Microscydmus (Scydmomicrus) australiensis 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 : 18-19

Microscydmus (Scydmomicrus) australiensis Franz

( Figs. 20 , 29 , 38 , 42 , 46 , 50 , 62 )

Microscydmus australiensis Franz, 1975: 271 .

Material studied. Holotype: ♀: four labels: "Trapped by sticky seeds / of Pisonia brunoniana / Cairns dist.,: F. P.

Dodd" [white, printed], " Microscydmus / australiae [sic!] m. / det. H. Franz" [white, handwritten and printed], " Typus " [red, handwritten], " SAMA Database / No. 25-037045" ( SAM).

Revised diagnosis. Female: body uniformly yellowish-brown; frons subtriangular; punctures on head inconspicuous, only slightly more distinct than those on pronotum; BL <0.60 mm; pronotum 1.2x broader than head, with ante-basal transverse groove; EI 1.50. Males and their diagnostic characters unknown.

Redescription. Body of female ( Fig. 20 ) moderately convex, elongate and slender, with moderately long appendages, BL 0.525 mm; cuticle glossy, body uniformly yellowish-brown with slightly lighter appendages, vestiture yellowish.

Head ( Fig. 38 ) subtrapezoidal, broadest at eyes, HL 0.075 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 0.200 mm; antennomeres I–II elongate, III–X transverse; XI as long as broad.

Pronotum in dorsal view oval, broadest near anterior third, PL 0.150 mm, PW 0.150 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 0.300 mm, EW 0.200 mm, EI 1.500; basal impressions short; elytral apices separately rounded. Punctures on elytral disc fine but slightly more distinct and denser than 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 a). NE Australia (N Queensland).

Remarks. Microscydmus australiensis is known from a single female only, which is most similar to the female of M. nasicornis . Both species have lightly pigmented bodies, similar proportions of body parts, distinctly subtriangular frons and unremarkable, fine punctures on the head dorsum. Microscydmus australiensis is distinctly smaller than M. nasicornis (BL 0.525 mm vs. 0.625 mm) and has broader head in relation to pronotum (PW/HW 1.2 vs. 1.4). Microscydmus australiensis 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 in M. australiensis the pronotum is as long as broad (slightly broader than long in M. capitiseboraci ); the elytral index is low (EI 1.500 vs. 1.710 in M. capitiseboraci ); and the ratio EL/PL is also remarkably low (2.000 vs. 2.400 in M. capitiseboraci and in M. queenslandicus , while in M. styxianus EL/PL is as high as 2.540);

- 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. australiensis vs. dense and fine punctures forming fine transverse wrinkles in M. edithensis ); and distinctly smaller body (0.525 mm vs. 0.650 mm);

- from M. tooloomensis in the presence of the transverse ante-basal impression on the pronotum (absent in M. tooloomensis ); and slightly shorter body (BL 0.525 mm vs. 0.600 mm).

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 38 – 41. Head capsule in dorsal (38, 40), dorso-posterior (39) and lateral (41) views. Microscydmus (Scydmomicrus) australiensis Franz, female (38); M. (Sc.) capitiseboraci sp. n., male (39); Penicillidmus sp., female (40 – 41). Abbreviations: cl, clypeus; fr, frons; gen, gena; lb, labrum; md, mandible; mn, mentum; mxp, maxillar palpus; nr, neck region; oc, occipital constriction; occ, occipital constriction; tm, temple; vt, vertex.

FIGURES 42 – 45. Head capsule in ventral (42, 45), and antero-ventral (43 – 44) views. Microscydmus (Scydmomicrus) australiensis Franz, female (42); M. (Sc.) capitiseboraci sp. n., male (43); M. (Sc.) tooloomensis sp. n., male (44); Penicillidmus sp., female (45). Abbreviations: alc, anterior arm of longitudinal carina; bst, basistipes; cd, cardo; fo, foramen occipitale; fr, frons; gal, galea; gp, gular plate; gs, gular suture; hr, hypostomal ridge; lac, lacinia; lb, labrum; lg, ligula; lp, labial palpus; md, mandible; mn, mentum; mst, mesostipes; mxp 1 – 4, maxillary palpomere I – IV; plc, posterior arm of longitudinal carina; ppf, palpifer; ptp, posterior tentorial pit; smn, submental carina; smn, submentum; tc, transverse carina.

FIGURES 46 – 49. Prothorax in ventral view. Microscydmus (Scydmomicrus) australiensis Franz, female (46); M. (Sc.) capitiseboraci sp. n., male (47); M. (Sc.) tooloomensis sp. n., male (48); Penicillidmus sp., female (49). Abbreviations: hy, hypomeron; hyr, hypomeral ridge; nss, pronotosternal suture; pcc, procoxal cavity; pcs, procoxal socket; pf, profurcal fovea; plp, postero-lateral brush; psp, prosternal intercoxal process.

FIGURES 50 – 53. Pterothorax in ventral view. Microscydmus (Scydmomicrus) australiensis Franz, female (50); M. (Sc.) capitiseboraci sp. n., male (51); M. (Sc.) tooloomensis sp. n., male (52); Penicillidmus sp., female (53). Abbreviations: aest 2, mesanepisternum; ai, asetose impression of mesoventrite; ar, anterior ridge of mesoventrite; cl, coxal line; lmfa; lateral metafurcal arm; mscc, mesocoxal cavity; mscs, mesocoxal socket; msff, mesofurcal fovea; msp, mesocoxal projection; msvp, mesoventral intercoxal process; mtvp, metaventral intercoxal process; pl, posterior lobe of mesocoxal projection; pre, prepectus; sp, spermatheca; v 3, metaventrite.

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).