Italy, Ischia, Serrara env., 40.72138°N, 13.88305°E; steep slopes with grassland communities, ca. 550 m alt. (Fig. 7).

Holotype: italy • male; Ischia, Serrara env.; 40.72138°N, 13.88305°E; ca. 550 m alt.; 30 Jun 2019; D. Selnekovič leg.; steep slopes with grassland communities, on inflorescences of Apiaceae; GenBank: OM680978; SNSD. Paratypes: italy • 9 males, 8 females; same data as for holotype • 23 males, 11 females; Ischia, Serrara env.; 40.71666°N, 13.88638°E; 517 m alt.; 29 Jun 2019; D. Selnekovič leg.; ruderal habitat on road verge, on inflorescences of Daucuscarota; GenBank: OM680977, OM680997, OM680998, OM681002, OM681019 to OM681021; SNSD.

Mordellistenaplatypoda is included in the M.micans species group as defined by Batten (1977) on the basis of the following characters: the four first antennomeres are narrower and shorter than the following ones (Fig. 3D); hind tibia besides the subapical ctenidium with four lateral ctenidia that are more or less perpendicular to the dorsal edge of the tibia (Fig. 4A); only the first two metatarsomeres with lateral ctenidia (Fig. 4A); punctation of elytra not conspicuously coarse; metatibial spurs black. A rather unique character that separates the species from most of its congeners is the shape of pro- and mesotarsomeres, which are flattened and expanded. The entire male mesotarsus and the female pro- and mesotarsus are dilated apically (Figs 4D, E, 5A, B). Similarly formed tarsi are present in M.rugipennis Schilsky, 1895 and M.latitarsis Batten, 1983, both of which differ from M.platypoda in the entirely black vestiture and shape of the genitalia. Furthermore, M.platypoda is characterised by its large body dimensions (TL: ♂♂ 4.58–5.64 mm, ♀♀ 4.84–6.02 mm). Similarly large body is present within the M.micans species group only in M.purpurascens A. Costa, 1854 (TL: ♂♂ 4.27–5.76 mm, ♀♀ 4.32–5.78 mm), M.hirtipes Schilsky, 1895 (TL: ♂♂ 4.13–5.16 mm, ♀♀ 3.69–4.77 mm), and M.austriaca Schilsky, 1898 (TL: ♂♂ 3.85–5.37 mm, ♀♀ 3.67–5.33 mm). The latter species is separated from M.platypoda by almost square antennomeres 5–10, the lateral pronotal sides straight in the lateral aspect, the posterolateral pronotal angels obtuse, the elytra shorter (EL/EW ratio ≤ 2.2), and the genitalia differently shaped.

Mordellistenaplatypoda most closely resembles a sympatric species M.purpurascens but differs in paler vestiture, weakly expanded male second maxillary palpomere, with few long setae (Fig. 3A) compared to strongly expanded, with numerous long setae in M.purpurascens (Fig. 3C), weakly expanded male protibia, with few inconspicuous extended setae (Fig. 4B) compared to strongly expanded, with conspicuous long setae in M.purpurascens (Fig. 4C), protarsus expanded in both sexes and distinctly dilated apically in females (Fig. 5A, B) compared to weakly narrowed apically in M.purpurascens (Fig. 5C), elytra longer, with EL/EW ratio: ♂♂ 2.31–2.64, ♀♀ 2.22–2.40 compared to ♂♂ 1.97–2.23, ♀♀ 1.83–2.15 in M.purpurascens, and parameres distinctly shorter and differently shaped (Figs 4G, H, 5B; EL/LPrL ratio: 7.09–8.59, EL/RPrL ratio: 9.67–12.08) than in M.purpurascens (EL/LPrL ratio: 4.42–5.84, EL/RPrL ratio: 5.57–6.94; see Selnekovič and Kodada 2019: fig. 7). Mordellistenatenuicornis Schilsky, 1899 is separated from M.platypoda by the presence of two or three lateral ctenidia on the third metatarsomere, antennomeres 5–10 ca. 2.0× longer than wide, and pygidium distinctly longer and more slender.

The results of the COI gene analyses show the close relationship of M.platypoda with M.tarsata Mulsant, 1856, with p-distances of 8.21–8.97%. The two species are easily distinguished by the colouration of the dorsal vestiture, which is black with a greenish lustre in M.tarsata compared to yellowish in M.platypoda (Fig. 1), the presence of two lateral ctenidia on the third metatarsomere in M.tarsata compared to the absence of lateral ctenidia on the segment in M.platypoda, the presence of a conspicuous cluster of long setae in the proximal portion of the male protibia in M.tarsata compared to few elongated setae in in M.platypoda, and the different shape of the parameres.

