Austrelatus, 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

Austrelatus gen. nov.

Type species.

Copelatus irregularis W.J. Macleay, 1871: 126, by present designation.

Material studied.

Copelatus badeni Sharp, 1882: 1 male "Taveuni. Fiji. (Viti Levu) Sylvester Evans" [hw], " Fiji. Dr. H.S. Evans " [hw], " Copelatus Badeni [hw] det. A. Zimmermann [pr]" (BMNH) .

Copelatus boukali Hendrich & Balke, 1998: Holotype: male "S-Indien: Kerala (7), 15 km SW Munnar Kallar Valley 76°68'E 10°02'N ", " 1000 m 6.- 18.12.1993 leg. Boukal & Kejval" (NHMW).

Copelatus davidi Wewalka, 2017: Holotype: male " India: Kerala, 1.1.1999 30 km NNE Trivandrum, 400 m Kallar Bridge , 08°45'N 77°05'E leg. D. Boukal (35)" (NHMW).

Copelatus fidschiensis Zimmermann, 1928: Syntypes: 1 male “Type”, [round label with red frame], "C81 Suva 25-3-27" [hw], " Fiji Islands. H.W. Simmonds. ", "Pres. by Imp. Bur. Ent. Brit. Mus. 1972-355", " Copelatus fidschiensis Type. Zimerm. [hw] det. A. Zimmermann [pr]" (BMNH) . 1 male “Co-type”, [round label with yellow frame], "C81 Suva 25-3-27" [hw], " Fiji Islands. [pr] R.W. Faime [hw]", "Pres. by Imp. Bur. Ent. Brit. Mus. 1972-355", " Copelatus fidschiensis , ♂ Zim. Cotype." [hw] (BMNH) .

Copelatus gestroi Régimbart, 1892: Lectotype (by present designation for nomenclatural stability): male "N. GUINEA MER. RIGO Luglio 1889 L.Loria ", "Neu Guinea Mus. Genua", " Copelatus Gestroi Reg." [hw], " Coll. Mus. Vindob. ", " Lectotype Copelatus gestroi Régimbart, 1892 des. H. Shaverdo 2023" [red] (NHMW) . Paralectotypes (with red labels): 2 males, 6 females "N. GUINEA MER. RIGO Luglio 1889 L.Loria ", " Neu Guinea Mus. Genua " (NHMW) . 1 male "N. GUINEA MER. RIGO Luglio 1889 L.Loria ", "Neu Guinea Mus. Genua ", " Copelatus Gestroi Reg. " [hw] (NHMW) . 1 male "N. Guinea Rigo Luglio 1889 L.Loria " [hw], " Neu Guinea Mus. Genua " (NHMW) . 2 males "N. GUINEA MER. RIGO Luglio 1889 L.Loria ", “Cotype” [red], " Regimbart det., 1891: Copelatus (s. str.) Gestroi - Reg. " [partly hw] (ZSM) . 2 males "N. GUINEA MER. RIGO Luglio 1889 L.Loria ", "Neu Guinea 7407" [partly hw], " Copelatus Gestroi Rg det. Gschwendt." [hw], " Staatl. Museum für Tierkunde, Dresden " (MTD) . 2 females "N. GUINEA MER. RIGO Luglio 1889 L.Loria ", "Neu Guinea 7407" [partly hw], " Staatl. Museum für Tierkunde, Dresden " (MTD) . 3 males, 2 females "N. GUINEA MER. RIGO Luglio 1889 L.Loria ", "Neu Guinea 8947" [partly hw], " Staatl. Museum für Tierkunde, Dresden " (MTD) .

Copelatus luteomaculatus Guignot, 1956: Holotype: male "N. Guinea Biró 97.", "Stephansort Astrolabe B", " Holotypus 1956 ♂ Copelatus luteomaculatus Guignot" [label with red frame, partly hw by Guignot], “Type” [red label], " Dr F. Guignot det., 1955 Copelatus luteomaculatus sp.n. HoloType ♂ " [partly hw by Guignot] (HNHM) . Paratypes: 2 females "N. Guinea Biró 1898", "Simbang Huon Golf // IX.17. [hw on reverse side]", " Paratypus 1956 Copelatus luteomaculatus Guignot" [label with red frame, partly hw by Guignot ] (HNHM) .

Copelatus papuensis J. Balfour-Browne, 1939: Holotype: male “♂” [hw, next to beetle], “Type” [round label with red frame], " PAPUA: Kokoda. 1,200ft. v.1933. L.E. Cheesman. B.M.1933-577. // 57 [hw on reverse side]", " Copelatus papuensis , B-B. ♂ TYPE" [hw by J. Balfour-Browne], "Manuscript name" [printed in red] , “Holotype”.

Copelatus strigosulus Fairmaire, 1878: 1 male “♂”, “am3” [hw], " Fiji. Viti Levu near Suva Dr M. Larcb [?] 22.II.53" [hw], "put-hole stream edge" [hw], " Copelatus strigulosus Fairm [hw] C.M.F. von Hayek det., 1954 [pr]", "Brit. Mus. 1987-14" (BMNH) .

