Copelatus kietensis, Hájek & Shaverdo & Hendrich & Balke, 2021

Hajek, Jiri, Shaverdo, Helena, Hendrich, Lars & Balke, Michael, 2021, A review of Copelatus diving beetles from the Solomon Islands, reporting the discovery of six new species (Coleoptera, Dytiscidae, Copelatinae), ZooKeys 1023, pp. 81-118 : 81

Copelatus kietensis sp. nov. Figures 3 , 17

Type locality.

Papua New Guinea: Autonomous Region of Bougainville, Kieta .

Type material.

Holotype: ♂, labelled: " Papua New Guinea: Bougainville, / Kieta , 520 m, 12.vi.2008, 06.12.955S / 155.29.775E, Posman, (PNG180) [p] // HOLOTYPE ♂ / COPELATUS / Copelatus kietensis sp. nov. / Hájek, Shaverdo, Hendrich & Balke det. 2020 [red label, p]" ( ZSMG) .

Description of male holotype.

Habitus: Elongate, oblong-oval, broadest before mid-length of elytra; body moderately convex in lateral view. Body outline continuous, with only indistinct discontinuity between pronotum and elytra. Dorsal surface shiny (Fig. 3 ).

Colouration: Head including appendages ferruginous, darkened along eyes; pronotum black with ferruginous anterior angles; scutellar shield ferruginous translucent; elytra black with large irregular subapical testaceous spots; legs ferruginous, hind legs somewhat darker than preceding ones; ventral part of head and prosternum ferruginous, metaventrite, metacoxa and abdominal ventrites darker, blackish brown.

Head: Moderately broad, ca. 0.60 × width of pronotum, trapezoidal. Anterior margin of clypeus indistinctly concave. Antenna with antennomeres long and slender. Reticulation consisting of moderately deeply impressed polygonal isodiametric meshes. Punctation double, consisting of coarse setigerous punctures, and very small punctures spread sparsely on surface; row of coarse punctures present around inner margin of eyes, several punctures present at frontal level of eyes, and anterolaterally to eyes in fronto-clypeal depressions.

Pronotum: Transverse (width/length ratio = 2.79), broadest between posterior angles, lateral margins moderately curved. Sides with lateral beading very thin but distinct, except for anterior angles. Reticulation similar to that of head. Punctation similar to that of head; rows of coarse setigerous punctures present along anterior margin, laterally in longitudinal depression close to sides, several punctures present also in basolateral depressions along basal margin. Disc of pronotum laterally with short, irregularly, and sparsely distributed longitudinal strioles; several strioles present also in depressions close to posterior angles. Centre of disc with superficial medial longitudinal groove.

Elytra: Base of elytra as broad as pronotal base; lateral margins of elytra slightly diverging in basal third, distinctly narrowing in apical half. Eleven discal and a submarginal longitudinal striae present on each elytron: stria 1 shallow, largely fragmented in basal fourth of elytral length and ending approximately before apical fourth of elytral length; striae 2 and 3 shallow, absent at base; striae 4-9 complete; stria 10 absent at base; stria 11 ending at apical fifth of elytra; all odd striae generally shortened apically. Submarginal stria shallow, starting at approximately elytral mid-length. Surface reticulation similar to that of head and pronotum, meshes slightly smaller and less impressed. Punctation double, consisting of row of coarse setigerous punctures along elytral striae 4, 6, 8, and along lateral margin of elytra, and very fine sparsely distributed punctures.

Legs: Protibia simple, slightly broadened anteriorly, club shaped. Pro- and mesotarsomeres 1-3 distinctly broadened, with adhesive setae on their ventral side. Anterior protarsal claw broad basally, strongly curved in apical third.

Ventral side: Prosternum sinuate anteriorly, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, apex obtuse; process distinctly bordered laterally; reticulation consisting of shallow, hardly perceptible polygonal meshes. Metaventrite with microsculpture consisting of polygonal meshes; lateral parts of metaventrite ("metasternal wings") tongue-shaped, slender. Metacoxal lines well impressed, nearly complete, absent only close to metaventrite. Metacoxal plates covered with long, deep longitudinal strioles; reticulation consisting of elongated, longitudinal polygonal meshes. Metacoxal processes rounded and indistinctly incised at posterior margin. Abdominal ventrites I and II with longitudinal strioles; ventrites III and IV with oblique strioles laterally. Tuft of setae present antero-medially on ventrites III-V; ventrite VI with setigerous punctures laterally on either side. Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrites I and II, oblique on ventrite III and transverse on ventrites IV-VI. Punctation consisting of fine, sparsely distributed punctures; punctures coarser and denser laterally on apical ventrite.

Genitalia: Median lobe of aedeagus (Fig. 17 ) sickle-shaped, with pointed apex and distinct rugose surface sculpture visible in lateral view (Fig. 17A, B ); consisting of dorsal and ventral sclerites; dorsal sclerite divided into two parts of different shape in apical half, left part with lateral margin slightly curved and apex broadly pointed (Fig. 17C ); ventral sclerite with left part strongly sclerotised, its apex in shape of a small hook visible in lateral left view (Fig. 17B ), right part less sclerotised; apexes of dorsal and ventral sclerites elongate, more or less pressed together.

Lateral lobes (parameres) of narrow triangular form, with almost straight setigerous dorsal margin; setae numerous, dense, and strong distally, and distinctly less numerous, weaker, and sparser basally (Fig. 17D ).

Female. Unknown.

Measurements.

TL: 6.3 mm. TL-h: 5.7 mm. MW: 3.1 mm.

Differential diagnosis.

Based on the presence of 11 dorsal striae + a submarginal stria, the new species can be classified within C. trilobatus species group, see under C. baranensis sp. nov. Copelatus kietensis sp. nov. differs from all species of the C. trilobatus group by combination of body length, dorsal surface colouration and the shape of the male genitalia. In particular, C. kietensis sp. nov. differs from the sympatric C. bougainvillensis sp. nov. in larger body size, broader and more oval habitus, dark colouration of the elytra with testaceous subapical spots, as well as in structure and setation of the male genitalia (cf. Figs 16 , 17 ).

Etymology.

The species is named after Kieta, a port town located on the eastern coast of Bougainville Island, where it was collected. The specific epithet is an adjective in the nominative singular.

Distribution.

The species is known so far only from the type locality on the eastern coast of the Bougainville Island .

Habitat.

Unknown.

Figures

Figure 16. Male genitalia of Copelatus bougainvillensis sp. nov. (holotype) A median lobe in lateral view, right side B median lobe in lateral view, left side C median lobe in ventral view D left paramere in external view. Scale bar: 0.5 mm.

Figure 17. Male genitalia of Copelatus kietensis sp. nov. (holotype) A median lobe in lateral view, right side B median lobe in lateral view, left side C median lobe in ventral view D left paramere in external view. Scale bar: 0.5 mm.

Figures 3, 4. Habitus of Copelatus 3 C. kietensis sp. nov. (holotype; TL: 6.3 mm) 4 C. laevipennis sp. nov. (holotype; TL: 6.9 mm).