Austrelatus garainensis, 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

9. Austrelatus garainensis sp. nov.

Figs 60 , 64 , 83

Type locality.

Papua New Guinea: Morobe Province, Garaina, 07°51.032'S, 147°07.007'E, 720 m a.s.l.

Type material.

Holotype: male "Papua New Guinea: Garaina, 720 m, vi.2008, 07.51.032S 147.07.007E Ibalim & Sosanika PNG216" (ZSM).

Paratypes: PNG: Morobe: 122 males, 96 females with the same label as the holotype (BMNH, NHMW, ZSM). For additional paratypes see Appendix 1.

Description.

Body size and form: Beetle medium-sized, with oblong-oval habitus (Fig. 60 ).

Measurements: TL 5.4-6.2 mm, TL-H 4.6-5.9 mm, MW 2.7-3.25 mm, TL/MW 2-2.07; PL 0.8-0.9 mm, PW 2.3-2.7 mm, PL/PW 0.33-0.35; DBE 0.9-1.05 mm, DBE/PW 0.39.

Holotype: TL 6.2 mm, TL-H 5.6 mm, MW 3 mm, TL/MW 2.07; PL 0.85 mm, PW 2.55 mm, PL/PW 0.33; DBE 1 mm, DBE/PW 0.39.

Colouration: Dorsally piceous, with yellowish red head, pronotal sides and on elytron with three yellowish red basal spots or a posteriorly notched basal band, one apical spot, and often with narrow lateral band (Fig. 60 ).

Head yellow to reddish brown, piceous narrowly behind eyes. Pronotum dark brown to piceous on disc and paler towards sides, broadly yellow to reddish brown on them. Elytron piceous, with three rather distinct, yellow to reddish brown spots on elytral base: one between striae 1 and 3, second between striae 5 and 7 and third between striae 9 and 11; usually two latter spots confluent forming a posteriorly notched basal band; first spot sometimes vague or absent, seldom confluent with second; elytron with a distinct, elongate, small to large apical spot; sometimes a narrow lateral band present, confluent with apical spot. Scutellum yellow to brown. Antennae, other head appendages, and pro- and mesolegs proximally yellow, distally yellowish red; metalegs yellowish red, darker distally. Venter with yellowish red prosternum, dark brown meso- and metaventrites and metacoxae, and reddish brown abdominal ventrites; abdominal ventrites 5 and 6 with a yellowish red lateral spot on each side. Teneral beetles paler.

Surface sculpture: Elytron with 11 distinct, complete dorsal striae; submarginal stria present: 11+1 (Fig. 60 ).

Head without strioles, with rather dense punctation (spaces between punctures 1-3 × size of punctures); punctures relatively fine (diameter of punctures equal to 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 weak. Pronotum with several weak strioles on sides or with numerous distinct strioles covering even disc, with numerous, fine longitudinal wrinkles at posterior margin; pronotal punctation finer and denser 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 fine microreticulation. Elytron with 11 distinctly impressed dorsal striae; striae complete, not reduced basally; striae 1, 3, 5, 7, and 9 reduced apically; submarginal striae present, long, well-developed, reaching ½ or more of elytron. 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 weak microreticulation; on abdominal ventrites microreticulation almost invisible; 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 very sparse 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 broadly rounded anteriorly, convex medially; blade of prosternal process long, narrow, convex in middle.

Male: Protibia straight, not modified. Proclaws rather long, subequal in length. Median lobe of aedeagus with two lobes of dorsal sclerite rather narrow; left dorsal lobe distinctly shorter that right one, with long lateral crest; apex of left dorsal lobe curved downwards and not to left; its dorsal surface without denticulation, it invisible in left lateral view due to strong curvature downwards; right dorsal lobe with distinct, but shallow, elongate median impression; apex of right dorsal lobe elongate, less swollen, rounded; lobes of ventral sclerite almost completely sclerotised, only with narrow membranous areas medially; sclerotised area of left ventral lobe as long as left dorsal lobe, with long, thin slightly curved to left apex, well visible in lateral left and ventral views; right ventral lobe with large sclerotised area, flat, not protruding, not covering left ventral lobe. Paramere with setae distinctly divided into distal and proximal; proximal setae sparser and shorter than distal (Fig. 64 ).

Female: Dimorphic: with elytron punctate as in males or elytron with denser punctation and additionally to it with very tiny strioles between striae. There are no strongly striolated, matt forms. The striolated females very seldom, ratio: 26:2 in PNG220; 91:5 in PNG116; 46:11 in PNG117.

Variability.

There is a variation in the body size, colouration and dorsal striolation. Pronotum with numerous strioles is characteristic for the specimens from Central Province (PNG183). These specimens are also the smallest ones.

Affinities.

In body shape, elytral striolation and dorsal colouration, the species is similar to A. vague sp. nov. and A. kaszabi . The species can be distinguished from them by shape of its median lobe sclerites, especially by the strongly sclerotised ventral sclerite and the sclerotised area of the left ventral lobe very well visible in lateral left and ventral views, with its apex curved to left like a slight hook.

Etymology.

The species is named after Garaina Village. The name is an adjective in the nominative singular.

Distribution.

New Guinean endemic. The species is widespread in PNG: Morobe, EHL, Central, National Capital District, and Milne Bay provinces (Fig. 83 ).

Habitat.

Unknown.

Figures

Figure 64. Austrelatus garainensis 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.

Figures 58 - 61. Habitus and colouration of 58 Austrelatus baliem sp. nov. 59 A. kaszabi (Guignot, 1956), holotype 60 A. garainensis sp. nov. 61 A. mimika sp. nov.