Copelatus ternatensis Régimbart, 1899: Syntypes: 1 male " Ternate X [hw] Beccari 187 [pr] 5 [hw]", "C. sp. 2882." [yellow label, hw], " Copelatus sp. [hw] det. Régimbart [pr]", " SYNTYPUS [pr] Copelatus ternatensis Régimbart, 1899 [hw]" [red label], " Museo Civico di Genoa " [pr] (MSNG) ; 3 males " Ternate X [hw] Beccari 187 [pr] 5 [hw]", " Copelatus sp. [hw] det. Régimbart [pr]", " SYNTYPUS [pr] Copelatus ternatensis Régimbart, 1899 [hw]" [red label], " Museo Civico di Genoa " [pr] (MSNG) .

Copelatus wallacei J. Balfour-Browne, 1939: 3 males, 5 females " INDONESIA, N Moluccas, Bacan Isl. , 500-750 m, SE slopes of Mt. Sibela, 5 km SE of Makian vill., S. Jákl leg., 2.-12.V.2008 " (NMPC) .

Copelatus xanthocephalus Régimbart, 1899: Lectotype (by present designation for nomenclatural stability): male [small, red, square label], "2795 78" [round label, hw], "Nolle [illegible, probably short form from Nouvelle] Guinée” [hw], "MUSEUM PARIS COLL. MAURICE REGIMBART 1908", “Muséum Paris Nouvelle-Guinée (Amberbaki) A. Raffray 1878", “SYNTYPE” [red], " SYNTYPE Copelatus xanthocephalus Régimbart, 1899", " MNHN, Paris EC14220 [barcode]", " Lectotype Copelatus xanthocephalus Régimbart, 1899 des. H. Shaverdo 2023" [red] (MNHN) . Paralectotype: 1 female "2795 78" [round label, hw], "Nolle [illegible, probably short form from Nouvelle] Guinée Raffray" [hw], "MUSEUM PARIS COLL. MAURICE REGIMBART 1908", " Copelatus xanthocephalus Rég” [hw], “Muséum Paris Nouvelle-Guinée (Amberbaki) A. Raffray 1878", “SYNTYPE” [red], " SYNTYPE Copelatus xanthocephalus Régimbart, 1899", " MNHN, Paris EC14219 [barcode]", " Paralectotype Copelatus xanthocephalus Régimbart, 1899 des. H. Shaverdo 2023" [red] (MNHN) .

Additionally, please see the material of the species (re)described below.

Diagnosis.

Elytra with or without striae; metacoxal lines present but incomplete, absent close to metaventrite; male protarsomere 4 simple, with not modified (thin) anterolateral seta; median lobe of aedeagus complex, with evident dorsal and ventral sclerites usually divided in apical half into two lobes of different shape or otherwise modified; paramere simple, of narrow triangular form, with thin apex and numerous setae; male pro- and mesotarsomeres 1-3 dilated, with ca. 40-55 small stalked adhesive discs in five or six rows, larger discs can be present in second and third rows, two or three in each; female metatibia and metatarsus with dorsal and ventral rows of natatorial setae.

Austrelatus gen. nov. can be distinguished from all other genera of Copelatinae by the above combination of characters. From the most species of two co-occurring Australasian genera, Exocelina and Copelatus , representatives of the new genus differ by the median lobe of the aedeagus distinctly divided into dorsal and ventral sclerites, which are usually well-developed and differently modified; from Exocelina , additionally by anterolateral seta of the male protarsomere 4 thin, not modified into a hook; see also the generic description of the male genitalia, key to Copelatinae of New Guinea and illustrations below.

Description.

Body size and form: Beetles small to large, TL ca. 4-9 mm, with usually oblong-oval, more seldom oval or elongate, almost sub-parallel habitus, distinctly convex in lateral view; body outline continuous, without discontinuity between bases of pronotum and elytra.

Colouration: Beetles reddish to piceous, usually with paler head and pronotal sides, and often with paler, to yellowish, basal band or spot(s) and apical spot on elytron.

Surface sculpture: Elytron usually with up to 11 dorsal striae or sometimes without them; submarginal stria present or absent: (0-11)+(0-1). Head, pronotum and elytron sometimes with strioles. Dorsal and ventral surface with fine punctation and microreticulation.

Structures: Head with anterior margin of clypeus slightly and evenly concave, with distinct bead laterally on both sides. Pronotum broadest at posterior angles; lateral margins slightly to distinctly convergent anteriorly, posterior angles slightly rounded. Pronotal base as broad as base of elytra. Pronotum with thin lateral bead missing at anterior angles. Elytron with distinct lateral bead weakening at apex. Base of prosternum narrowly to broadly rounded anteriorly, convex medially; neck of prosternal process convex; neck and blade of prosternal process evenly joined; blade of prosternal process lanceolate, with distinct lateral bead laterally and broadly pointed apex. Lateral parts of metaventrite tongue-shaped, very slender. Metacoxal lines divergent, sometimes only slightly, distinct, or indistinct close to metaventrite, not reaching it. Abdominal ventrite 6 beaded, broadly rounded, seldom slightly truncate.

