Austrelatus sandaunensis, 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

26. Austrelatus sandaunensis sp. nov.

Figs 69 , 73 , 84

Type locality.

Papua New Guinea: Sandaun, Mianmin, 04°53.292'S, 141°34.118'E, 670 m a.s.l.

Type material.

Holotype: male "Papua New Guinea: Sandaun, Mianmin, 670 m 20.x.2008, 4.53.292S 141.34.118E, Ibalim (PNG 191)" (ZSM).

Paratypes: 7 males, 4 females with the same label as the holotype (NHMW, ZSM). 1 female "Papua New Guinea: Sandaun, Mianmin, 670 m, 22.x.2008, 04.53.329S 141.35.263E S. Ibalim PNG189" (ZSM). 1 male "Papua New Guinea: Sandaun, Mianmin (river), 1080 m, 24.x.2008, 04.55.780S 141.38.185E, Ibalim (PNG 195)", “3773” [green label] (ZSM). 1 male "Papua New Guinea: Sandaun, Mianmin (pool), 1080 m, 24.x.2008, 04.55.780S 141.38.185E, Ibalim (PNG 196)" (ZSM). 1 male, 1 female "Papua New Guinea: Sandaun, Mianmin (river), 700 m, 21.x.2008, 04.52.858S 141.31.706E Ibalim (PNG 197)" (ZSM). 3 males "Papua New Guinea: Sandaun, Mianmin (pool), 700 m, 21.x.2008, 04.52.858S 141.31.706E, Ibalim (PNG 198)" (NHMW, ZSM).

Description.

Body size and form: Beetle medium-sized, with oblong-oval habitus (Fig. 69 ).

Measurements: TL 5.1-6 mm, TL-H 4.6-5.35 mm, MW 2.5-3 mm, TL/MW 2-2.04; PL 0.75-0.9 mm, PW 2.2-2.5 mm, PL/PW 0.34-0.36; DBE 0.9-1 mm, DBE/PW 0.39-0.41.

Holotype: TL 5.6 mm, TL-H 5.1 mm, MW 2.75 mm, TL/MW 2.04; PL 0.85 mm, PW 2.45 mm, PL/PW 0.35; DBE 0.95 mm, DBE/PW 0.39.

Colouration: Dorsally piceous, with yellowish red head, narrow pronotal sides and a basal band and one apical spot on elytron (Fig. 69 ).

Head yellowish red to reddish brown, piceous narrowly behind eyes. Pronotum dark brown to piceous on disc and paler towards sides, yellowish red on them. Elytron piceous, with three yellowish red to reddish brown basal spots, usually confluent, forming a basal band, not reaching suture and lateral margin; first spot between striae 1 and 3 vague or absent; therefore, band usually formed by two more lateral spots; elytron with a distinct, small, elongate spot apically. Scutellum yellowish red to dark brown. Antennae and other head appendages yellow. Pro- and mesolegs yellow and metalegs yellowish red proximally and darker distally. Venter yellowish red to brown, sometimes darker medially and paler laterally, especially on abdominal ventrites; prosternum yellowish red.

Surface sculpture: Elytron with 11 complete dorsal striae; submarginal stria present: 11+1 (Fig. 69 ).

Head without strioles, with rather dense punctation (spaces between punctures 1-2 × size of punctures); punctures relatively coarse (diameter of punctures equal to or larger than diameter of microreticulation cells); head with a row of coarse setigerous punctures along inner margin of each eye and a short row at frontal angle of each eye; a slightly longer puncture row forms fronto-clypeal depression at each head side; microreticulation distinct. Pronotum usually with several strioles at posterior margin or rather in posterolateral angles; with fine longitudinal wrinkles at posterior margin; pronotal punctation finer than on head; setigerous punctures form a row along pronotal margins, absent in posterior middle; disc of pronotum with indistinct longitudinal median scratch. Pronotum with distinct microreticulation. Elytron with 11 dorsal complete striae, often with fine, single strioles basally between striae 10 and 11; odd striae shortly reduced apically; submarginal striae present, weakly developed, short, apical, interrupted. Elytron with fine punctation and microreticulation. Ventral part with fine, inconspicuous punctation, invisible on metaventrite and metacoxae and weak on abdominal ventrites; prosternum smooth medially; metaventrite and metacoxae with distinct microreticulation; on abdominal ventrites microreticulation fine; metacoxal plates with numerous, strongly impressed 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 fine punctation that sparser medially and forms a dense, rugose lateral area at each side.

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

Male: Protibia straight, not modified. Proclaws simple, relatively long, equal. Median lobe of aedeagus with two lobes of dorsal sclerite rather narrow, subequal; in lateral left view, left dorsal lobe with short, apical crest and weaker lateral crest; its apex more or less straight, pressed to right dorsal lobe; right dorsal lobe with weakly developed, inconspicuous median impression in right lateral view, more or less rounded apex and small crest on its left side where apex of left dorsal lobe placed in left lateral view. Lobes of ventral sclerite weakly sclerotised laterally visible in left and right lateral views, mostly membranous, straight apically; left ventral lobe distinctly shorter than right ventral lobe; sclerotised part of left ventral lobe long, thin, and straight apically in left lateral view. Paramere with setae not clearly divided into distal and proximal; sometimes few the most proximally setae standing something separately (Fig. 73 ).

Female: With coarser and denser dorsal punctation, especially on elytron. There are no striolated, matt forms.

Variability.

There is an insignificant variation in the colouration and dorsal striolation described above.

Affinities.

Based on shape of the median lobe, the species is very similar to A. toricelli sp. nov. but differs from it in complete 11 dorsal striae of elytron and different shape of the median lobe sclerites: differently shaped left dorsal lobe and left ventral lobe distinctly shorter that right ventral lobe.

Etymology.

The species is named after Sandaun Province. The name is an adjective in the nominative singular.

Distribution.

New Guinean endemic. Papua New Guinea: Sandaun Province. The species is known only from the Mianmin area (Fig. 84 ).

Habitat.

The species was collected in stream-side puddles.

Figures

Figure 73. Austrelatus sandaunensis 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 84. Map of New Guinea showing distribution of 14 Austrelatus species.

Figures 66 - 69. Habitus and colouration of 66 Austrelatus rouaffer sp. nov. 67 A. wanggarensis sp. nov. 68 A. vagauensis sp. nov. 69 A. sandaunensis sp. nov.