Hoplia dubia Leo, 2017, new species
Creators: name: Leo, Piero
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Melolonthidae
Hoplia
Hoplia dubia

description: Hoplia dubia species group
The populations previously referred to Hoplia dubia are here split into three species, with the introduction of two new names, H. messapia new species and H. meridiana new species. The type series of Hoplia dubia is considered lost and a neotype is designated. The strong similarities between these three species warranted the recognition of a species group, which is described below. Each of the three species is then described using diagnostic characters not shared by all three species in the group.
Although Hoplia is not typically divided into species groups, we feel that recognizing a new species group is warranted here since these three species are extremely similar to each other, share the same ecology, and are easily distinguished from all other European Hoplia.
Description. Male. Size. Medium sized Hoplia: PBL: 5.7–7.6 mm; TBL: 7.1–9.2 mm; MBW: 3.4–4.9 mm.
Color. Head, pronotum, scutellum, propygidium, pygidium, and ventral surface piceous black. Elytra usually light brown to ferrous brown, more-or-less narrowly darkened along the basal margin and sometimes the suture; specimens with elytra completely dark brown or black are scattered among others at least in some populations. Antennal club piceous, funicle dark brown to piceous. Legs with femora piceous, tibiae dark brown to piceous, base and apex of claws chestnut brown.
Scales. Body with sparse scales both on dorsal and ventral surface, directed backwards, more-or-less inclined towards the midline at the sides of pronotum. Shape: narrowly lanceolate to drop-shaped, oval, elliptic, or rounded; on head, legs, and ventral side, on average, more slender than elsewhere; on pronotum, generally more slender along margins than on the disc. Color: variable, but ventral side and pygidium with color shifting towards the blue end of the spectrum in respect to the dorsal side. Dorsal side normally dull, with scales nacreous or shinier at least along the sides of the pronotum and the base of the elytra; specimens covered with shinier scales are scattered among ordinary ones in some populations.
Setae. Head bearing sparse setae, erect or slightly curved backwards on the frons, denser on epistomal canthi; the latter longer than those of the clypeus but shorter than those of the anterior area of pronotum. Pronotum bearing sparse, long, erect, hair-like setae, in lateral view their insertion roughly perpendicular to the integument except in the middle of the basal area, where they are more recumbent, curved backwards. Elytra bearing sparse setae, semierect, directed backwards, hair-like or bristle-like, shorter than pronotal setae and near the apical area shorter than on the rest of the elytra; epipleura with a fringe of short setae. Distal part of propygdium and pygidium with mostly recumbent setae, except along margins in the distal part of the pygidium, where they are erect. Ventral side, femora and tibiae set with long, erect setae, rather dense on hypomera of mesothorax, sparser but evenly distributed elsewhere.
Morphology. Head with integument shiny, with irregular transversal wrinkles. Clypeus trapezoidal, borders slightly raised, anterior border straight, anterior angles rounded, sides converging forwards and basally forming an angle with the epistomal canthi; frontoclypeal suture entire, straight, weakly impressed. Pronotum finely microsculptured and hence with dull appearance, subtrapezoidal, anterior angles subacute, sides feebly curved, either evenly convex or slightly angled, more-or-less sharply crenulate, usually more so in the basal half, posterior angles nearly right, broadly rounded, basal margin arcuate, regular, feebly sinuate near posterior angles. Scutellum subtriangular, with slightly curved sides, to semielliptical, variable within each species. Elytra poorly sculptured, almost shiny, bearing a shallow basal depression and with basal margin obliquely truncate. Maximum width near the mid-length, gently narrowing both anteriorly and posteriorly, with well-developed humeral calli and subapical umbones; sides feebly and evenly arcuate, steeply sloping at humeri. Propygidium and pygidium with integument shagreened and miscrosculptured, giving a dull appearance; pygidium flat or almost so. Antennae with 9 antennomeres (subgenus Hoplia). Outer margin of protibia bidentate, the third tooth absent, its position sometimes marked by a barely noticeable discontinuity of the margin. Tarsomeres 1–4 truncate, conical, ventral apical region progressively more protruding from tarsomere 1 to tarsomere 4, each crowned at apex with setae, spiniform on the ventral side, simple elsewhere. Both claws of protarsus and mesotarsus bifid, the outer claw less than half the length of the inner; claw of metathoracic legs not bifid, with a shallow medial furrow along the internal surface.
Female. Only the sexually dimorphic characters are described.
Color. Tarsi lighter, rusty orange to brown. Lighter color may apply to tibiae and femora also. Intraspecific variations for both tarsi and tibia/femora conditions are verified.
Morphology. Body stouter, more convex. Protibia slightly shorter and comparatively slightly broader. Posterior femora (slightly) and tibia (strongly) shorter, the latter much broader in lateral view. Tarsi of all legs shorter and slender, with considerable reduction of tarsomere 5 and of the claws, in particular on the prothoracic legs. The reduction of the claws concerns in particular the inner (major) claw, therefore the outer claw is comparatively longer, reaching or slightly exceeding half the length of the other. Pygidium either almost flat (as in males) or more convex and elongate, slightly impressed at the basal angles.
Included species. The group includes Hoplia (Hoplia) dubia (Rossi, 1792), H. (H.) meridiana new species, and H. (H.) messapia new species.
description: Published as part of Leo, Piero, 2017, On the taxonomy of the Italian endemic Hoplia dubia (Rossi, 1792), with the description of two new species (Coleoptera: Scarabaeidae: Melolonthinae), pp. 201-224 in Zootaxa 4320 (2) on pages 203-204, DOI: 10.11646/zootaxa.4320.2.1, http://zenodo.org/record/891714