Austrelatus neoguineensis (Zimmermann, 1919) 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

19. Austrelatus neoguineensis (Zimmermann, 1919) comb. nov.

Figs 11 , 36 , 40 , 82

Copelatus neoguineensis Zimmermann, 1919: 199-200; Zimmermann (1920b: 141); Guignot (1956: 55); Guéorguiev (1968: 25); Guéorguiev and Rocchi (1993: 160); Nilsson and Hájek (2023: 49).

Type locality.

"Neuguinea, Herbertshöhe” [Papua New Guinea: East New Britain Province, Kokopo, ca. 04°21′S, 152°16′E].

Type material.

Lectotype (by present designation): male [lacks left proleg and one paramere] “Herbertshöhe D.N. Guinea.", "Coll. Bennigsen", "Zimmermann det.", "Lectotype Copelatus neoguineensis Zimmermann, 1919 des. H. Shaverdo 2023" [red] (SDEI).

Paralectotypes: 1 female [beetle and one paramere (sic!) glued on pined triangular] "Neu Guinea" [hw by?Zimmermann], “Type” [round, hw by?Zimmermann], "Samml. A. Zimmermann", “Type” [red], " Copelatus neoguineensis " (ZSM). 1 male [without genitalia] “Herbertshöhe D.N. Guinea.", "Coll. Bennigsen", “TYPUS” [red], “Syntypus” [red], " Copelatus neo-guineensis Zimerm. [sic!] Type" [hw by?Zimmermann] (SDEI). 1 male [only median lobe, one paramere and right protarsus glued on pined card, beetle probably lost or the parts belong to the previous specimen] "Penis C. neoguin" [hw by?Zimmermann], "Samml. A. Zimmermann" (SDEI).

Notes.

The lectotype is designated for purpose of the stability of nomenclature, as the existing works do not allow undoubted identification of the species. Although five specimens are mentioned in the original description ( Zimmermann 1919: 200), we have found only three of them.

Additional material.

See Appendix 1.

Description.

Body size and form: Beetle medium-sized, with oblong-oval habitus (Fig. 36 ).

Measurements: TL 5.2-6.9 mm, TL-H 4.7-6.35 mm, MW 2.6-3.35 mm, TL/MW 2-2.06; PL 0.7-0.95 mm, PW 2.2-2.85 mm, PL/PW 0.32-0.33; DBE 0.9-1.25 mm, DBE/PW 0.39-0.44.

Lectotype: TL 6.45 mm, TL-H 5.9 mm, MW 3.2 mm, TL/MW 2.02; PL 0.9 mm, PW 2.85 mm, PL/PW 0.32; DBE 1.1 mm, DBE/PW 0.39.

Colouration: Dorsally piceous, with reddish yellow head, pronotal sides, and two basal and one apical spot on elytron (Fig. 36 ).

Head yellowish red to reddish brown, darker narrowly behind eyes. Pronotum reddish brown to dark brown on disc and paler towards sides, yellowish red to reddish brown on them. Sometimes only anterior and posterior margins medially dark. Elytron dark brown to piceous, with two yellow to reddish brown spots on elytral base: one between striae 2 and 4 and second between striae 4 and 6; sometimes these spots distinct, sometimes vague; second usually better developed but not reaching lateral elytral margin; sometimes spots confluent like a denticule band, seldom absent; elytron with more or less distinct elongate apical spot. Scutellum reddish brown to piceous. Antennae, other head appendages, and legs proximally yellow to yellowish red; legs darker distally, especially metalegs. Venter yellowish red to reddish brown, with paler prosternum. Teneral beetles paler.

Surface sculpture: Elytron with six more or less complete dorsal striae; stria 1 usually reduced basally and present only in apical elytral half; submarginal stria usually absent: 6+(0-1) (Fig. 36 ).

Head without strioles, with relatively sparse punctation (spaces between punctures 1-3 × size of punctures); punctures relatively fine (diameter of punctures usually smaller 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 but not strong. Pronotum usually with several strioles laterally or only in posterolateral angles, seldom without them; 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. Pronotal microreticulation rather weakly impressed. Pronotum sometimes with numerous strioles in females. Elytron with 6 dorsal striae; stria 1 usually reduced basally and present only in apical elytral half; striae 2, 4, 6 complete; striae 3 and 5 usually reduced or interrupted basally, seldom complete; submarginal striae usually absent, seldom present. Elytron with very fine, inconspicuous punctation and very weak microreticulation. Elytron sometimes with numerous strioles in females. 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, finely 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 rather 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, convex medially; blade of prosternal process relatively narrow, convex in middle.

Male: Protibia not straight, thinner proximally and broader medially and distally due to its slightly curved ventral margin. Proclaws relatively long, subequal. Median lobe of aedeagus with two lobes of dorsal sclerite broad, almost straight or slightly curved downwards apically; right dorsal lobe slightly longer and broader than left one, with a broadly pointed apex and large median membranous impression in right lateral view; in left lateral view, left dorsal lobe with a lateral longitudinal crest. Lobes of ventral sclerite weakly sclerotised laterally (visible in left and right lateral views), mostly membranous, subequal, strongly pressed together, usually slightly curved upwards apically; sclerotised part of left ventral lobe small, short, sometimes indistinct (in left lateral view). Paramere with setae not divided into distal and proximal, more or less uniform (Figs 11 , 40 ).

Female: Dimorphic. Some females have numerous thin, longitudinal strioles on elytra and pronotum that densely cover dorsal surface and make it matt. Ratio shiny: striolated is different in populations. Usually shiny forms are more numerous. E.g., 24: 2 in PNG54; 1: 1 38+37+?36/2013; only with strioles in 44/2013; 5: 3 in 33/2013; 3: 7 in PNG188; 16: 2 in PNG 115; 18: 7 in PNG27; 40: 2 in leg. Messer 26Mar.; 25: 5 in leg. Messer 14Feb.; 34: 8 in leg. Messer 7Feb.; 13: 7 in leg. Messer 14Jan.; 20: 26 in PNG196; 8: 27 in PNG198.

Variability.

The species demonstrates some variation in its dorsal colouration and variation in elytral striolation described above.

Affinities.

Based on general appearance and shape of the median lobe, the species is close to A. bormensis sp. nov., but also similar to A. pseudoneoguineensis sp. nov. See the differences under these species.

Distribution.

New Guinean endemic. Literature records: New Guinea ( Guignot 1956; Guéorguiev 1968) and PNG: the species is described from New Britain Island ( Zimmermann 1919, 1920b; Guéorguiev and Rocchi 1993); however, our study shows that the species is widespread in New Guinea, and especially numerous in Sandaun, East Sepik, and Madang provinces (Fig. 82 ).

Habitat.

In the Cyclops Mountains, it was collected in different kind of small and shallow pools and puddles alongside smaller forest streams. Around Mount Wilhelm, numerous specimens have been collected with flight intercept traps during the IBISCA project.

Figures

Figure 11. Austrelatus neoguineensis (Zimmermann, 1919) A, B median lobe in left lateral view at different magnifications, treated with lactic acid (see Materials and methods). Abbreviations: a dorsal sclerite aa left dorsal lobe ab right dorsal lobe b ventral sclerite ba left ventral lobe bb right ventral lobe c sclerotised area of left ventral lobe.

Figure 40. Austrelatus neoguineensis (Zimmermann, 1919), 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 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.