Microscydmus (Scydmomicrus) nasicornis Franz

Jałoszyński, Paweł, 2014, The smallest Cyrtoscydmini of Australia: revision of Microscydmus Saulcy & Croissandeau and Penicillidmus gen. n. (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 3774 (1), pp. 1-30 : 19-20

Microscydmus (Scydmomicrus) nasicornis Franz

( Figs. 21 , 30 , 62 )

Microscydmus nasicornis Franz, 1975: 272 .

Material studied. Holotype: ♀: four labels: "Umg. Maipoton [sic!] / Queensld., Austr. / lg. H. Franz 1970 " and "Pa 77" on the reverse side [white, printed, reverse handwritten in blue ink], " Microscydmus / nasicornis / m. / det. H. Franz" [white, handwritten and printed], " Typus " [red, handwritten], " SAMA Database / No. 25-037026" ( SAM).

Revised diagnosis. Female: body uniformly light brown; frons subtriangular; punctures on head inconspicuous, only slightly more distinct than those on pronotum; BL> 0.60 mm; pronotum 1.4x broader than head, with ante-basal transverse groove; EI 1.556. Males and their diagnostic characters unknown.

Redescription. Body of female ( Fig. 21 ) moderately convex, elongate and slender, with moderately long appendages, BL 0.625 mm; cuticle glossy; body uniformly light brown with slightly lighter legs and palps; vestiture yellowish.

Head subtrapezoidal, broadest at eyes, HL 0.100 mm, HW 0.125 mm; tempora shorter than eyes, relatively weakly convergent caudad; vertex weakly convex; frons subtriangular, with distinct antero-median projection. Eyes moderately large and moderately projecting laterally from the head silhouette, finely faceted. Punctures on head dorsum fine and sparse, inconspicuous; setae short, sparse and suberect. Antennae slender, AnL 0.250 mm; antennomeres I–II elongate, III–X transverse; XI as long as broad.

Pronotum in dorsal view oval, broadest near anterior fourth, PL 0.175 mm, PW 0.175 mm; anterior and lateral margins rounded; posterior margin shallowly bisinuate; base of pronotum with two pairs of small and shallow pits, internal pair connected by transverse impression. Punctures on pronotal disc fine and inconspicuous; setae sparse, thin, short and suberect.

Elytra oval, slightly more convex than pronotum, broadest slightly anterior to middle, EL 0.350 mm, EW 0.225 mm, EI 1.556; basal impressions short; elytral apices separately rounded. Punctures on elytral disc as fine as those on pronotum; setae short, sparse and suberect. Hind wings well developed, about twice as long as elytra.

Legs moderately long and slender, without modifications.

Male. Unknown.

Distribution ( Fig. 62 b). E Australia (S Queensland).

Remarks. The only known female of Microscydmus nasicornis is most similar to the female of M. australiensis (distinguishing characters are discussed in the Remarks section under description of the latter species). Microscydmus nasicornis differs from other Australian congeners in the following characters:

- from M. capitiseboraci sp. n., M. queenslandicus sp. n. and M. styxianus sp. n. in the frons covered with inconspicuous punctures and more distinctly narrowing anteriorly; in these three species punctures on the head dorsum are distinct and the frons is shorter and less narrowed ( M. capitiseboraci ), broadly rounded ( M. queenslandicus ) or more subtrapezoidal than subtriangular ( M. styxianus ); additionally M. nasicornis is distinctly larger than M. capitiseboraci and M. queenslandicus (BL 0.625 mm vs. 0.512 mm and 0.500 mm, respectively), its pronotum is as long as broad (slightly broader than long in M. capitiseboraci ); its elytral index is low (EI 1.556 vs. 1.710 in M. capitiseboraci ); and the ratio EL/PL in M. nasicornis is clearly lower (2.000 vs. 2.400 in M. capitiseboraci and in M. queenslandicus , 2.540 in M. styxianus );

- from M. edithensis sp. n. in the uniformly yellowish-brown body pigmentation ( M. edithensis has the head distinctly darker than the pronotum and elytra); elytral sculpture (fine, inconspicuous punctures in M. nasicornis vs. dense and fine punctures forming fine transverse wrinkles in M. edithensis ); and distinctly lower ratio EL/PL (2.000 vs. 2.308);

- from M. tooloomensis in the presence of the transverse ante-basal impression on the pronotum (absent in M. tooloomensis ).

The locality indicated on the label as "Maipoton" (in the same form spelled in Franz (1975)) is most likely Mapleton near Nambour in South Queensland (according to Tom Weir and Adam Ślipiński; email to the author dated 10 Dec. 2013).

Figures

FIGURES 20 – 28. Dorsal habitus of holotypes. Microscydmus (Scydmomicrus) australiensis Franz, female (20); M. (Sc.) nasicornis Franz, female (21); M. (Sc.) capitiseboraci sp. n., male (22); M. (Sc.) queenslandicus sp. n., male (23); M. (Sc.) styxianus sp. n., male (24); M. (Sc.) edithensis sp. n., male (25); M. (Sc.) tooloomensis sp. n., male (26); Penicillidmus masseyensis sp. n., male (27); P. unicolor sp. n., male (28).

FIGURES 29 – 37. Body silhouette of holotypes. Microscydmus (Scydmomicrus) australiensis Franz, female (29); M. (Sc.) nasicornis Franz, female (30); M. (Sc.) capitiseboraci sp. n., male (31); M. (Sc.) queenslandicus sp. n., male (32); M. (Sc.) styxianus sp. n., male (33); M. (Sc.) edithensis sp. n., male (34); M. (Sc.) tooloomensis sp. n., male (35); Penicillidmus masseyensis sp. n., male (36); P. unicolor sp. n., male (37).

FIGURES 62 – 63. Distribution of Microscydmus (Scydmomicrus subgen. n.) (62) and Penicillidmus gen. n. (63). Microscydmus (Scydmomicrus) australiensis Franz (62 a); M. (Sc.) nasicornis Franz (62 b); M. (Sc.) capitiseboraci sp. n. (2 c); M. (Sc.) queenslandicus sp. n. (62 d); M. (Sc.) styxianus sp. n. (62 e); M. (Sc.) edithensis sp. n. (62 f); M. (Sc.) tooloomensis sp. n. (62 g); Microscydmus (Sc.) sp. (62 h); Penicillidmus masseyensis sp. n. (63 a); P. unicolor sp. n. (63 b); Penicillidmus sp. (63 c).