Paratypes. Greece • 3 males; Lakonia, Skala env. [same as holotype]; 9 Jul. 1978; R. Batten leg.; NBCL, RMNH.INS.1485999 [genitalia illustrated], RMNH.INS.1486000, RMNH.INS.1486001 • 4 males; Arkadhia, Tripolis env.; 5 Jul. 1977; R. Batten leg.; NBCL, RMNH.INS.1485986, RMNH.INS.1485987, RMNH.INS.1485988, RMNH.INS.1485989 • 1 male; Messinia, 2 km N. of Kardamili; 6 Jul. 1977; R. Batten leg.; NBCL, RMNH.INS.1485985 • 2 males; Messinia, Pilos env.; 8 Jul. 1978; R. Batten leg.; NBCL, RMNH.INS.1485996, RMNH.INS.1485997 • 1 male; Korinthia, Neméa env.; 10 Jul. 1978; R. Batten leg.; NBCL, RMNH.INS.1485990 • 1 male; same data as preceding; HNHM • 1 male; Ilia, 4 km E. of Pirgos; 6 Jul. 1977; R. Batten leg.; NBCL, RMNH.INS.1485991 • 1 female; Fthiotis, 20 km S. of Lamia; 4 Jul. 1977; R. Batten leg.; NBCL, RMNH.INS.1485992 • 1 female; Aitolia, 5 km W of Navpaktos; 8 Jul. 1977; R. Batten leg.; NBCL, RMNH.INS.1485993 • 1 male; Aitolia, 11 km S of Agrinion; 8 Jul. 1977; R. Batten leg.; NBCL, RMNH.INS.1485998 • 1 female; Arta, 12 km NW of Arta; 8 Jul. 1977; R. Batten leg.; NBCL, RMNH.INS.1485994 • 1 male; Lakonia, 10 km N Sparti; 7 Jul. 1978; R. Batten leg.; NBCL, RMNH.INS.1485995 • 1 male, 1 female; Attica; E. Reitter leg.; syntypes of Mordellistenagemellata Schilsky, 1898; MNB • 1 female; “Parnass”; syntype of Mordellistenagemellata Schilsky, 1898; D. Krüper leg.; MNB.

