Austrelatus lembenensis, Shaverdo & Hájek & Hendrich & Surbakti & Panjaitan & Balke, 2023

Shaverdo, Helena, Hajek, Jiri, Hendrich, Lars, Surbakti, Suriani, Panjaitan, Rawati & Balke, Michael, 2023, Austrelatus gen. nov., a new genus of Australasian diving beetles (Coleoptera, Dytiscidae, Copelatinae), with the discovery of 31 new species from New Guinea, ZooKeys 1170, pp. 1-164 : 1

12. Austrelatus lembenensis sp. nov.

Figs 15 , 19 , 82

Type locality.

Papua New Guinea: East Sepik Province, Lembena, 04°56'58.4"S, 143°56'59.7"E, 198 m a.s.l.

Type material.

Holotype: male "Papua New Guinea: East Sepik, Lembena, 198 m, 3.ix.2009, 04°56'97.4"S 143°56'99.5"E, Ibalim & Pius (PNG241)" (ZSM).

Paratypes: 1 female with the same label as the holotype (ZSM). 1 male, 1 female "Papua New Guinea: East Sepik, Lembena, 198 m, 3.ix.2009, 04 46 [!] 974S 143.56.995E, Ibalim & Pius (PNG243)" (ZSM). 2 males "Papua New Guinea: East Sepik, Lembena, 136 m, 3.ix.2009, 04.56.911S 143.56.870E, Ibalim & Pius (PNG244)" (NHMW, ZSM). 1 male "Papua New Guinea: East Sepik, Lembena, 297 m, 8.ix.2009, 04.57.329S 143.57.297E, Ibalim & Pius (PNG247)", “6010” (ZSM). 2 females "Papua New Guinea: East Sepik, Lembena, 335 m, 10.ix.2009, 04 56.859S 143 59.375E, Ibalim & Pius (PNG250)" (NHMW, ZSM). 1 male, 2 females "Papua New Guinea: East Sepik, Lembena, 335 m, 10.ix.2009, 04.56.859S 143.57.379E, Ibalim & Pius (PNG251)" (NHMW, ZSM).

Description.

Body size and form: Beetle small, with rather elongate habitus (Fig. 15 ).

Measurements: TL 5-5.25 mm, TL-H 4.6-4.8 mm, MW 2.5-2.65 mm, TL/MW 1.98-2; PL 0.7-0.8 mm, PW 2.1-2.3 mm, PL/PW 0.33-0.4; DBE 0.9-0.95 mm, DBE/PW 0.41-0.43.

Holotype: TL 5.25 mm, TL-H 4.8 mm, MW 2.65 mm, TL/MW 1.98; PL 0.8 mm, PW 2.3 mm, PL/PW 0.4; DBE 0.95 mm, DBE/PW 0.41.

Colouration: Dorsally piceous, with reddish yellow head, pronotal sides, and basal band and apical spot on elytron (Fig. 15 ).

Head reddish yellow, dark brown behind eyes. Pronotum piceous, slightly paler anteriorly and laterally, with reddish yellow sides. Elytron piceous, slightly paler on disc and darker laterally, with reddish yellow basal band of different length but not reaching suture and lateral elytral margin; its anterior margin reaching elytron basally and its posterior margin not straight, sometimes vaguely notched; elytron with distinct, reddish yellow, elongate apical spot of medium size. Scutellum reddish yellow or piceous. Antennae and other head appendages yellowish brown. Pro- and mesolegs yellowish brown proximally and darker distally, especially metalegs. Venter brown to piceous, with paler prosternum. Teneral beetles paler.

Surface sculpture: Elytron without striae: 0+0, but with distinct puncture lines (Fig. 15 ).

