Petrocyphon bonang, Zwick, 2016

Zwick, Peter, 2016, Australian Marsh Beetles (Coleoptera: Scirtidae). 9. The relations of Australasian Ypsiloncyphon species to their Asian congeners, additions, mainly to Petrocyphon and Prionocyphon, and a key to Australian genera of Scirtinae, Zootaxa 4085 (2), pp. 151-198 : 162-165

Petrocyphon bonang , n. sp.

( Figs 28–33 )

Type material. Holotype ♂: 37°15'32''S 148°43'49''E GPS 635m VIC: Bendoo-Bonang SF: Bonang Hwy. 56km NNE Orbost 11 Jan-11 Feb 2005 C.Lambkin, N.Starick / Malaise in tree ferns in gully ANIC Bulk Sample No: 2619 ( ANIC).

Additional material studied. 1 ♀ with the same data as the holotype ( ANIC).

Habitus. Relatively large and stout, with parallel elytra, small pronotum, head with large projecting eyes. BL 2.2 mm, BL/BW~1.65, PW ~62% of BW, HCW ~52% of BW. Uniformly light brown, pilosity yellowish, semierect. Head and pronotum with granular punctures, coarse on head, finer on pronotum, very fine on scutellum. Elytra with normal fairly large punctures which are, in anterior half, about one diameter apart in longitudinal direction but in horizontal direction locally even less, in places approaching transverse rows. Basal third of elytra without depression.

Head about as long as wide across the eyes, genae and temples each ~1/5 length of eye. Labrum slightly bilobed, the sharp slender mandible tips projecting, other mouthparts not studied. Pronotum strongly transverse, front angles rounded but distinct, front margin between them straight, sides strongly rounded, margined, the fine ridge freely visible. The barely marked rear angles wider apart than the front angles, rear margin strongly projecting towards the scutellum which is an equilateral triangle. Legs slender, short, unmodified.

Underside. Prosternal process elongate drop-shaped, visible part of receiving mesoventral groove a deep smooth oval. Abdomen wide, narrowing caudally, S7 broadly rounded.

Male. Antenna slender, not strikingly thickened, antennomere 9 extends to almost half body length; antennomeres 10 and 11 missing from holotype.

Plate of T8 transverse, beset with microtrichia mixed with socketed hairs of similar size, also along truncate rear margin. Apodemes short, straight, not connected ( Fig. 28 ). S8 not developed. T9 with longer, in front slightly curved, unconnected apodemes. The bare colourless soft plate without defined shape ( Fig. 29 ). Of S9 only the pilose bilobed rear margin is visible. Tegmen with rounded front margin and long parallel base, caudally widening and supporting slender gently curved parameres, each divided into two branches. The long medial branch has an elongate subterminal area covered with minute sensilla and, near midlength, a strongly sclerotized outwardly curved triangle. The shorter lateral branch is faintly concave and ends in a straight slender cone. Distal third of left branch with numerous spines, the corresponding section of the right branch a bit swollen, without distinct spines ( Fig. 30 ). Penis very long and slender, gently curved dorsoventrally and therefore seemingly a little asymmetrical in the preparation. The concave front end with prominent lateral corners is the widest part of the penis. The pala is over 3 times longer than the distal area with trigonium and parameroids. Trigonium supported by divergent basal arms separated by a semicircular notch, the gently curved pointed apex long and slender. The straight slender parameroids end in a slender cone which is beset with fine sensilla caudally from a low projection ( Fig. 31 ).

Female (presumed). Similar to male, except eyes a little smaller and antenna thinner and slightly shorter. Abdominal sternites and ovipositor not modified, bacula with recurrent branchlet. S8 not visible. The vulvar sclerite ( Fig. 32 ) seems to be a folded wide tube, details not visible. The bursella bears two large sclerite rings ~310 µm in diameter. Periphery thick, composed of several superimposed layers of sclerotized meshes, sharply delimited from the flat centre of the disc which is covered with small approximately hexagonal meshes ( Fig. 33 ).

Note. Several species in the tasmanicus -group have branched parameres and an undivided trigonium, but all differ clearly in their genitalia. By penis and tegmen P. phoenix Watts and P. julianae Zwick are most similar but, among many other details, they differ strikingly by the complex structure of their shorter paramere branch. Clearing the present specimen was only partly successful, muscle fibers remain and obscure details of segments 8 and 9. The female bursal rings agree with those of P. julianae which differs in the form of the vulvar sclerite and by a large notch in T7.

Etymology. Named after the type locality, the specific epithet is a noun in apposition.

Figures

FIGURES 28 − 33. Petrocyphon bonang n. sp. 28, male T 8; 29, male T 9; 30, tegmen, ventral view; 31, penis; 32, vulvar sclerite, lateral, diagrammatic; 33, bursal ring. Abbreviations: ba, basal arm of trigonium; pa, pala; pd, parameroid; pe, paramere; te, tegmen; tr, trigonium. 28, 29, 32 and 30, 31 to the same scales, respectively.