Cyprus • 2 males, 3 females; Choirokoitia; 34.795833°N, 33.337500°E; alt. 186 m; 15 Jul. 2009; M. Mantič leg.; forest steppe, on flowers; MMCZ • 2 males; Pegeia, Coral Bay; 34.858333°N, 32.364167°E; alt. 9 m; 21 May 2017; M. Mantič leg.; forest steppe by sea, on flowers; MMCZ • 1 male, 6 females; Foinikaria, Germasogeia Reservoir; 34.755278°N, 33.093333°E; alt. 68 m; 27 Apr. 2018; D. Selnekovič leg.; secondary grassland, on Daucus; DSBS, DSBS15, DSBS16 • 1 male, 1 female; Kouklia env.; 34.666474°N, 32.628931°E; alt. 34 m; 9 May 2022; D. Selnekovič leg.; xeric grasslands on slopes, on Ferula; DSBS, DSBS609, DSBS610 • 1 male; Potamiou env.; 34.818289°N, 32.797439°E; alt. 677 m; 10 May 2022; D. Selnekovič leg.; road verge, orchards, on Daucus and Tordylium; DSBS, DSBS611 • 1 female; Pissouri; 34.653149°N, 32.715005°E; alt. 29 m; 12 May 2022; D. Selnekovič leg.; crop fields, slopes with xeric vegetation, on Ferula and Tordylium; DSBS • 3 males, 4 females; Avdimou env.; 34.675610°N, 32.758667°E; alt. 33 m; 13 May 2022; D. Selnekovič leg.; road verge, crop fields, on Daucus and Ferula; DSBS • 2 females; Kyrenia, Bellapais; 13 Jul 1939; H. Lindberg leg.; MZH, http://id.luomus.fi/GAC.38997. Greece • 6 specimens; Crete, Paralia Kouma; 35.352222°N, 24.298889°E; alt. 1 m; 16 Jul. 2012; M. Mantič leg.; sand beech, on flowers; MMCZ • 7 specimens; Crete, Paralia Preveli; 35.152778°N, 24.473333°E; alt. 7 m; 5 Jun. 2018; M. Mantič leg.; forest steppe, on flowers; MMCZ • 4 specimens; Crete, Lavris, 4 km W of Panormos; 35.417778°N, 24.648611°E; alt. 21 m; 1 Jun. 2018; M. Mantič leg.; forest steppe, on flowers; MMCZ • 1 female; Crete, Panormos env.; 35.416667°N, 24.689444°E; alt. 27 m; 30 May 2018; M. Mantič leg.; forest steppe, on flowers; MMCZ • 1 female; Crete, Orino Gorge, 1.8 km NW of Koutsoras; 35.045278°N, 25.932778°E; alt. 97 m; 19 May 2023; M. Mantič leg.; stram valley, on flowers; MMCZ • 4 specimens; Crete, Ierapetra; 35.014167°N, 25.768333°E; alt. 20 m; 16 May 2023; M. Mantič leg.; olive groves, on flowers; MMCZ • 1 male; Crete, Chochlakies; 35.146389°N, 26.246389°E; alt. 106 m; 10 Jun. 2023; M. Mantič leg.; olive groves, on flowers; MMCZ • 1 male; Crete, Kournas, Kourna lake; 30 Jun. 2002; A. Přidal leg.; NMPC • 1 male; Crete, Knossos; 1934; Mařan and Štěpánek leg.; NMPC • 2 specimens; Rhodes, Kalythiés env.; 36.326339°N, 28.187810°E; alt. 43 m; 26 May 2023; D. Selnekovič leg.; olive orchard, on Ammimajus and Helichrysum sp.; DSBS, DSBS715B, DSBS716 • 4 males, 1 female; Rhodes, Afantou env.; 36.311961°N, 28.189384°E; alt. 9 m; 26–30 May 2023; D. Selnekovič leg.; ruderal community, on Daucus sp.; DSBS • 3 males, 3 females; Rhodes, Kolympia; 36.259536°N, 28.131744°E; alt. 49 m; 28 May 2023; D. Selnekovič leg.; olive orchard, on Daucus and Ammimajus; DSBS, DSBS623 to DSBS626 • 11 specimens; Rhodes, Kolympia; 36.252222°N, 28.168056°E; alt. 15 m; 21 May 2011; M. Mantič leg.; forest steppe, on Apiaceae; MMCZ • 2 females; Rhodes, Kalythiés env.; 36.3202469°N, 28.1867823°E; alt. 14 m; 1 Jun. 2023; D. Selnekovič leg.; ruderal grassland with olive trees and shrubs, on Daucus sp.; DSBS. Italy • 4 males, 1 female; Campania, Naples, Camaldoli, 40.852285°N, 14.202138°E; alt. 142 m; 3 Jul. 2023; D. Selnekovič leg.; ruderal habitat, on Daucuscarota; DSBS, DSBS558, DSBS598, DSBS599 • 5 males; Sardinia, Sassari; 40.712163°N, 8.549854°E; alt. 207 m; 27 Jun. 2021; D. Selnekovič leg.; urban area, ruderal community along olive orchard and parking lot, on Daucuscarota; DSBS, DSBS700 to DSBS704 • 3 males; Puglia, Foggia, Vieste; 41.902976°N, 16.086091°E; alt. 60 m; 3 Jun. 2021; E. Ruzzier leg.; road verge, on Daucuscarota; ERPC • 1 male; Sicilia, Caltagirone; NMPC. Turkey • 1 male, 1 female; Mugla, Bodrum, Aspat; 24 May 2008; N. Gulpercin leg.; LEMT • 1 female; Mugla, Bodrum, Aspat; 7 Jun. 2008; S. Tezcan leg.; LEMT.

Mordellistenapeloponnesensis is characterised by antennomeres 1–4 being narrower than the following ones and by the presence of two short lateral ctenidia on the posterior tibia that are perpendicular to the dorsal edge of the tibia. This combination of characters is unique to the M.gemellata species group as defined by Ermisch (1956). Within this group, M.peloponnesensis (Fig. 1) is further distinguished by its black integument, including mouth parts and appendages, pale brownish to yellowish pubescence on the dorsal surface of the body, short antennal segments 5–10 (1.2–1.5× longer than wide), relatively large body size (TL 3.26–4.87 mm), long and narrow elytra (2.2–2.5× longer than wide), male tibia expanded at the base with a group of extended setae, and the characteristic shape of parameres (Fig. 1B, C).

