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

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Scydmaenus (Corbulifer) monstrosetibialis

sp. n.

Scydmaenus (Corbulifer) monstrosetibialis   sp. n.

( Figs 24–26 View FIGURES 24–26 , 56 View FIGURES 55–65 , 70 View FIGURE 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 View FIGURES 24–26 ) 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 View FIGURES 55–65 ) 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 View FIGURES 24–26 ) 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 View FIGURE 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.


Australian National Insect Collection