Austrelatus pseudooksibilensis, 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

22. Austrelatus pseudooksibilensis sp. nov.

Figs 24 , 25 , 28 , 82 , 87

Type locality.

Indonesia: Papua Province: Nabire Regency, road Nabire-Enarotali, 62nd km, 250 m a.s.l.

Type material.

Holotype: male "West New Guinea/Paniai Prov./IR 22 track Nabire-Ilaga km 62 250 m, 24.7.1991, forest pools leg: Balke & Hendrich" (ZSM).

Paratypes: IN: Papua Province: Nabire Regency: 23 males, 4 females, with the same label as the holotype (MZB, NHMW, ZSM). 2 males, 3 females "Ir 23-W. New Guinea, track Nabire-Ilaga KM 62, 250 m, 24.vii.1991 Balke & Hendrich leg." (ZSM). 2 males, 4 females "West New Guinea/Paniai Prov./IR 20 track Nabire-Ilaga KM 59, ca.750 m, 18.7.1991 leg: Balke & Hendrich leg." (ZSM). 2 males "West New Guinea/Paniai Prov./IR 18 River n. Nabire, 2 m, 15.7.1991 leg: Balke & Hendrich leg." (ZSM). 10 males, 16 females "Irian Jaya: Paniai Prov. road Nabire - Ilaga, km 65, 29.8.1996, 250 m leg. M. Balke (96 # 6)" (MZB, NHMW, ZSM).

West Papua Province: Teluk Wondama Regency: 2 males, 1 female "Indonesia: West Papua, DMP, Wasior, 7.-10.i.2001, Riedel leg." (NHMW, ZSM). 1 male "Indonesia: Irian Jaya, Wandammen, Wasior, DMP, 7.-10.I.2001, Riedel, MB 51", “51” [green label] (ZSM). 1 male "Indonesia: Irian Jaya, Wandammen, Wasior, DMP, 7.-10.I.2001, Riedel, "MB 52", “52” [green label] (ZSM).

Description.

Body size and form: Beetle small, with oblong-oval habitus (Figs 24 , 25 ).

Measurements: TL 4.9-5.6 mm, TL-H 4.5-5.2 mm, MW 2.4-2.8 mm, TL/MW 2-2.04; PL 0.7-0.8 mm, PW 2.1-2.4 mm, PL/PW 0.33-0.35; DBE 0.9-1 mm, DBE/PW 0.41-0.43.

Holotype: TL 5.5 mm, TL-H 5 mm, MW 2.75 mm, TL/MW 2; PL 0.8 mm, PW 2.3 mm, PL/PW 0.35; DBE 0.95 mm, DBE/PW 0.41.

Colouration: Dorsally brown to piceous, with reddish yellow to reddish brown head, pronotum or pronotal sides, and notched basal band, one narrow dorsal band and apical spot on elytron (Figs 24 , 25 ).

Head reddish yellow to reddish brown, darker narrowly behind eyes. Pronotum reddish yellow to reddish brown, with darker disc and paler sides; sometimes darkest parts just along middle of anterior and posterior margins. Elytron brown to piceous, with reddish yellow to reddish brown basal band of different length but not reaching suture and lateral elytral margin; its anterior margin reaching elytron basally and its posterior margin strongly notched: with two prolongation between puncture rows, sometimes with vague basal spot near suture; elytron with distinct, elongate apical spot and usually with narrow dorsal band slightly in front of second puncture row starting near basal band and of different length (maximum till slightly behind elytral length); elytron without lateral band. Scutellum usually reddish brown to piceous. Antennae and other head appendages yellow. Legs reddish yellow proximally and darker distally, especially metalegs. Venter mostly reddish yellow, with paler prosternum. Teneral beetles paler.

Surface sculpture: Elytron without striae, but with distinct puncture lines, or with 3-9 more or less complete dorsal striae, submarginal stria absent: (0-9)+0 (Figs 24 , 25 ).