The species most closely resembling M.peloponnesensis in terms of size, body shape, elytral length and width, and pubescence color are M.algeriensis Ermisch, 1966 (Algeria, Italy, and Tunisia), M.gemellata Schilsky, 1898 (Portugal, Spain), and M.pyrenaea Ermisch, 1966 (France, Spain). These species can be differentiated from M.peloponnesensis by distinct paramere shapes [see Selnekovič and Kodada (2022) for M.algeriensis; Ermisch (1966) for M.pyrenaea; and Ermisch (1963a) for M.gemellata]. Of these, M.algeriensis, recently reported from Sardinia (Selnekovič and Kodada 2022), is the only species with a range that partially overlaps with M.peloponnesensis. It differs from M.peloponnesensis not only in paramere shape but also in size: M.algeriensis has an EL/RPrL ratio of 5.89–6.42 and an EL/LPrL ratio of 5.21–5.54, while M.peloponnesensis has corresponding ratios of 6.84–8.61 and 5.65–7.38. Additionally, M.algeriensis can be distinguished by its subquadrate antennal segments 5–10 (~1.0× longer than wide), whereas in M.peloponnesensis, these segments are 1.2–1.5× longer than wide. Mordellistenaaureotomentosa Ermisch, 1966, described from Morocco, differs from M.peloponnesensis by its conspicuously light-yellowish and dense pubescence on the pronotum and elytra, and smaller, differently shaped parameres (Ermisch 1966). Mordellistenamaroccana Ermisch, 1966, found in Morocco and Tunisia, differs from M.peloponnesensis in the distinctly shorter and broader elytra: the elytral length/width ratio in M.maroccana is 2.0, while in M.peloponnesensis it is 2.2–2.5.

Measurements (in mm; ♂♂ N = 13, ♀♀ N = 10): TL: ♂♂ 3.26–4.52 (3.91 ± 0.45), ♀♀ 3.98–4.87 (4.41 ± 0.32); HL: ♂♂ 0.61–0.80 (0.72 ± 0.07), ♀♀ 0.72–0.85 (0.79 ± 0.05); HW: ♂♂ 0.65–0.84 (0.76 ± 0.07), ♀♀ 0.72–0.94 (0.84 ± 0.07); PL: ♂♂ 0.75–1.06 (0.91 ± 0.12), ♀♀ 0.88–1.19 (1.04 ± 0.10); PW: ♂♂ 0.73–1.06 (0.91 ± 0.12), ♀♀ 0.86–1.17 (1.05 ± 0.09); EL: ♂♂ 1.91–2.68 (2.28 ± 0.27), ♀♀ 2.35–2.82 (2.58 ± 0.17); EW: ♂♂ 0.77–1.14 (0.95 ± 0.12), ♀♀ 0.97–1.25 (1.12 ± 0.09); RPrL: 0.25–0.32 (0.30–0.02); LPrL: 0.31–0.41 (0.36 ± 0.03).

Body elongate (Fig. 1A), wedge-shaped, widest behind anterior third of elytra in males, around elytral mid-length in females. Dorsum moderately convex, venter strongly so. Entire body surface uniformly black, except for reddish-brown anteclypeus and tips of mandibles. Vestiture consisting of decumbent lanceolate setae; yellowish to brownish with purple sheen on dorsal surfaces, darkened towards elytral apices; yellowish on ventral surfaces, darkened along posterior margins of ventrites 3–5.

Head approximately as long as wide, HW/HL ratio: ♂♂ 1.02–1.12 (1.07 ± 0.03), ♀♀ 0.95–1.11 (1.07 ± 0.04), moderately convex dorsally, with highest point behind middle of eye length (lateral aspect); occipital carina rounded; integument weakly microreticulate, with small round setiferous punctures. Eyes broadly oval, approx. 1.4× longer than wide; posteriorly reaching to occipital margin; finely faceted; interfacetal setae longer than facet diameter. Anterior clypeal edge weakly convex. Labrum transverse, densely setose, anterior margin weakly convex. Antenna weakly serrate (Fig. 1A); antennomeres 1–4 shorter and narrower than following antennomeres; scape weakly conical, little longer than wide; pedicel cylindrical, approx. 1.5× longer than wide; antennomere 3 smallest, conical, as long as wide; antennomere 4 conical, approx. 1.7× as long as 3; antennomeres 5–10 in male 1.4–1.5×, in female 1.2–1.4× longer than wide, antennomere 5 longest; antennomere 11 oval, approx. 1.8× longer than wide; all antennomeres covered with decumbent trichoid sensilla, additionally, antennomeres 5–10 each with several long and erect trichoid sensilla apico-mesially. Galea moderately long, with spatulate sensilla and trichoid sensilla apically. Maxillary palpomere 2 subcylindrical, weakly expanded distally, similarly formed in both sexes except for distinctly longer trichoid sensilla on ventral surface in male; terminal maxillary palpomere scalene triangular, little wider in male than in female, mesial angle just behind mid-length; numerous decumbent and several erect trichoid sensilla over entire surface; apical sensory area with numerous short sensilla.

