in a pan trap, and in a Malaise trap. One paratype was collected on Populus leaves. Also the French specimen collected at Orléans by R. Le Divelec and by Christian Cocquempot were found on sandy banks of the Loire river.
Flight period
June to August (Paukkunen et al. 2015 for Cleptes semicyaneus).
Etymology
The name is dedicated to British entomologists who illustrated and/or recognised this species as distinct from Cleptes nitidulus and Cl. semiauratus, although they never properly described it.
Curtis (1824: plate 724) illustrated a female of Cleptes britannicorum sp. n. under the name of Cl. nitidulus. Despite the beautiful colour illustration showing a specimen with a violet head and metallic blue third and fourth metasomal segments, the description of both sexes of Cl. nitidulus is a mixture of characters of Cl. nitidulus and Cl. britannicorum sp. n. For instance, features like ‘the 3d segment, excepting the base and the following, bright blue, green, or purple’ for the male and ‘Head and thorax cupreous [...] abdomen as in the male’ for the female are considered diagnostic for Cleptes britannicorum sp. n.
Probably Leach identified and labelled this taxon as Cleptes zonata in the collections of the British Museum (Stephens 1829, fig. 13I). The name zonata by Stephens is unavailable as it was simply listed as a synonym of Cl. nitidulus (Stephens 1829).
Morice (1896, p. 118) recognised that under the name Cleptes nitidulus there were two species and sent three doubtful specimens to du Buysson for his opinion:
but I find two males of nitidula mixed with those of pallipes in Smith’s collection. The three males which are placed there under nitidula are correctly determined; but they are by no means normal specimens, having exceedingly dark legs, and the apex of the abdomen much more vividly blue than is usual in this species. M. du Buysson has kindly examined these insects at my request, and confirms e in naming the whole five nitidula, Fab.
The three male specimens sent to du Buysson belong to Cleptes britannicorum sp. n. It should be noted that, in the same years (du Buysson 1891–1896), the French entomologist stated that he did not know Cleptes semicyaneus, and placed it in the ‘ Espèces que n’ai pu examiner ’ along with the original description given by Tournier.
Comments
The description of a new species in the nitidulus group (subgenus Leiocleptes according to Móczár’s classification) is not unexpected. According to Juho Paukkunen (pers. comm.) the group includes another potentially undescribed species based on different COI barcode. On BOLD a published barcode of Cleptes ‘ semicyaneus ’ from Norway is available; unfortunately, there are no available barcodes of Cleptes semicyaneus from Sarepta (currently Volgograd), the topotypical locality of this species, or from other southern Russian localities. I am in any case confident that Cleptes britannicorum sp. n. is distinct and easily identifiable based on morphological characters.
Specimens of Cleptes britannicorum sp. n. from Western and Northern European countries were previously identified as Cleptes semicyaneus (Niehuis 2001; Peteers 2004; Paukkunen et al. 2015; WiŚniowski 2015) based on Móczár’s (1997a, 1997b 1998) revision of the genus Cleptes. However, Móczár’s interpretation of Cleptes semicyaneus apparently includes at least three different species: the typical Cleptes semicyaneus (synonym Cl. elegans Mocsáry, 1901), Cl. britannicorum sp. n. and a third taxon known as Cl. nitidulus erdosi Móczár, 1951 (see below).
In the search for an available name already published for Cleptes britannicorum sp. n., no success was found. Laporte (in Guérin-Méneville 1829 –1844) illustrated Cleptes thoracicus [pl. 68, illustration dated 1835]. As noticed by Guérin-Méneville himself in the text (p. 421), Cl. thoracicus is the female of Cl. nitidulus Fabricius, 1793. However, no description, type locality, type series and type depository were provided for Cleptes thoracicus and from the line drawing, it cannot be determined whether Cleptes thoracicus is potentially conspecific with Cl. britannicorum sp. n. Instead of a nomen dubium, I consider the name Cl. thoracicus unavailable as it was firstly published as a junior synonym and never made available by subsequent authors.
Mocsáry (in Mocsáry and Szépligeti 1901) described Cleptes elegans based on a female from Russia, Kazan (Figure 14). Móczár (1997a) synonymised Cleptes elegans Mocsáry, 1901 with Cl. semicyaneus and I followed this interpretation (Rosa et al. 2017b). Cleptes elegans can be considered to be the female of Cl. semicyaneus for the two small facial pits; narrow foveae lateral to posterior ocelli; sparse metasomal punctation on second tergum; body colour pattern; head with rosy to violet reflections, fourth tergum blue and legs entirely yellow. However, some diagnostic characters may argue against this interpretation, such as the profile of the head in frontal view (Figure 14C) and the double punctation on the third tergum. These could be sexual dimorphic characters, but a re-evaluation of the sex association should be done based on more material available from southern Russia.
Móczár (1997a) also synonymised Cleptes nitidulus erdosi Móczár, 1951 with Cl. semicyaneus. However, Cleptes nitidulus erdosi lacks the facial pits and the narrow ocellar fovea; its head is metallic green to light blue in contrast to the rosy to violet colouration of Cl. britannicorum sp. nov. Additionally, the metasoma lacks metallic reflection; mid- and metafemora are dark brown, and the punctation on third tergum is dense. Given these distinguishing characteristics, I consider Cl. erdosi to be a taxon distinct from Cl. semicyaneus and Cl. britannicorum sp. n., but also distinct from Cl. nitidulus for the metallic reflection on head and the sparse punctation on the second tergum. Also in this case, a re-evaluation is needed after examining more material.
Two additional names were considered synonyms of Cleptes nitidulus, and potentially related to Cleptes britannicorum sp. nov.: Cleptes fallax Mocsáry, 1889, and Cl. femoralis Mocsáry, 1890. They were examined to avoid the description of a synonym. Mocsáry (1889) described Cleptes fallax based on an unknown number of specimens collected at Sarepta, and deposited in the Saussure collection, now housed at MHNG. du Buysson (1891–1896) synonymised this species; Móczár (1962) later designated a lectotype, which is invalid as it was a non-syntypic specimen collected in Hungary (Budapest) (Rosa et al. 2017b). A specimen labelled as type is still conserved at MHNG, and it apparently belongs to a different species, closely related to Cleptes nitidulus based on the posterior ocellar foveae and the dense punctation of the metasoma. However, for accurate placement, the examination of genitalia is needed. Cleptes femoralis, described from Turkey and known from Greece and the Caucasus, has been revalidated by Móczár (1997a); it belongs to the nitidulus group but it is closely related to Cleptes splendidus (Fabricius, 1794) rather than to Cl. nitidulus.
description: Published as part of Rosa, Paolo, 2024, A journey through the history of the British Chrysididae (Hymenoptera): unexpected taxonomic problems, new records and description of a new species, pp. 840-889 in Journal of Natural History 58 (25 - 28) on pages 855-865, DOI: 10.1080/00222933.2024.2352186, http://zenodo.org/record/13219813