Scydmaenus (Corbulifer) monstrosetibialis, Jałoszyński, 2018

Jałoszyński, Paweł, 2018, ' Monster Scydmaenus' of Australia: revision of subgenus Corbulifer Franz (Coleoptera: Staphylinidae: Scydmaeninae), Zootaxa 4472 (3), pp. 505-531 : 513-515

Scydmaenus (Corbulifer) monstrosetibialis sp. n.

( Figs 24–26 , 56 , 70 )

Type material. HOLOTYPE: ( AUSTRALIA, QUEENSLAND): ♂, two labels: " AUSTRALIA: QLD / Lamington N.P. / Binna Burra / 900m, 23 Jun. 78 / S. & J. Peck" [white, printed], "rotted bark / and litter" [white, printed] ( ANIC). PARATYPES (36 exx.): QUEENSLAND: 27 ♂♂, 9 ♀♀, " AUST:QLD:SE / SpringbrookRepeater / 14 March 1997 / Monteith & Russell" [white, printed], "QM Berlesate 923 / 28°15'Sx 153°16'E / Rainforest, 1000m / Stick brushing" [white, printed] (QM, cPJ).

Diagnosis. Male metatibia with extremely large glandular broadening occupying ~ 3/4 of tibial length, much broader than metafemur, mesal tibial margin sinuate, lateral (external) tibial margin nearly straight in proximal fourth and strongly convex in distal 3/4; aedeagus in dorsal view broadest near base, with indistinctly delimited elongate apical portion, apical projections long and strongly bent dorsoproximad.

Description. Body of male ( Fig. 24 ) strongly convex, reddish brown, covered with setae slightly lighter than cuticle; BL 1.75–1.88 mm (mean 1.83 mm).

Head broadest at very small eyes, HL 0.35–0.38 mm (mean 0.37 mm), HW 0.38–0.43 mm (mean 0.41 mm); tempora in lateral view as long as 6 × length of eye, slightly convergent posterad and posteriorly bent mesad at a slightly obtuse angle. Punctures on frons and vertex very fine and shallow, inconspicuous; setae short, sparse and suberect. Antennae slender, AnL 0.93–1.00 mm (mean 0.95 mm), antennomeres I–VI each distinctly elongate, VII–X each distinctly transverse, IX–X much larger than VIII, XI variable in length, distinctly shorter than or subequal to IX–X combined, 1.7–2 × as long as broad.

Pronotum rounded, broadest slightly behind anterior third; PL 0.48–0.53 mm (mean 0.50 mm), PW 0.45–0.50 mm (mean 0.47 mm). Antebasal pits indistinct. Punctures on pronotal disc very fine and shallow, inconspicuous; setae short, sparse and suberect.

Elytra oval, broadest in front of middle; EL 0.93–1.00 mm (mean 0.96 mm), EW 0.68–0.78 mm (mean 0.72 mm), EI 1.29–1.46; apices separately rounded. Punctures relatively large and dense but very shallow; setae longer and denser than those on pronotum, suberect to erect.

Metatibia ( Fig. 56 ) in dorsal view with slender proximal 1/4; distal 3/4 extremely and abruptly broadened, convex dorsally, with a narrow dorsal 'pocket' whose mesal edge bears a group of dense setae.

Aedeagus ( Figs 25–26 ) moderately slender; AeL 0.40 mm; in dorsal view median lobe broadest near basal third, indistinctly narrowing up to subapical region, which is narrowed more rapidly, demarcating short subtrapezoidal apical portion; apical projections long and slender, bent dorsoproximad at a sharp angle.

Female. Similar to male, with unmodified metatibiae but with eyes about as large as those in male. BL 1.80– 1.90 mm (mean 1.85 mm); HL 0.38 mm, HW 0.40–0.41 mm (mean 0.40 mm), AnL 0.90–0.95 mm (mean 0.92 mm); PL 0.48–0.50 mm (mean 0.50 mm), PW 0.45–0.50 mm (mean 0.46 mm); EL 0.93–1.03 mm (mean 0.98 mm), EW 0.73–0.78 mm (mean 0.74 mm), EI 1.28–1.32.

Distribution. Queensland; central-eastern coast of Australia ( Fig. 70 ).

Etymology. The name monstrosetibialis refers to the unusually enlarged male metatibiae.

Remarks. Males of this species have the largest and most bizarre modifications of metatibiae; the broadening occupies 3/4 of tibial length and in dorsal view is over twice as broad as the metafemur. Scydmaenus monstrosetibialis is most similar to S. tamborinensis , but it can be easily distinguished on the basis of a larger metatibial modification, strongly elongate and pointed projections of the aedeagal apex, and a different silhouette

of the median lobe in dorsal view. Moreover, males of S. monstrosetibialis have the eyes as small as females of S. tamborinensis , males of the latter having much larger eyes.

Figures

FIGURE 70. Distribution of Corbulifer species.

FIGURES 24–26. Scydmaenus (Corbulifer) monstrosetibialis sp. n. Habitus of male (24), aedeagus in dorsal (25) and lateral (26) views.

FIGURES 55–65. Male metatibia in dorsal view. Scydmaenus tamborinensis Franz (55), S. monstrosetibialis sp. n. (56), S. bellenderanus sp. n. (57), S. pseudorobustus Franz (58), S. kiwarrakianus sp. n. (59), S. gushi sp. n. (60), S. gibraltar sp. n. (61), S. eungellanus sp. n., specimen from Mount William (62) and from Peases Lookout (63), S. fishermontanus sp. n. (64), S. super sp. n. (65).