Eurycyphon castaneus, Zwick, Peter, 2015

Zwick, Peter, 2015, Australian Marsh Beetles (Coleoptera: Scirtidae). 8. The new genera Cygnocyphon, Eximiocyphon, Paracyphon, Leptocyphon, Tectocyphon, and additions to Contacyphon de Gozis, Nanocyphon Zwick and Eurycyphon Watts, Zootaxa 3981 (4), pp. 451-490 : 471-473

Eurycyphon castaneus , n. sp.

( Figs. 61–64 )

Type material. ♂ holotype: 31.53S 151.32E Barrington Tops Dilgry R. NSW 26.Nov.1985 C.Reid on Tree Ferns & Nothofagus ( ANIC).

Habitus. BL 3.1mm, BL/BW ~1.6. Surface strongly shining, pilosity sparse, semi-erect. Punctures on head, pronotum, and scutellum are widely spaced, very fine, almost obsolete. Punctures on the elytra are large, deep, widely spaced. The dorsal face is chestnut brown, underside, femora and bases of antennae orange-brown, tibiae and antennomeres 4–11 infuscate. Antennal base unmodified, segment 4 is the longest of all, distal antennomeres about 1.5x longer than wide. Mandibles concealed. Pronotum twice as long in the middle as along the convergent sides, central 3/5 of front margin straight, bent forward on sides, the blunt front angles projecting.

Male. T8 with large caudally widening plate. The short apodemes converge a little and are connected by an angular transverse sclerite. Caudal margin of plate flipped forward in preparation, on either side of a shallow notch a few pegs ( Fig. 61 ). S8 not noticed. T9 is narrower than T8, the parallel apodemes are connected by a medially interrupted arched sclerite. The bare plate is membranous and unpigmented, the distal margin is only faintly visible ( Fig. 62 ). Base of S9 not visible, the transparent caudal lobes bear a few setae ( Fig. 64 ). Tegmen a V-shaped sclerite, caudolaterally with long straight parameres. Two small triangular plates with serrate edges are attached to the base. The distal main part of each paramere is longitudinally folded and surrounds the penis laterally. The outer margin is sclerotized and well defined while the medial edge is soft and vague. The terminal section is an elongate lobe with rough surface and finely frazzled apex ( Fig. 64 ). Penis ( Fig. 63 ) with long rectangular pala. The trigonium is a stout flat sclerite, slightly waisted before the rounded caudal margin. It bears a subterminal hollow hook. The parameroids are very wide at the base and end in a long, concave, hollow spine. Their medial edge curves around the trigonium, the external edge has two knee-like angles.

Female. Unknown.

Note. The pegs on T8 suggest a close relationship with E. tomweiri , see account of that species. I am uncertain about the true nature of the serrate triangular plates which might provide additional evidence for the suggested relationship. However, their attachment to the sclerite is not clearly visible and the plates lie in the area where, in other species, the styli occur on a membrane.

Etymology. The colour of the dorsal side suggested the adjectival name, Latin castaneus , chestnut-brown.

Figures

FIGURES 61 – 67. Eurycyphon spp., males, IV. E. castaneus, n. sp.: 61, T 8; 62, T 9; 63, penis; 64, tegmen, with S 9 in the background; 68 – 70 and 71 – 73 to the same scale, respectively. E. tomweiri, n. sp.: 65, T 8, with enlarged detail of caudal edge; 66, T 9, apodemes of S 9 in centre visible by transparency; 67, penis and tegmen, superimposed. All to the same scale. pd, parameroid; pe, paramere; st, presumed stylus; tr, trigonium.