Maechidius tarsalis Arrow 1941
Creators: name: Telnov, Dmitry
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Maechidius
Maechidius tarsalis

description: Maechidius tarsalis Arrow, 1941
Figs 90, 186, 259, 350, 422, 435, 437, 526, 565, 730–732
Type material
Lectotype (herewith designated)
PAPUA NEW GUINEA • ♂; “ Type [p, label circular, red frame] // SYNTYPE [p, label circular, blue frame] // ♂ [p]// PAPUA: Kokoda. 1,200ft. viii.1933. L.E.Cheesman. B.M.1933-577. [p] // Maechidius tarsalis, type Arrow [h]”; BMNH.
Paralectotype (herewith designated)
PAPUA NEW GUINEA • 1 ♂; “ SYNTYPE [p, label circular, blue frame] // ♂ [p] // PAPUA: Kokoda. 1,200ft. viii.1933. L.E.Cheesman. B.M.1933-577. [p]// Maechidius tarsalis, co-type Arrow [h]”; BMNH.
Arrow (1941: 454) based his description of M. aenescens on a number of specimens, although not explicitly stated, and gives a range of sizes. The lectotype is designated in order to enhance the stability of nomenclature and fix the specimen I based my redescription on, in case other (non-conspecific) syntypes are discovered in the future.
Description
Dorsum and venter uniformly brown, margins of labroclypeus and legs somewhat paler. Head flattened dorsally, shallowly impressed at either anterolateral angle of labroclypeus. Male labroclypeus (Fig. 186) broadly shallowly emarginate on anterior margin, its lateral margins strongly sinuous in both dorsal and lateral views. Anterolateral angles of labroclypeus obtuse, slightly protruding. Canthus broadly rounded in dorsal view. Head punctures irregularly hexagonal, horseshoe-shaped on frons and vertex, very deep and dense. Intervening spaces much smaller than punctures, glossy on forehead, in part microreticulate on frons. Head setae inconspicuous, suberect, slightly surpassing length of corresponding punctures. Pronotum strongly transverse, subopaque dorsally and laterally, with shallow circular dorsal impression on either lateral third. Anterior margin of pronotum slightly sinuous with anterolateral angles protruding. Basal margin of pronotum broadly rounded. Lateral margin of pronotum in dorsal view in anterior half nearly straight to slightly widened towards middle, strongly emarginate in prebasal third, strongly crenulate all along except in emargination area (Fig. 259); intervals between crenulae deep and rather large. Inconspicuous erect short seta present between every two crenulae. Lateral margin of pronotum arched in lateral view. Hypomeron separated from prosternum by moderately high nearly straight carina which is obtusely dentate medially, with long setae on anterolateral margin. Antennal pocket deep. Pronotal punctures irregularly hexagonal, very deep and dense, in part horseshoe-shaped. Intervening spaces much smaller than punctures, glossy to microreticulate. Pronotal setae inconspicuous, rise from anterior margin of each puncture; not or slightly surpassing length of corresponding puncture. Lateral and basal margins, antero- and posterolateral angles and hypomeron covered with microscopical velvety pubescence. Scutellar shield covered with microscopical velvety pubescence, narrowly rounded apically. Elytra slightly widened postmedially, opaque dorsally. Elytron with elevated and broadly interrupted tracks of four longitudinal carinae, including sutural one. Elytral punctures sinuous (elongate and narrow), incision-shaped, moderately deep and dense (Fig. 350). Intervening spaces densely microreticulate; reticulation somewhat less prominent on elevated parts, forming tracks of elytral carinae. Elytral setae inconspicuous, suberect; each seta rises from anterior margin of each incision, not or slightly surpassing its length. Stronger erect not much longer setae present in irregular longitudinal rows along remnants of carinae. Abdominal sternites medially each with bunch of erect golden setae (Fig. 435). Male pygidium flattened dorsally, with large dense shallow annular punctures (Fig. 526). Intervening spaces much smaller than punctures, densely microreticulate. Setae of pygidium sparse, suberect, surpassing length of corresponding punctures; each seta rises either from anterior margin or centre of corresponding puncture. Male protibia with three distal teeth on external margin, of which distal one prolonged and basal one inconspicuous and strongly obtuse (Fig. 422). Male basal metatarsomere leaf-like, flat and slightly convex dorsally, with brush of long dense setae on either lateroventral margin (Fig. 437). Spiculum gastrale as in Fig. 565. Aedeagus as in Figs 730–732.
Sexual dimorphism
Female is unknown.
description: Published as part of Telnov, Dmitry, 2020, 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, pp. 1-210 in European Journal of Taxonomy 721 on pages 119-121, DOI: 10.5852/ejt.2020.721.1127, http://zenodo.org/record/4122118