Maechidius sabatinellii Telnov, 2025

Telnov, Dmitry, 2025, New and poorly known Papuan species of Maechidius W. S. MacLeay, 1819 (Coleoptera: Scarabaeidae: Melolonthinae: Maechidiini), Zootaxa 5665 (1), pp. 58-66 : 62-65

Maechidius sabatinellii Telnov , sp. nov.

http://zoobank.org/ 62E6CA1D-AF3C-4543-9A25-3C4088C4079E

( Figures 3–4 )

Type material. Holotype ♂ ( MHNG): X II 79 [handwritten] PNG / Morobe Umg. Gurakor [printed].

Measurements. Holotype ♂: total body length 8.7 mm; head 1.3 mm long, across canthus 1.9 mm wide; pronotum 2.0 mm long, maximum width 3.1 mm; elytral length 5.4 mm, maximum width of elytra 3.6 mm.

Description of the holotype ♂. Body uniformly rufous, legs and antennae slightly paler. Maximum head width is across canthus. Male labroclypeus ( Fig. 3A ) broadly, moderately V-shapely emarginate at anterior margin, its anterolateral angles rounded, strongly produced anteriorly. Lateral margins of labroclypeus sinuous in both dorsal and lateral view. Anterior angles of labroclypeus in lateral view strongly deflected - bent up at nearly 80° angle regarding plane of frons. Anterior and lateral margins of labroclypeus smooth, with some long setae dorsally and ventrally. Canthus broadly rounded in dorsal, slightly sinuous in lateral view. Compound eye large, divided by canthus to less than half-length. Head dorsal punctures circular to elliptical, moderately dense and deep. Intervening spaces moderately glossy, variably large but generally wider than puncture diameters. Head dorsal setae yellowishrufous, elongate-thickened, suberect, rather long; seta raises from each puncture, much longer than puncture diameter. Three to four extraordinary long erect setae positioned along inner eye margin and several – on canthus. Antenna 9-segmented, club 3-lamellate. Pronotum moderately glossy dorsally and laterally. Anterior margin of pronotum medially subtruncate, anterolateral angles slightly produced anteriorly, basal margin barely sinuous. Lateral margin of pronotum in dorsal view nearly straight (diverging) in anterior half, rounded medially, roundedstraight constricted towards base, nearly entire to barely lobulate ( Fig. 3B ); lobulae more obvious in posterior third of lateral margin. Extraordinary long (the length of compound eye or longer), erect curved setae present on lateral pronotal margin at places where there would be an interlobular space in other members of the genus. Lateral margin of pronotum slightly arched in lateral view. Pronotal punctures circular to subcircular, moderately large, moderately dense, subannular, rather shallow. Intervening spaces moderately glossy and smooth, twice as wide as to slightly narrower than puncture diameters. Setae on pronotal disc similar as those on frons. Hypomeron separated from prosternum by low nearly straight carina, with long setae on its anterolateral extent opposite of compound eye. Antennal pocket shallow. Median anterior process of proventrite long brushy setose, short, strongly produced anteroventrally. Scutellar shield broadly triangular, rounded apically, moderately glossy and irregularly punctured. Elytra subrectangular, slightly widened in posterior two thirds, moderately glossy, each elytron with inconspicuous tracks of two glabrous slightly elevated longitudinal costae. Elytral apical area not humped. Punctures of elytral disc elliptical, annular, moderately deep and dense. Intervening spaces moderately glossy, smooth, in part elevated in part flattened, much wider than puncture diameters. Elytral setae yellowish, variably long, sparse, thickened (subclavate), subdecumbent, distinctly longer on lateral sides of elytron than on disc. Lateral edge of elytron with row of long erect setae. Male pygidium with moderate and shallow annular punctures and dense moderate to long subclavate setae; its posterior margin with dense extraordinary long setae ( Fig. 3A ). Male protibia with apically rounded teeth, one distal and one predistal ( Fig. 3A ). Male terminal protibial spur short, straight, pointed apically. Male upper mesotibial terminal spur approximately twice as long as lower spur, thicker; both spurs apically pointed. Male metatibial terminal spurs subequal; upper spur comparatively more slender and slightly sinuous, apically nearly pointed; lower spur slightly curved, apically rounded. All male tarsi longer than corresponding tibiae. Aedeagus as in Fig. 4 .

Sexual dimorphism. Female is unknown.

Derivatio nominis. Named for Guido Sabatinelli (MHNG), a well-known specialist on Melolonthinae (Scarabaeidae) and a responsive colleague. Masculine genitive singular.

Differential diagnosis. This new species is similar to several Papuan congeners. Only two species of similar appearance have the lateral pronotal margin extraordinarily long setose: M. esau Heller, 1914 (northern and eastern New Guinea) and M. rugicollis Moser, 1920 (eastern and northern New Guinea). Maechidius esau differs from M. sabatinellii sp. nov. in the distinctly lobulate lateral pronotal margin, the dorsal setae not thickened, the considerably shorter lateral pronotal and elytral setae, the more regularly circular pronotal dorsal punctures. In M. rugicollis , the pronotal disc with irregularly shaped, glossy median calluses, the dorsal setae are whitish and contrastingly paler than the brown dorsum and the pygidium with weak metallic reflection. The new species differs from M. lobaticeps Frey, 1969 (most of New Guinea including Cenderawasih Bay), another similar species, in the lack of the metallic reflection on the dorsum, the comparatively shallower emarginate anterior margin of labroclypeus, the considerably longer lateral pronotal setae, the presence of the long setae on the elytral lateral edge. Finally, the new species differs from M. riedeli Telnov, 2020 (Yapen Island, Cenderawasih Bay Islands) in the comparatively shallower impressed anterior margin of labroclypeus, the deeper elytral punctures, the laterally extraordinarily long setose pronotum, the strongly transverse pronotum and the not contrastingly paler dorsal setae.

Distribution. Lae surroundings, Morobe Province, eastern Papua New Guinea.

Figures

FIGURE 3. Maechidius sabatinellii Telnov, sp. nov. holotype ♂, dorsal view. A, habitus; B, anterior portion of the right lateral margin of pronotum (a lobule and traces of interlobular spaces are shown by black lines); C, pygidium [not to scale].

FIGURE 4. Maechidius sabatinellii Telnov sp. nov. holotype ♂, aedeagus.A, dorsal view; B, ventral view; C, lateral view [not to scale].