Measurements (in mm; ♂♂ n = 33, ♀♀ n = 21): TL: ♂♂ 4.58–5.64 (5.25 ± 0.26), ♀♀ 4.84–6.02 (5.56 ± 0.31); HL: ♂♂ 0.81–1.01 (0.92 ± 0.05), ♀♀ 0.84–1.06 (0.97 ± 0.06); HW: ♂♂ 0.94–1.17 (1.07 ± 0.05), ♀♀ 0.95–1.19 (1.10 ± 0.06); PL: ♂♂ 0.98–1.25 (1.14 ± 0.06), ♀♀ 1.06–1.33 (1.22 ± 0.08); PW: ♂♂ 1.10–1.46 (1.32 ± 0.08), ♀♀ 1.19–1.57 (1.42 ± 0.10); EL: ♂♂ 2.75–3.50 (3.18 ± 0.18), ♀♀ 2.92–3.67 (3.37 ± 0.19); EW: ♂♂ 1.13–1.42 (1.31 ± 0.07), ♀♀ 1.25–1.54 (1.45 ± 0.08); RPrL: 0.27–0.32 (0.29–0.01); LPrL: 0.36–0.43 (0.40 ± 0.02).

Body elongated, wedge-shaped, widest in anterior half of elytra (Fig. 1). Dorsum slightly convex, venter strongly so. Entire body surface uniformly black, except for reddish brown anteclypeus. Vestiture consisting of decumbent lanceolate setae (Fig. 4F); yellowish, darkened before elytral apices and along posterior margin of ventrites 4 and 5.

Head large, transverse, moderately convex dorsally, with highest point behind middle of eyes (lateral aspect), HW/HL ratio: ♂♂ 1.09–1.23 (1.16 ± 0.03), ♀♀1.01–1.23 (1.13 ± 0.05); occipital carina convex; integument weakly microreticulate, weakly iridescent, with small round setiferous punctures. Eyes broadly oval, vertical diameter ca. 1.3× horizontal diameter; posteriorly reaching to occipital margin; finely faceted; interfacetal setae longer than facet diameter. Anterior clypeal edge weakly convex. Labrum transverse, densely setose, anterior edge weakly convex. Antenna weakly serrate (Fig. 3D, E); antennomeres 1–4 shorter and narrower than following segments; scape cylindrical, little longer than wide; pedicel cylindrical, little longer than scape; antennomere 3 little longer than wide, expanded distally; antennomere 4 little longer than 3; antennomeres 5–10 in both sexes 1.6–1.7× as long as wide; antennomere 11 oval, ca. 2.2× as long as wide; all antennomeres covered with decumbent sensilla chaetica; antennomeres 5–10 each with several long and erect sensilla trichoidea apico-laterally (Fig. 3D, E). Galea short, with spatulate sensilla and sensilla chaetica apically (Fig. 3A, B). Lacinia with numerous sensilla chaetica apically and row of sensilla chaetica along mesal margin (Fig. 3A, B). Maxillary palpomere 2 subcylindrical, weakly expanded distally, in males little wider and with somewhat longer sensilla chaetica than in females (Fig. 3A, B); terminal maxillary palpomere scalene triangular, mesal angle in middle or in anterior half, numerous decumbent sensilla chaetica and several erect sensilla chaetica over entire surface, several sensilla placoidea before distal margin.

Pronotum 1.1–1.2× as wide as long, widest behind middle, moderately convex; surface microreticulate, densely covered with lanceolate setae, punctures larger than those on head; anterior edge convex in middle, anterolateral angles broadly rounded; lateral carinae sinuate in lateral aspect; posterior edge sinuate, posterolateral angles rectangular in lateral aspect. Scutellar shield triangular, densely setose. Elytra widest between first and second quarter, EL/EW ratio: ♂♂ 2.31–2.64 (2.43 ± 0.07), ♀♀ 2.22–2.40 (2.32 ± 0.05); apices separately rounded; surface microreticulate, densely covered with decumbent lanceolate setae, punctures coarser than those on pronotum. Hindwing as in Fig. 6A. Mesoventral process about as wide as mesotibia. Metaventral discrimen apparent. Metanepisternum ca. 2.3× longer than greatest width, narrowed posteriorly. Metendosternite as in Fig. 6C. Protibia ca. 1.1× longer than protarsus; in males weakly expanded proximally and with few inconspicuous extended setae (Fig. 4B). Protarsus expanded and flat in both sexes, weakly dilated distally in females (Figs 4D, E, 5A, B); protarsomere 1 little shorter than three following tarsomeres combined; penultimate protarsomere weakly expanded distally, with apical edge concave; each protarsal claw with four denticles. Mesotibia ca. 0.8× as long as mesotarsus. Mesotarsus dilated distally in both sexes; first mesotarsomere nearly as long as three subsequent tarsomeres combined. Metatibia with short subapical ctenidium and four lateral ctenidia nearly perpendicular to dorsal tibial edge, proximal ctenidium often rudimentary (Fig. 4A); outer terminal spur ca. 0.75× as long as inner one. Metatarsomere 1 with four or five lateral ctenidia; metatarsomere 2 with two lateral ctenidia; metatarsomeres 3 and 4 without lateral ctenidia (Fig. 4A).

