Maechidius telnovi Prokofiev, 2022

Prokofiev, Artem M., 2022, New species and records of Maechidius Macleay, 1819 from New Guinea (Coleoptera: Scarabaeidae: Melolonthinae), Zootaxa 5205 (5), pp. 445-462 : 459-460

Maechidius telnovi Prokofiev , new species

Fig. 11

Type material. Holotype, male ( Fig. 11A–B ): “ New Guinea / Pratt ” ( BMNH).

Description of the holotype. Total body length 8.5 mm, greatest width 4.8 mm. Black, alutaceous; legs dark reddish-brown to blackish, with tarsi and forelegs more reddish than middle and hind tibiae and femora; antennae and palpi reddish-brown; setation pale. Antennae 9-segmented, club 3-lamellate, scapus strongly inflated at distal extremity. Labroclypeus broadly concave anteriorly, its lateral margins weakly sinuous in both dorsal and lateral views; anterolateral angles short and broad, moderately protruding, reflexed at distal margin only; canthus rounded. Punctures on dorsal surface of labroclypeus and frons annular, gradually increasing in size and density from anterior margin of labroclypeus toward frons, with dense microscopical velvety pubescence; intervening spaces very narrow, convex, very finely microreticulate. Frons slightly convex. Pronotum transverse, with anterior margin concave and only slightly bisinuate, and anterolateral angles strongly protruding, acute. Pronotum widest at middle, its sides weakly convex and smoothly converging anteriad before mid-length, weakly concave behind mid-length; basal margin regularly convex; posterolateral angles obtuse. Lateral margins of pronotum distinctly crenulate, with 24 crenulae better expressed in posterior two-thirds of lateral margin; a short seta present between every two crenulae. Pronotal punctures large and deep, ovate, with dense microscopical velvety pubescence; intervening spaces narrow, convex, glossy in part, forming an allusion of wavy longitudinal ridges. Hypomeron separated from prosternum by flange-like carina bearing long and sparse setae; antennal pockets very deep. Punctures of hypomeron moderately large and not densely distributed, annular, with setae not surpassing diameter of puncture; intervening spaces variable, matt, with very indistinct microsculpture. Scutellar shield apically rounded; puncturation similar to that on pronotum, but punctures smaller and intervening spaces less convex, matt. Elytra moderately widened posteriad, broadly rounded apically, with conspicuous apical declivity; apical umbones transversely extended, not callose. Base of elytra weakly impressed close to margin. Punctures of elytra round to ovate or slightly hexagonal, deep, with dense microscopical velvety pubescence, becoming smaller toward sutural joint and side-margins; intervening spaces very narrow, convex, forming an allusion of longitudinal carinae (two of them being most expressed on each elytron between scutellar shield and humeral umbo), very finely microreticulate, matt. Pygidium flat, with dense elongate-oval puncturation bearing dense microscopical velvety pubescence and short adpressed to semierect setae slightly or not surpassing length of punctures. Thorax rather densely punctured, with punctures round, moderately-sized (about twice smaller than those on elytral disc), bearing dense microscopical velvety pubescence and very short adpressed setae, slightly or not surpassing diameter of puncture; intervening spaces slightly variable but mainly smaller than diameter of punctures, somewhat convex and finely microreticulate. Abdomen concave in profile, with last two visible ventrites somewhat bulging ventrally ( Fig. 11B ); all ventrites lacking protuberances or patches of setae along their middle; puncturation similar to that on thorax but setae somewhat longer, especially on posteriormost visible ventrite. Protibia widened distally, bearing a pair of closely sitting submarginal longitudinal carinae; with two poorly developed apical teeth, basal tooth and protibial spur absent ( Fig. 11C ). Metatibial spurs straight and of equal size, their tips not acute. All tarsomeres short, ordinary. Tarsal claws with pulvilli. Aedeagus and spiculum gastrale, as on Figs. 11D–F ; parameres symmetrical, distinctly clavate at tips, with short unpaired ventral tooth at base; spiculum gastrale fan-shaped, with anterior margin weakly concave.

Female unknown.

Differential diagnosis. This new species appears to be most similar to M. muticus Arrow, 1941 ( Fig. 12 ). The aedeagi in both species are similar in bauplan; however, the new species can be distinguished by the more clavate tips of the parameres and distinctly toothed ventral collar at the base of the parameres (cf. Telnov 2020: figs. 673– 675). The shape of the spiculum gastrale is also distinctive (cf. Telnov 2020: fig. 555). Externally, the new species differs from M. muticus by larger punctures on pronotum and elytra, more convex intervening spaces bearing sparse setae, matt (vs. glossy) integument, less sharpened anterolateral angles of labroclypeus, weakly bisinuate anterior margin of pronotum (vs. strongly bisinuate, clearly convex at middle in M. muticus ), absence of protibial spur and abdomen strongly concave in profile (vs. almost straight).

Orientation of intervening spaces between pronotal punctures in the new species may allude a fingerprint-like pattern postulated for M. caperatus Telnov, 2020 and M. sturnus Arrow, 1941 , although the course of ridges is much less sinuous than in these species ( Telnov 2020: figs. 30, 87) and no fingerprint pattern is observed on elytra. Furthermore, both aforementioned species show no other resemblances with M. telnovi , new species in external features or genitalia.

Etymology. This species is dedicated to Dmitry Telnov (BMNH), who prepared the recent comprehensive treatment of this genus ( Telnov 2020).

Figures

FIGURE 11. Holotype of Maechidius telnovi Prokofiev, new species. (A) dorsal view; (B) lateral view; (C) protibia; (D) aedeagus, lateral view; (E) parameres, dorsal view; (F) spiculum gastrale, dorsal view. Scale bars: (A–C) 1.0 mm; (D–F) 0.5 mm.

FIGURE 12. Male syntype of Maechidius muticus Arrow, 1941. (A) dorsal view; (B) lateral view; (C) protibia. Not in scale.