Male: Antenna simple, with antennomeres long and slender. Protibia usually simple, i.e., with roughly triangular outline; more seldom, modified: thinner proximally, broader medially and distally due to its curved ventral margin. Pro- and mesotarsomeres 1-3 distinctly broadened, with adhesive discs on their ventral side. Protarsomere 4 small, with several long, thin setae. Protarsomere 5 long, thin, with small, sometimes inconspicuous setae medially. Proclaws relatively long and equal; more seldom, anterior claw shorter, modified.

Median lobe of aedeagus with well-developed dorsal and ventral sclerites of different shape, modification, and degree of sclerotisation: in species from west of Wallace Line (India and Greater Sunda), apex of median lobe usually pointed in ventral view, ventral sclerite much shorter than dorsal one, sclerites apically not divided into two lobes; in species from east of Wallace Line, dorsal and ventral sclerites subequally developed, apex of each sclerites usually divided apically into two distinct lobes. Paramere simple, of triangular form, rarely elongate and often broad basally, either continuously or abruptly narrowing to slender apical part (sometimes paramere subdivided with less sclerotised area to broad basal and narrow apical parts); with dense long setae in apical half of dorsal margin; in some species, paramere setae can be divided by a median or submedian part with few sparse setae into distal and proximal setae; distal setae more numerous, denser, and usually longer than proximal ones; especially in left paramere of some species, proximal setae less numerous and sparse.

Female: Similar to males in external morphology, except for not modified protibial, pro- and mesotarsi, and proclaws. Most of the females have more intensive dorsal surface sculpture, e.g., sometimes with numerous thin, longitudinal strioles on elytra and pronotum that densely cover dorsal surface and make it matt; dimorphic females are known in one species from the Solomon Islands and several New Guinean species. Metatibia and metatarsus with dorsal and ventral rows of natatorial setae.

Molecular study.

The species characterised by the above-mentioned morphological characters were all retrieved in one clade, which is the sister to all other analysed Copelatus . To highlight this dichotomy, we also decided to propose a new genus name for all these species.

Etymology.

The name of the new genus Austrelatus combines the Latin part Austr - (southern) and Greek part - elatus (from elaunein, to row) and means "southern rower". It has also been chosen to indicate that its type species and most of its known representatives, including the former Copelatus species, occur in and are even endemic to the Australian Region.

Distribution and species composition.

The new genus is mainly known from the Australian Region (Australia, New Guinea, Fiji, Solomon Islands, Maluku Island), with several species penetrating the Wallace Line into the Oriental and SE Palaearctic regions (Greater and Lesser Sunda Islands, India, SE China, and Japan); currently, no Austrelatus is known from continental SE Asia.

In Australia, Austrelatus is represented by six species with rather distinct morphology; only A. irregularis and A. daemeli can be grouped together based on similarity of their male genitalia.

Nine species of Austrelatus have so far been known from New Guinea. However, the genus comprises more than 60 different species there, most of which can be grouped in two large species groups: the A. papuensis group (ca. 40 species, including A. gestroi , A. luteomaculatus , A. papuensis , and A. xanthocephalus partly treated here), which will be defined in detail (Shaverdo et al., unpublished data), and the A. neoguineensis group introduced here with three previously known and 29 new species. Austrelatus setiphallus sp. nov. and A. fumato sp. nov. are very similar to the representatives of the A. neoguineensis group according to our unpublished molecular phylogenetic analysis but shows rather special morphology of the median lobe and parameres; therefore, they are treated separately.

From ten known Copelatinae species of Solomon Islands, Austrelatus gen. nov. is represented by six species in two species groups: A. laevipennis , A. variistriatus , and A. urceolus most likely form an inherent group presumably endemic to Solomons. Austrelatus baranensis , A. bougainvillensis , and A. kietensis belong to the above-mentioned A. papuensis group.

All Fijian copelatine species belong to Austrelatus gen. nov. They form a monophyletic group again based on our unpublished molecular phylogenetic analysis, and are very similar morphologically. However, only five species have been described so far; more than 25 species have already been delineated based on molecular methods and morphology ( Monaghan et al. 2006; Shaverdo et al., unpublished data).

Four species of the new genus are known from the Indonesian Archipelago. Austrelatus uludanuensis from Bali is morphologically different from other species, probably representing a well delineated clade. The Moluccan species A. sibelaemontis , A. ternatensis and A. wallacei most likely belong to the A. papuensis group. Several additional undescribed Austrelatus species are known to us across the Indonesian Archipelago, from Sumatra and Kalimantan to Flores, Ceram, and Kai ( Hájek et al., unpublished data).

The Oriental and SE Palaearctic representatives of the new genus are five species from India, which all have a characteristic structure of the male genitalia, and A. parallelus from Japan and China. They build a rather interesting complex outside the Australasian species.

At present, 62 Austrelatus species are known, including the new, described here New Guinean species (Table 1 ).