Head without strioles, with relatively sparse, inconspicuous punctation (spaces between punctures 1-4 × size of punctures); punctures relatively small, weakly impressed (diameter of punctures slightly smaller than diameter of cells of microreticulation); head with a row of coarse setigerous punctures along inner margin of each eye and a short, weak row at frontal angle of each eye; a slightly longer puncture row forms fronto-clypeal depression at each head side; microreticulation strongly impressed. Pronotum with strioles only in females; with thin, longitudinal wrinkles at posterior margin; pronotal punctation finer than on head; coarse setigerous punctures form a broad row along pronotal margins, absent in posterior middle; disc of pronotum with thin, longitudinal median scratch. Pronotal microreticulation rather weakly impressed on disc. Pronotum often with fine strioles in females. Elytron without elytral striae but with two distinct puncture lines on disc and one less distinct laterally; two additional lines of very sparse, coarse setigerous punctures can be seen between elytral lines; or with 3-9 more or less complete dorsal striae, usually missing near suture and getting denser towards lateral margin. Elytron with very fine, inconspicuous punctation and weak microreticulation. Elytron often with fine 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 short, not numerous 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 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 broad, convex in middle.

Male: Protibia straight, not modified. Proclaws long; anterior claw shorter, thicker anteriorly (almost denticulate) and more strongly curved downwards than posterior due to median incision of its inner margin. Median lobe of aedeagus with two lobes of dorsal sclerite rather narrow; right dorsal lobe slightly longer than left one; in lateral view, apex of left dorsal lobe more or less straight, with longitudinal crest, deep incision and below it, concavity in lateral margin; right dorsal lobe with weakly developed, inconspicuous median impression (in right lateral view) and rounded apex. Left lobe of ventral sclerite with its sclerotised area large, very strongly sclerotised, distinctly shorter than right ventral lobe; its apex bilobed: left part short, broad, and rounded, right one long, thin, hooked; this sclerotised area hidden under right ventral lobe and between left and right lobes of dorsal sclerite, usually almost invisible (only hook’s apex can be visible) in left lateral view. Paramere with setae distinctly divided into distal and proximal; proximal setae distinctly sparser and slightly shorter than distal (Fig. 28 ).

Female: With pronotal strioles usually occupying entire lateral sides, and often presence of numerous but weak elytral strioles. Most of the females have strioles on elytra and pronotum but they are not very dense and not strongly impressed; therefore, dorsal surface is not matt, rather shiny.

Variability.

The species demonstrates insignificant variation in its dorsal colouration. It is so far known from two regions: Nabire and Wasior (Wandammen) and shows a distinct separation for them in the elytral striolation: specimens from Nabire without elytral striae and those from Wasior with them. Additionally, Wasior males have slightly differently shaped left lobe of the dorsal sclerite of the median lobe. However, this structure seems to be slightly variable within and among the populations. Therefore, more material is needed from Wandammen to continue study on the taxonomic status of its populations.

Affinities.

In absence of the elytral striae and general shape of the median lobe, it is most similar and most likely closely related to A. oksibilensis sp. nov. and A. brazza sp. nov.; see the comparison under these species. The new species co-occurs with A. febrisauri sp. nov., to which is very similar in size, colouration and surface structures but differs by more notched basal elytral band and presence of dorsal elytral band. Males can be also distinguished by lateral incision on the left lobe of the dorsal sclerite of the median lobe, as well as modified anterior claw; females by the presence of elytral strioles.

Etymology.

The species is named for its morphological similarity and close relationship to A. oksibilensis sp. nov. The name is a noun in the nominative standing in apposition.

Distribution.

New Guinean endemic. Indonesia: Papua Province: Nabire Regency and West Papua Province: Teluk Wondama Regency (Fig. 82 ).

Habitat.

At the type locality, the species was collected in a small forest pool (Fig. 87 ). At the track Nabire-Ilaga, all specimens were collected in shallow (up to 20 cm water depth), shaded or at least partly shaded forest pools and puddles of different size, rich in rotten leaves and twigs; few specimens also found in water-filled track hollows on forest tracks.

Figures

Figure 28. Austrelatus pseudooksibilensis 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 22 - 25. Habitus and colouration of 22 Austrelatus febrisauri sp. nov. 23 A. oksibilensis sp. nov. 24 A. pseudooksibilensis sp. nov., without elytral striae 25 A. pseudooksibilensis sp. nov., with elytral striae.

Figures 87, 88. Habitats of Austrelatus species 87 small forest pool at track Nabire-Ilaga, Km 62: type localities of A. innominatus sp. nov. and A. pseudooksibilensis sp. nov. and habitats of A. febrisauri sp. nov., A. rugosus sp. nov., and A. kaszabi (Guignot, 1956) 88 partly shaded rest pool of an intermittent stream at the road Wanggar to Bali Bumi: type locality of A. wanggarensis sp. nov. Photographs by LH.