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 humeralis Heller, 1914 Figs 45 , 127–128 , 218 , 269 , 308 , 382, 475–476, 546, 623–625 Type material Lectotype [herewith designated] PAPUA NEW GUINEA • ♂ ; “Kais.Wilhelmsland Toricelli [sic ♂ ] Gebirge Dr.Schlaginhaufen [p, blue label]// 1910 [p] 1 [h] [blue label]// Typus ! [p] humeralis H. [h, red label]// Staatl. Museum für Tierkunde. Dresden [p]”; SNSD . Paralectotypes PAPUA NEW GUINEA • 1 ♀ ; “ Kais.Wilhelmsland Toricelli [sic ♂ ] Gebirge Dr.Schlaginhaufen [p, blue label]// 1910 [p] 1 [h] [blue label]// Staatl. Museum für Tierkunde.Dresden [p]”; SNSD • 1 ♀ ; “ Kais. Wilhelmsland Paup Dr.Schlaginhaufen [p, blue label]// 1910 [p] 1 [h] [blue label] // Typus ♂ [p] humeralis H. [h, red label]// Staatl. Museum für Tierkunde.Dresden [p]”; SNSD . Remarks Heller (1914: 628) based his description of M. humeralis on a number of specimens, although not explicitly stated, and two different localities are given. The lectotype designated here is one of two syntypes with Heller’s original “typus” handwriting on a red label and is the single male syntype . Lectotype designation is made in order to enhance the stability of nomenclature and fix the only male specimen I based my redescription on, in case other syntypes are discovered in the future. Description MEASUREMENTS. Total body length 6.80 (smallest paralectotype ) to 8.10 ( lectotype ) mm. Dorsum and venter uniformly black-brown except for brown appendages and labroclypeus. Head flattened dorsally, glossy dorsally and ventrally. Male labroclypeus ( Fig. 127 ) broadly and moderately deeply emarginate anteriorly, its lateral margins strongly sinuous in both dorsal and lateral views. Anterolateral angles rounded, moderately strongly protruding, raised up at angle of nearly 80-90° to frons in lateral view. Anterior and lateral margins of labroclypeus smooth. Female labroclypeus as in Fig. 128 . Underside of labroclypeus with sparse moderately long setae along anterior and lateral margins. Canthus broadly rounded in dorsal view. Punctures of frons irregularly shaped, annular, large and shallow. Intervening spaces subopaque, variably large. Setae inconspicuous, suberect, sparse, generally hardly surpassing length of corresponding punctures. Antenna 9-segmented, club 3-lamellate. Pronotum transverse, flattened dorsally, glossy dorsally and laterally. Anterior margin of pronotum slightly sinuous with protruding anterolateral angles, basal margin slightly sinuous. Lateral margin of pronotum sinuous in dorsal and lateral view, delicately crenulate all along ( Fig. 218 ). Long erect seta present between every two crenulae. Hypomeron separated from prosternum by moderately high emarginate carina, with moderately long setae on its anterolateral margin ( Fig. 269 ) opposite to compound eye. Antennal pocket moderately deep. Punctures of pronotal disc large, variably shaped (generally ovoid), double annular, moderately deep; lateral and latero-basal punctures irregularly ovoid, oblong, larger than median ones. Intervening spaces generally smaller than punctures, glossy. Setation slightly longer than on head, appressed to suberect; seta rises from anterior margin of each puncture, not or hardly surpassing its length. Scutellar shield pointed apically. Elytron subopaque, with very vague tracks of two longitudinal carinae. Sutural carinae not present. Punctures of elytral disc sinuous, long and narrow, incisionshaped, dense ( Fig. 308 ). Intervening spaces wrinkled, opaque while densely transverse microstriate, generally larger than incision-shaped punctures. Intervening spaces delicately microreticulate. Setae inconspicuous, suberect, not surpassing length of punctures. Pygidium in both sexes ( Figs 475–476 ) flattened dorsally, with very large and shallow irregularly shaped annular punctures. Intervening spaces microreticulate, distinctly smaller than punctures. Setae of pygidium moderately long, suberect. Protibia widened distally, dorsally with delicate longitudinal carina, in both sexes with three external teeth: acute largest distal, less acute predistal and strongly obtuse small median (Fig. 382). Male and female protibial terminal spur thin and long. Male metatibial terminal spurs long, nearly equally long, female lower metatibia spur distinctly longer than upper. Tarsal claws with pulvilli. Spiculum gastrale as in Fig. 546 . Aedeagus as in Figs 623–625 . Sexual dimorphism Lamellae of antennal club longer in male, labroclypeus stronger emarginate in female (in dorsal view) than in male.