A revision of the Maechidiini Burmeister, 1855 (Coleoptera: Scarabaeidae: Melolonthinae) from the Indo-Australian transition zone, and the first record of the tribe west of Wallace’s Line Author Telnov, Dmitry text European Journal of Taxonomy 2020 2020-10-19 721 1 210 journal article 9693 10.5852/ejt.2020.721.1127 0cd61b23-1089-4c1b-bfc0-487887abad84 4122118 89E62EF8-2E45-4C59-94B7-6A5603E8939B Maechidius nanus Arrow, 1941 Figs 64 , 151 , 236 , 327 , 400, 496, 676–678 Type material Syntypes INDONESIA • 1 ♂ ; “ Type [p, label circular, red frame] // Syntype [p, label circular, blue frame] // N. DUTCH NEW GUINEA : Waigeu. Camp Nok. 2,500ft. iv.1938 . L.E.Cheesman. B.M.1938-593. [p] // Maechidius nanus Arrow Co-type [h]”; BMNH • 20 syntypes ; “ Syntype [p, label circular, blue frame] // N. DUTCH NEW GUINEA : Waigeu. Camp Nok. 2,500ft. iv.1938 . L.E.Cheesman. B.M.1938- 593. [p]”; BMNH • 152 syntypes ; “N. DUTCH NEW GUINEA : Waigeu. Camp Nok. 2,500ft. iv.1938 . L.E.Cheesman. B.M.1938-593. [p]”; BMNH • 1 ♂ ; “ ♂ [p] // N. DUTCH NEW GUINEA : Waigeu. Camp Nok. 2,500ft. iv.1938 . L.E.Cheesman. B.M.1938-593. [p] // Maechidius nanus Arrow Co-Type [h]”; BMNH . Remarks There are several male syntypes from the same locality available for this species. A lectotype is therefore not designated since there is no risk of confusion. Redescription Male labroclypeus ( Fig. 151 ) broadly V-shaped emarginate on anterior margin, its lateral margins sinuous in both dorsal and lateral views. Head dorsal punctures circular, variably large, shallow, annular, with shagreened background. A long suberect seta rises from anterior margin of each puncture. Intervening spaces glossy, larger on labroclypeus, generally much narrower than punctures on frons. Pronotum broadly emarginate on anterior margin, anterolateral angles slightly protruding, basal margin broadly rounded. Lateral margin of pronotum broadly rounded in dorsal view, with large crenulae all along ( Fig. 236 ). A moderately long suberect seta present between every two crenulae. Lateral margin of pronotum nearly straight in lateral view. Hypomeron separated from prosternum by low nearly straight carina, with moderately long setae on its anterolateral margin opposite to compound eye. Antennal pocket shallow. Pronotal punctures circular, annular, large, shallow. Intervening spaces glossy, variably large. Minute appressed seta rises from anterior margin of each puncture, not surpassing midlength of corresponding puncture. Elytral punctures irregularly ovoid, annular, shallow, arranged in double longitudinal rows ( Fig. 327 ). Intervening spaces glossy, generally larger than punctures. Elytral setae minute, surface looks glabrous under 50 × magnification; minute seta rises from anterior margin of each puncture, not surpassing midlength of corresponding puncture. Pygidium in both sexes flattened dorsally, with large circular to ovoid shallow annular punctures ( Fig. 496 ). Intervening spaces generally smaller than punctures, glossy. Setae inconspicuous and short in anterior part, becoming longer than corresponding punctures in distal part. Protibia in both sexes widened distally, with three distal teeth on external margin, of which two distal ones larger and stronger acute (Fig. 400). Protibia without terminal spur in both sexes. Male aedeagus as in Figs 676–678 . Sexual dimorphism Lamellae of female antennal club shorter.