Maechidius penicilliger 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 : 456-458

Maechidius penicilliger Prokofiev , new species

Fig. 9

Type material. Holotype, male ( Fig. 9A ): D. N. Guinea / Bürgers S.G. ( ZMHB).

Description of the holotype. Total body length 7.5 mm, greatest width 4.2 mm. Dark reddish-brown, glossy; elytra slightly more reddish than the rest of body; antennae, palpi and tarsi reddish; setation pale. Antennae 9- segmented, club 3-lamellate, long (as long as funicle). Labroclypeus broadly concave anteriorly, its lateral margins strongly bisinuate in both dorsal and lateral views; anterolateral angles small and pointed, only slightly reflexed; canthus rounded, with strongly convex outer edge. Dorsal surface of head coarsely punctured, with deep annular or hexagonal punctures becoming more oblong posteriad; bottom of punctures with dense microscopical velvety pubescence; intervening spaces very narrow; setae (largely worn) very short, strongly adpressed, not surpassing diameter of corresponding puncture, except few longer semi-erect setae along inner margin of eye and anterior margin of labroclypeus. Underside of labroclypeus rather densely setose. Frons flat. Pronotum transverse, with anterior margin concave and slightly bisinuate; anterolateral angles strongly protruding, acute, surface of pronotum at their base weakly impressed. Pronotum widest at middle, with sides convex and smoothly converging anteriad and moderately deeply excavated in front of posterolateral angles; basal margin convex; posterolateral angles pronounced and somewhat attenuated, acute. Lateral margins of pronotum denticulate, with 9 broad-based tuberculate denticles before laterobasal excavation and about 5 smaller crenulations along the latter; a very short seta (often worn) present between every two tubercles. Pronotal punctures large and coarse, oval to elongate-oval but becoming annular or hexagonal close to lateral and anterior margins, with dense microscopical velvety pubescence; intervening spaces very narrow, ridge-like; setae minute, rising from anterior margin of puncture, shorter than corresponding puncture (setae largely worn and only few of them observable). Hypomeron separated from prosternum by high, sharp, slightly arcuate carina bearing moderately long setae; antennal pockets deep; punctures large, annular, with short adpressed setae not surpassing diameter of puncture; intervening spaces generally much smaller than diameter of punctures, distinctly microreticulate, matt. Scutellar shield apically pointed, with fine irregular puncturation; setae probably worn. Elytra weakly widened posteriad, subtruncate apically, with four longitudinal carinae (two between sutural joint and humeral umbo, one extending from humerus and disappearing in posterior half of elytron, and one passing along lateral margin to apical umbo) and elevated sutural margin. Punctures of elytral disc narrow, incisionshaped; intervening spaces generally smaller than length of punctures, microreticulate in part but generally glossy; setae adpressed, not or only slightly surpassing length of corresponding punctures. Pygidium flat, with large, annular, moderately shallow punctures; intervening spaces very narrow, distinctly microreticulate, matt; setae semi-erect, equal to slightly exceeding diameter of corresponding puncture. Thorax and abdominal ventrites with moderatelysized (smaller on abdomen) shallow annular punctures; intervening spaces narrow, distinctly microreticulate and matt; disc of metasternum impunctate and smooth along mid-line; setae semi-erect, those on thorax short, not or only slightly surpassing diameter of corresponding puncture, but somewhat longer on disc of metasternum; abdominal ventrites with mixed short and long setae arranged in transverse rows (setae becoming longer medially and on more posterior ventrites). Ventral profile of abdomen distinctly concave. First two abdominal ventrites with a slight protuberance at midline bearing somewhat stiffened setae (less expressed on second ventrite) ( Fig. 9B ). Protibia only slightly widened distally, with two longitudinal carinae dorsally and two apical teeth directed forward and laterally; basal tooth untraceable ( Fig. 9C ). Protibial spur present, straight. Metatibial spurs pointed, with lower spur curved and 1.5 times longer than upper one. Tarsomeres not elongated; underside of three basal metatarsomeres with a brush of long setae ( Fig. 9D ). Tarsal claws with pulvilli. Aedeagus and spiculum gastrale, as on Figs. 9E–H ; parameres symmetrical, with tips spatulate, regularly rounded ventrally; spiculum gastrale with shaft strongly bent.

Female unknown.

Differential diagnosis. The new species is very similar to M. brocki Telnov, 2020 , both externally and in aedeagus, differs mainly in the lateral margins of pronotum less excavate at base, in the presence of the long brushlike setae on male’s first three metatarsomeres (absent in M. brocki ) and in the shape of parameres having more symmetrically angulated tips less attenuated in the lateral view ( Figs. 9E–H ; Telnov 2020: figs. 601–603).

Etymology. The species is named from the Latin words “peniculus” (brush) and “gero” (to carry), due to the characteristic setation of the hind tarsomeres.

Remarks. Although not precisely stated on the label, this species was apparently collected on Huon Peninsula, as the other specimens from the Bürgers’ samplings housed in ZMHB.

Figures

FIGURE 9. Holotype of Maechidius penicilliger Prokofiev, new species. (A) dorsal view; (B) first three abdominal ventrites, ventral view (medial protuberances arrowed); (C) protibia; (D) hind tarsi, lateral view; (E) aedeagus, lateral view; (F) parameres, dorsal view; (G) spiculum gastrale, dorsal view; (H) ditto, lateral view. Scale bars: (A, C, D) 1.0 mm; (B, E–H) 0.5 mm.