Pronotum approximately as long as wide, PL/PW ratio: ♂♂ 0.93–1.09 (1.00 ± 0.04), ♀♀ 0.96–1.02 (1.00 ± 0.02), widest before middle, strongly convex; surface microreticulate, densely covered with lanceolate setae, punctures larger than those on head; anterior edge convex in middle, anterior angles broadly rounded; lateral carinae strongly sinuate in lateral aspect; posterior edge sinuate, posterior angles rectangular in lateral aspect. Scutellar shield triangular, densely setose. Elytra moderately long and narrow, EL/EW ratio: ♂♂ 2.23–2.52 (2.40 ± 0.08), ♀♀ 2.18–2.42 (2.30 ± 0.07); apices separately rounded; surface microreticulate, densely covered with decumbent lanceolate setae, punctures coarser than those on pronotum. Hindwing fully developed. Metanepisternum approx. 4× longer than maximum width, narrowed posteriorly. Protarsomeres cylindrical, each little narrower than preceding one; protarsomere 1 as long as two following tarsomeres combined; penultimate protarsomere truncate distally, with apical edge weakly concave; each protarsal claw with three denticles; male protarsus with longer and thicker seta on ventral surface than female one. Mesotibia approx. 0.8× as long as mesotarsus. Mesotarsomeres cylindrical, each little narrower than preceding one; first mesotarsomere as long as two following tarsomeres combined. Metatibia with short subapical ctenidium and two lateral ctenidia nearly perpendicular to dorsal tibial edge, proximal ctenidium located around mid-length of tibia, distal one at around third quarter; outer terminal spur ca. 0.5× as long as inner one. Metatarsomere 1 with three ctenidia; metatarsomere 2 with two ctenidia; metatarsomeres 3 and 4 without lateral ctenidia.

Abdominal ventrite 5 with narrowly rounded apical edge. Pygidium long, conical, bent ventrad, narrowly truncate at apex, approx. 0.5× as long as elytra. Male sternite VIII with sinuate posterior edge, postero-lateral angles and medial portion moderately produced, with long trichoid sensilla (Fig. 1E); female sternite VIII produced at middle of posterior edge, with long trichoid sensilla around lateral edges (Fig. 1D), anterior median strut short, clavate. Phallobase forming sheath around penis; tubular part short; anterior struts approx. 5× as long as tubular part; dorsal apodeme strongly sclerotised. Parameres as in Fig. 1B, C: left paramere longer than right one, EL/LPrL ratio: 5.65–7.38 (6.33 ± 0.58), dorsal process dilated and obliquely subtruncate apically, with numerous trichoid sensilla, ventral process slightly shorter than dorsal one, tapering towards apex, median process short and wide, with cluster of sensilla campaniformia located along its dorsal edge; left paramere with dorsal process rather narrow, rounded apically, with trichoid and campaniform sensilla, ventral process slightly shorter than dorsal one, wide, bent dorsad, EL/RPrL ratio: 6.84–8.61 (7.67 ± 0.65). Penis long, narrow, weakly expanded before apex.

Females on average slightly larger than males. Males somewhat slenderer than females. Second maxillary palpomere with longer setae in males than in females. Terminal maxillary palpomere slightly narrower in females. Male protibia bears several elongate setae in proximal half, female protibia uniformly setose. Male protarsomeres with numerous thick setae ventrally.

Eighteen sequences of the COI gene barcoding region were generated and submitted to BOLD (www.boldsystems.org) and GenBank (www.ncbi.nlm.nih.gov/genbank/). Details on voucher specimens as well as accession numbers are listed in the Suppl. material 2.

Cyprus, Greece (mainland, Crete, Rhodes), Italy (southern part of the Italian peninsula, Sardinia, Sicily), Turkey (Fig. 2D).

Five individuals of M.peloponnesensis from Sardinia were sampled in June 2021 from the inflorescences of Daucuscarota L. (Apiaceae) in ruderal vegetation separating a parking lot from a small olive orchard in the urban area of Sassari. Three individuals from Vieste were collected on the inflorescences of D.carota in ruderal vegetation along a road. Five individuals from the vicinity of Naples were sampled in July 2023 on the inflorescences of D.carota in a ruderal habitat along a footpath on Camaldoli Hill. This area featured young secondary forest, orchards, and dry grassland communities. The following species co-occur with M.peloponnesensis in Italy: M.episternalis Mulsant, 1856, M.minima A. Costa, 1854, M.pseudorhenana Ermisch, 1977, M.purpurascens A. Costa, 1854, M.tarsata Mulsant, 1856, Mediimordabipunctata (Germar, 1827), Variimordabasalis (A. Costa, 1854), and Stenalia sp. In similar ruderal habitats along roadsides, secondary grasslands, and olive orchards, specimens of M.peloponnesensis were also collected on the islands of Rhodes (Greece) and Cyprus.