Malaisdius, Brunke, 2023

Brunke, Adam James, 2023, Review of Quedius (Coleoptera, Staphylinidae) described from the 1934 expedition by R. Malaise to Myanmar, European Journal of Taxonomy 864, pp. 117-145 : 126-127

Genus Malaisdius gen. nov.

urn:lsid:zoobank.org:act:6947E75F-7462-4642-A8D4-2AA3EA25E22C

Figs 2A–B , 4E–F , 5A–B , 6A–G , 7D

Type species

Quedius ruficeps Scheerpeltz, 1965 .

Diagnosis

Within the Microsaurus lineage, Malaisdius gen. nov. can be recognized by the following: elytral disc distinctive, uneven and with deeply impressed, foveate and setose punctures ( Fig. 4F ); abdominal tergites III–VI with distinct, coarsely punctate basal impressions, disc otherwise impunctate or nearly so, punctures elongate ( Fig. 5A–B ). In the latter two features, species of Malaisdius gen. nov. superficially resemble some members of cyrtoquediine genus Bolitogyrus Chevrolat, 1842 though asetose punctures are always present in Bolitogyrus and the forebody is entirely without microsculpture.

Etymology

This genus is dedicated to the Swedish explorer and entomologist René Malaise, who collected a diversity of rove beetles at Kambaiti Pass, Kachin, Myanmar. Malaise is also famous for the invention of the insect trap that bears his name, which has revolutionized our knowledge of insect biodiversity and was first used on a significant scale in Kambaiti ( Sjöberg 2014).

Description

Medium-sized, glossy beetles, with bright coloration. With the character states of Quediini (sensu Brunke et al. 2021) and the following: antennomere 3 longer than 2, without dense setation or tomentose pubescence; outer antennomeres (6–10 or 8–10) weakly transverse and slightly asymmetrical; antennae inserted far from eyes, about 2.0 × the width of antennal sclerite; head with eyes large, strongly convex, protruding from lateral head margin, temples distinct, about half the length of eyes; eyes subparallel, inner margin forming acute angle with supra-antennal ridge; basal puncture doubled, interocular punctures absent, genal puncture present but extremely small, rudimentary; frons not well developed anterolaterad of antennal insertions; labrum notched medially creating two lobes; apical maxillary and labial palpomeres fusiform and glabrous; infraorbital ridge complete to base of mandibles; gular sutures convergent towards neck, narrowly spaced posteriad; mandibles with small dorsolateral groove; right mandible with two teeth, distal tooth on lower plane compared to proximal; pronotum shield-shaped, slightly explanate; marginal punctures touching marginal bead, dorsal rows with three punctures, sublateral rows with only one puncture, therefore not extended posteriad of large lateral puncture (two female specimens with puncture-like elements (without sockets) giving superficial appearance of 2–3 punctures in the sublateral row), with single large lateral puncture; hypomeron strongly inflexed, hypomeron not visible; basisternum with pair of small, pale macrosetae, with well-developed longitudinal carina; scutellum impunctate; elytron with subbasal ridge complete, forming scutellar collar; row of humeral spines present but short (2–4 spines); disc of elytra without microsculpture between the punctures, surface uneven, punctures irregularly and sparsely distributed, or in very loose rows, punctures bearing setae and situated in broad depressions; foretibia without lateral spines but with apical spur; metatibia with only two slender spines on lateral face; metatarsomeres with disc setose; prototergal glands likely absent, with only vague, shallow impression lacking marginal setae; abdominal tergites III–VI with distinct basal depressions bearing elongate punctures, remainder of disc impunctate or nearly so; abdominal sternite III transverse basal line acutely and sharply produced posteriad at middle; males without modifications on sternite VII; aedeagus asymmetrical in known species, with well-developed paramere, paramere without peg setae; aedeagus without large copulatory sclerites in internal sac.

Distribution

Malaisdius gen. nov. is known from the Himalaya of Nepal and the mountains of northern Myanmar.

Bionomics

Nothing is currently known about the natural history of Malaisdius gen. nov.