Abdominal ventrite 1 longer than ventrite 2; ventrite 5 with arcuate apical edge. Pygidium long, conical, narrowly truncate at apex, EL/PygL ratio: ♂♂ 1.75–2.03 (1.87 ± 0.06), ♀♀ 2.12–2.35 (2.21 ± 0.06). Male tergite VIII deeply emarginate on posterior edge, setose apically (Fig. 6F); female tergite VIII divided by longitudinal suture basally (Fig. 5J), setose apically. Male sternite VIII strongly produced in middle of posterior edge, with long setae (Fig. 5E); female sternite VIII produced in middle of posterior edge, setose (Fig. 5H), anterior median strut short, narrowly elliptical. Male tergite IX completely divided into two parts, each with narrow basal projection (Fig. 5H). Male sternite IX narrow, strongly sclerotised at lateral edges, expanded before apex, with several sensilla trichoidea (Fig. 5G). Male tergite X divided into two parts, partly fused to tergite IX (Fig. 5H). Phallobase forming sheath around penis; tubular part short; anterior struts ca. 3.1× as long as tubular part; dorsal apodeme strongly sclerotised, lateral edges even (Fig. 5D). Parameres as in Figs 4G, H, 6B: left paramere longer than right one, EL/LPrL ratio: 7.09–8.59 (7.97 ± 0.41), dorsal process moderately dilated and obliquely truncate apically, with numerous sensilla trichoidea, ventral process shorter than dorsal one, slightly bent dorsad, narrowly rounded apically, median process short, produced ventrad, cluster of approximately nine sensilla campaniformia present above dorsal edge of median process (Figs 4I, 6B); left paramere with dorsal process subtruncate apically, with trichoid and campaniform sensilla, ventral process slightly shorter than dorsal one, bent dorsad, subtruncate at apex, EL/RPrL ratio: 9.67–12.08 (10.92 ± 0.58). Penis long, narrow, weakly expanded before apex (Fig. 5K). Ovipositor: proctiger moderately long, with sclerotised lateral baculi; paraprocts slightly shorter than gonocoxites, with sclerotised baculi; gonocoxites ventrally divided, setose, with oblique basal baculi; gonostyli attached subapically, each with two trichoid sensilla at apex.

Females are on average slightly larger than males. Males are more slender than females (Fig. 1). The second maxillary palpomere has longer setae in males than in females (Fig. 3A, B). Terminal maxillary palpomere is slightly narrower in females (Fig. 3A, B). The male protibia bears several elongate setae in proximal half (Fig. 4B), while the female protibia is uniformly setose. Male protarsomeres bear numerous thick setae oriented mesoventrad (Figs 4D, 5A). Protarsus and mesotarsus are more strongly dilated distally in females (Figs 4D, E, 5A, B).

Partial COI gene sequences of holotype and eight paratypes were submitted to GenBank (https://www.ncbi.nlm.nih.gov/genbank/). The accession numbers are listed in Table 1.

The specific epithet is derived from the Greek words πλατύς (platýs), meaning wide, broad, and πόδι (pódi) meaning foot. It refers to the expanded pro- and mesotarsi, an unusual condition that separates M.platypoda from morphologically similar congeners.

The species is known only from the island of Ischia in Italy.

Mordellistenaplatypoda was sampled in a series of 52 specimens on 29–30 June 2019. The sampling was carried out at two nearby localities (approximately 600 m apart) near Serrara village. The type locality (40.72138°N, 13.88305°E) was characterised by the steep rocky slopes with Mediterranean grassland communities (Fig. 7A, B). The specimens were collected by sweeping the inflorescences of Apiaceae spp. At the second location (40.71666°N, 13.88638°E), the specimens were collected from the inflorescences of Daucuscarota that grew in a ruderal community along the road (Fig. 7C, D). During the same collection events, the following Mordellidae species were also collected: Mediimordabipunctata (Germar, 1823), Mordellaaculeata Linnaeus, 1758, Mordellistenaepisternalis Mulsant, 1856, M.hirtipes Schilsky, 1895, M.minima A. Costa, 1854, M.pseudorhenana Ermisch, 1977, M.purpurascens A. Costa, 1854, M.wiebesi Batten, 1977, and Variimordabasalis (A. Costa, 1854).