Austrelatus securiformis, 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

28. Austrelatus securiformis sp. nov.

Figs 38 , 42 , 83 , 93

Type locality.

Indonesia: Papua Province: Puncak Regency, S Iratoi, hunting camp, 03°16'48.6"S, 137°20'02.9"E, 150 m a.s.l.

Type material.

Holotype: male "Indonesia: Papua, S Iratoi, hunting camp, 150 m, 28.v.2015, -3,2801 137,3341, Sumoked (PAP042)", “7230” [green text] (MZB).

Description.

Body size and form: Beetle small, with oblong-oval habitus (Fig. 38 ).

Measurements: Holotype: TL 5.3 mm, TL-H 4.8 mm, MW 2.65 mm, TL/MW 2; PL 0.8 mm, PW 2.3 mm, PL/PW 0.35; DBE 0.9 mm, DBE/PW 0.39.

Colouration: Dorsally piceous, with yellowish brown head, pronotal sides, and an apical spot on elytron (Fig. 38 ).

Head yellowish brown, darker narrowly behind eyes. Pronotum piceous on disc and paler towards sides, yellowish brown on them, yellow at anterior angles. Elytron piceous, with a distinct, elongate, yellow apical spot. Scutellum piceous. Antennae, other head appendages, and legs proximally yellow; legs darker distally, yellowish brown, especially metalegs. Venter brown, with paler prosternum.

Surface sculpture: Elytron with 6 complete dorsal striae; submarginal stria present but interrupted, apical: 6+1 (Fig. 38 ).

Head without strioles, with dense punctation (spaces between punctures 1-3 × size of punctures); punctures relatively coarse (diameter of punctures usually equal to diameter of microreticulation cells or larger than it); head with a row of 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 strong. Pronotum with strioles laterally at posterior margin, especially in posterolateral angles; with fine longitudinal wrinkles at posterior margin; pronotal punctation distinctly 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 6 dorsal striae; striae 1-4 and 6 complete, stria 5 usually shortly reduced basally; submarginal striae weakly developed, present apically, interrupted. Elytron with fine punctation and distinct microreticulation. Ventral part with fine, inconspicuous punctation, invisible on metaventrite and metacoxae and more distinct on abdominal ventrites; prosternum smooth medially; metaventrite and metacoxae with distinct microreticulation; on abdominal ventrites microreticulation weak; 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 distinct 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 narrowly rounded anteriorly, slightly convex medially; blade of prosternal process relatively narrow, convex in middle.

Male: Protibia straight, not modified. Proclaws subequal in length, relatively short, curved downwards basally. Median lobe of aedeagus with two lobes of dorsal sclerite rather narrow, left dorsal lobe shorter that right one; in lateral view, apex of left dorsal lobe slightly curved upwards, with small crest; left dorsal lobe dorsally with distinct denticulation (spinulae) visible also in lateral left view; right dorsal lobe with small, indistinct, elongate median impression and modified apex: relatively large, swollen, rounded; left lobe of ventral sclerite with its sclerotised area large, curved to left, axe-shape truncate apically, distinctly shorter than right ventral lobe and dorsal lobes. Paramere with setae not divided into distal and proximal; more distally situated setae slightly denser than more proximal ones (Fig. 42 ).

Female: Unknown.

Affinities.

In dorsal colouration and elytron with 6+1 striae, the species is similar to A. testegensis sp. nov. but differs from it in absence of strioles between the elytral striae and shape of the proclaws and median lobe.

Etymology.

The species is named for the axe-like apex of the left ventral lobe of the median lobe. The name is Latin word combination securis and forma. It is an adjective in the nominative.

Distribution.

New Guinean endemic. Indonesia: Papua Province: Puncak Regency. The species is known only from its type locality (Fig. 83 ).

Habitat.

The species was collected in a forest pool (Fig. 93 ).

Figures

Figure 42. Austrelatus securiformis 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 83. Map of New Guinea showing distribution of seven Austrelatus species.

Figure 93. Habitat of Austrelatus species, Indonesia: Papua, S Iratoi, forest pool, (PAP 042): type locality of A. securiformis sp. nov. and habitat of A. rouaffer sp. nov. and A. nadjae sp. nov. Photograph by MB.

Figures 36 - 39. Habitus and colouration of 36 Austrelatus neoguineensis (Zimmermann, 1919), lectotype 37 A. mirificus sp. nov. 38 A. securiformis sp. nov. 39 A. testegensis sp. nov.