Remarks

According to phylogenomic analyses ( Brunke et al. 2021), the sister group of Malaisdius gen. nov. is the more generalized Masasatoi group (see below), currently included within polyphyletic Quedius (Microsaurus) but will be treated as a separate genus in a future study.

Key to the species of Malaisdius gen. nov.

1. Body bicolored, head and pronotum orange-red, sharply contrasting with elytra and abdomen ( Fig. 2A ); legs entirely pale ( Fig. 2A ); elytral punctures irregularly placed; paramere in basal half subequal in width to median lobe, apex not hooked ( Fig. 6A ); Myanmar......................................... ........................................................................................ M. ruficeps ( Scheerpeltz, 1965) comb. nov.

– Body more evenly colored, yellow-orange, with darker areas on the elytra ( Fig. 2B ); hind femur with apical dark band ( Fig. 2B ); elytral punctures in loose rows ( Fig. 4F ); paramere in basal half distinctly narrower than median lobe, apex hooked ( Fig. 6F ); Nepal................................................ ................................................................................................................ M. smetanai gen. et sp. nov.

Figures

Fig. 2. A–E. Dorsal habitus. A. Malaisdius ruficeps (Scheerpeltz, 1965), ♂, paratype (NHW). B. Malaisdius smetanai gen. et. sp. nov., ♂, holotype (NME). C. Quedius (Microsaurus) rutilipennis Scheerpeltz, 1965, ♂, holotype (NHRS). D. Q. (M.) piceolineatus Scheerpeltz, 1965, ♂ holotype (NHRS). E. Q. (M.) impressithorax Scheerpeltz, 1965, ♀ holotype (NHRS). F. Forebody of Q. (M.) impressithorax Scheerpeltz, 1965. Abbreviation: Pf = posterior frontal puncture. Scale bars = 1 mm.

Fig. 4. A–B. Indoquedius dispersepunctatus(Scheerpeltz, 1965). A. Elytra. B. Dorsal abdomen. C–D. I. recticollis (Scheerpeltz, 1965). C. Elytra. D. Dorsal abdomen. E–F. Malaisdius smetanai gen. et sp. nov. E. Head. F. Elytra. Abbreviations: Af = anterior frontal puncture; b = basal puncture; pf = posterior frontal puncture; sa = supraantennal puncture. Scale bars = 1 mm.

Fig. 5. A. Malaisdius ruficeps (Scheerpeltz, 1965), dorsal abdomen. B. M. smetanai gen. et sp. nov., dorsal abdomen. C–E. Quedius (Microsaurus) rutilipennis Scheerpeltz, 1965. C. Antenna. D. Pronotum (white arrow: marginal punctures removed from marginal bead; black arrow: anterior angles with marginal bead entirely visible in dorsal view). E. Elytra and basal abdomen. F. Q. (M.) masasatoi Smetana, 2007, pronotum (arrows indicating punctures of the dorsal row). Abbreviation: Pf = posterior frontal puncture. Scale bars: A–B, D–E = 1 mm; C, F = 0.5 mm.

Fig. 6. A, F, H–I, K–L.Aedeagus, in situ. A, F, H, K. Ventral view (inset showing paired teeth). I, L. Lateral view. B–D. Median lobe. B. Ventral view. C–D. Lateral view. E, G, J, M. Underside of paramere. A–E. Malaisdius ruficeps (Scheerpeltz, 1965). F–G. M. smetanai gen. et sp. nov. H–J. Quedius (Microsaurus) piceolineatus Scheerpeltz, 1965. K–M. Q. (M.) masasatoi Smetana, 2007. Scale bars: A–D, F, H–I, K–L = 0.5 mm; E, G, J, M = 0.1 mm.

Fig. 7. Female tergite X. A. Indoquedius dispersepunctatus (Scheerpeltz, 1965). B. I. parallelicollis (Scheerpeltz, 1965). C. I. recticollis (Scheerpeltz, 1965). D. Malaisdius ruficeps (Scheerpeltz, 1965). E. Quedius (Microsaurus) rutilipennis Scheerpeltz, 1965. F. Q. (M.) impressithorax Scheerpeltz, 1965. Scale bars = 0.1 mm.