Head without strioles, with relatively dense, even punctation (spaces between punctures 1-3 × size of punctures); punctures relatively large (diameter of punctures more or less equal to diameter of cells of microreticulation) but not coarse; head with a row of coarse setigerous punctures along inner margin of each eye and a very short row of less coarser punctures at frontal angle of each eye; a longer puncture row forms fronto-clypeal depression at each head side; a small uneven median depression probably due to some coarser punctures sometimes present; head with strong microreticulation. Pronotum without strioles but with thin longitudinal wrinkles at middle of posterior margin; pronotal punctation slightly finer and sparser than on head; coarse setigerous punctures form a broad row along pronotal margins, absent in posterior middle; disc of pronotum with indistinct short, thin, longitudinal median scratch. Pronotal microreticulation rather weakly impressed on disc. Elytron without elytral striae but with two very distinct puncture lines on disc and one laterally, their coarse punctures contiguous, especially those of discal lines; three additional lines of very sparse, coarse setigerous punctures can be seen between elytral lines and between lateral line and lateral margin; elytron with fine but rather dense and distinct punctation; microreticulation weak. Ventral part with extremely fine, scarce, inconspicuous punctation, invisible on metaventrite and metacoxae and more distinct on abdominal ventrites; prosternum smooth medially; metaventrite and metacoxae with weak microreticulation; on abdominal ventrites microreticulation almost invisible; metacoxal plates with more or less short longitudinal strioles, abdominal ventrites 1 and 2 with numerous, long, longitudinal strioles from margin to margin, on abdominal ventrites 3 and 4 strioles situated laterally and turn to middle, almost horizontal, abdominal ventrites 5 and 6 without strioles but with distinct punctation that sparser medially and forms a very dense lateral area at each side.

Structures: Head relatively broad. Pronotum short and broad; lateral margins distinctly convergent anteriorly. Base of prosternum slightly rounded anteriorly, strongly convex medially; neck of prosternal process strongly convex; blade of prosternal process small, strongly convex in middle.

Male: Protibia straight, not modified. Proclaws rather short, subequal in length: anterior claw slightly shorter than posterior one. Median lobe of aedeagus with two lobes of dorsal sclerite narrow; right dorsal lobe slightly longer than left one; in lateral view, apex of left dorsal lobe slightly curved downwards, with a small crest; left dorsal lobe dorsally with distinct denticulation (spinulae) visible also in lateral left view; apex of right dorsal lobe swollen, very broadly rounded. Left lobe of ventral sclerite with its sclerotised area visible laterally, well-developed, large, broad, shorter than right ventral lobe; its apex more or less rounded, not hooked. Paramere with setae not clearly divided into distal and proximal; more distally situated setae slightly denser than more proximal ones, sometimes with several the most proximal setae standing separately in right paramere (Fig. 19 ).

Female: Only form with smooth elytra present.

Affinities.

In general shape of median lobe, especially in shape of the sclerotised area of left ventral lobe and in shape of the lateral crest of the left dorsal lobe, the species is similar to A. rouaffer sp. nov., A. fojaensis sp. nov., and A. innominatus sp. nov. but it differs from them by elytron without striae, shape of the median lobe sclerites and colouration. In absence of the elytral striae and partly shape of the median lobe, it is similar to A. nadjae sp. nov. but differs from it distinctly more elongate habitus, less prominent yellow pattern, and different shape of the median lobe. There are two more species of the group known from Lembena area: A. neoguineensis and A. mirificus sp. nov. Both these species have distinct elytral striae. Austrelatus neoguineensis is larger and has two parts of dorsal sclerite of median lobe broader, with pointed apexes of bird beak-shape. Austrelatus mirificus sp. nov. is very similar in colouration and shape of the median lobe to A. nadjae sp. nov.

Etymology.

The species is named after its type locality, Lembena Village. The name is an adjective in the nominative singular.

Distribution.

New Guinean endemic. Papua New Guinea: East Sepik Province, Lembena area (Fig. 82 ).

Habitat.

The species was collected in stream-side puddles.

Figures

Figure 19. Austrelatus lembenensis sp. nov., median lobe A left lateral view B right lateral view C ventral view D left paramere in external view E right paramere in internal view. Scale bar: one unit - 0.1 mm (A-C).

Figure 82. Map of New Guinea showing distribution of 11 Austrelatus species.

Figures 14 - 17. Habitus and colouration of 14 Austrelatus adelbert (Megna et al., 2017) 15 A. lembenensis sp. nov. 16 A. nadjae sp. nov. 17 A. pseudoneoguineensis sp. nov.