Prionocyphon papuanus, Zwick, 2015

Zwick, Peter, 2015, Three new Marsh Beetles (Col.: Scirtidae) from New Guinea and Java, Linzer biologische Beiträge 47 (2), pp. 1885-1895 : 1889-1891

Prionocyphon papuanus nov.sp. ( Figs 10-12 )

H o l o t y p e: Irian Jaya: Jayawijaya Langda 27.- 28.8.1992 leg. A.Riedel 2100-2300m (SMNS).

Habitus. BL 2.2mm, BL/BW ~1.5, HCW corresponds to 51% of BW. Regularly oval, fairly flat. Dorsal surface light brown, legs and antennomeres 1-3 yellowish, antennomeres 4 and 5 infuscate, more distal segments missing. Normal punctures on entire surface, those on head and pronotum equal, finer than on elytra. Pilosity semi-erect, a bit shaggy, yellowish.

The front of clypeus is straight in the middle above the labrum. On each side of the labrum the clypeus forms a rounded plate extending forward next to the flat scape which is distinctly larger. Scape flat, with sharp front edge. Pedicel small, inserted under the edge of the scape. Antennomere 3 minute, 4 (which tends to be the most slender antennal segment) only about twice as long as wide, antennomere 5 shorter and stouter, both with round cross section, neither flattened nor serrate. SAR ending where it meets the eye.

Lower face of head and thorax typical of the genus, head with small but distinct buttonhole-configuration. Prosternal process slender, about drop-shaped. Receiving mesoventral groove wide, U-shaped.

Pilosity differs between abdominal sternites. It is sparse and mainly composed of small sensilla with large insertion ring on S3. S4 bears a mixture of normal setae and sensilla. Numbers change successively on posterior sternites, S7 is densely covered by only setae. T7 is caudally wider than S7 and has two short apodemes. It bears the spiracle and is largely covered with hair-like microtrichia directed mediad on the sides, caudad along a middle strip. Near the caudal edge, much finer microtrichia are directed backward, forming a dense fringe along the edge. Very small true hairs with insertion rings are interspersed in this caudal region.

M a l e. T8 with short nearly straight stout apodemes connected by a strong basal sclerite, plate transverse, short. Caudal half and rear edge covered with microtrichia and minute socketed setae, a few longer setae along edge. S8 not developed. Apodemes of T9 more slender, converging but not connected. Plate entirely membranous, pale, hairless ( Fig. 10 ). S9 (half missing, Fig. 11 ) with slender base supported by paired sclerites, caudal half tongue-shaped, medially divided, densely covered with setae.

Tegmen and pala connected, forming a single compact ovoid structure with re-enforced rounded front edge ( Fig. 12 ). Parameres and styli originate laterally in the basal fourth at the level where trigonium and parameroids also originate. The parameres are slender sinuous rods with some apical setae, the styli are weak, long and straight processes with apical microtrichia-like frazzles. The contour of the large parameroids determines the ovoid overall shape of the genitalia. The parameroids wrap around the base of trigonium, caudally they lie along its sides. The trigonium is a flat bottle-shaped structure. The truncate narrow apex is divided, each lobe slightly extended sideways and beset with single large conical teeth. The endophallus shines through the base of the trigonium. On each side appears a pack of dense slightly divergent folds, possibly colourless slender teeth. More distally the endophallus is exposed on either side of the narrow part of trigonium. It shows numerous very delicate parallel folds ( Fig. 12 is diagrammatic in this respect!) which curve at the top where they are oriented centripetally, apparently around the terminal opening.

F e m a l e. Unknown.

Notes. The frontoclypeal lobes are shared with Australian Prionocyphon species (for illustrations, see WATTS 2010, ZWICK in prep.) but also with other genera, e.g., Mescirtes . Several of the Australian species also exhibit an intimate connection between tegmen and penis, and an armed endophallus with visible caudal opening (ZWICK, in prep.). The pattern of abdominal pilosity is close to the heterogenous pattern of many Australian species. In Table 1 of ZWICK (in prep.) the new New Guinean species would stand a few lines beneath P. storeyi WATTS, 2010.

E t y m o l o g y. The species name is an adjective describing the origin of the beetle.

Figures

Figs 10-12: Prionocyphon papuanus nov.sp., male: (10) ventral view of abdominal tip, segments 8 and 9 protracted; (11) S9, half missing; (12) tegmen and penis, superimposed. 10, 11 to same scale. ep, endophallus; pd, parameroid; pe, paramere; st, stylus; te, tegmen; tr, trigonium.