A review of Copelatus diving beetles from the Solomon Islands, reporting the discovery of six new species (Coleoptera, Dytiscidae, Copelatinae) Author Hajek, Jiri https://orcid.org/0000-0001-5779-1542 Department of Entomology, National Museum, Cirkusova 1740, CZ- 193 00, Prague 9 - Horni Pocernice, Czech Republic jiri.hajek@nm.cz Author Shaverdo, Helena Naturhistorisches Museum Wien, Burgring 7, 1010, Vienna, Austria Author Hendrich, Lars SNSB-Zoologische Staatssammlung Muenchen, Muenchhausenstrasse 21, D- 81247, Munich, Germany Author Balke, Michael https://orcid.org/0000-0002-3773-6586 SNSB-Zoologische Staatssammlung Muenchen, Muenchhausenstrasse 21, D- 81247, Munich, Germany & GeoBioCenter, Ludwig-Maximilians-University, Munich, Germany text ZooKeys 2021 2021-03-10 1023 81 118 http://dx.doi.org/10.3897/zookeys.1023.61478 journal article http://dx.doi.org/10.3897/zookeys.1023.61478 1313-2970-1023-81 F14F12AC47824643929A49941E24BB92 8E4EE48C84345AC48B877220002D94B6 Copelatus tulagicus Guignot, 1942 Figures 7 , 8 , 20 Copelatus apicalis J. Balfour-Browne , 1939: 78 ( type locality: " Solomon Islands : Tulagi ; preoccupied by Copelatus apicalis Fairmaire , 1898: 465 [currently in genus Madaglymbus Shaverdo & Balke , 2008]) . Copelatus tulagicus Guignot, 1942: 86 (as a replacement name for Copelatus apicalis J. Balfour-Browne, 1939: 78). Type material. Holotype : ♂ , labelled: "Type [round label with red frame, p] // 1826 [hw] // SOLOMON IS. [p] / Tulagi / 3.viii.1934 / on leaf. [hw] / R.A.Lever [p] // Pres.by / Imp.Inst.Ent. / B.M. 1936-90 . [p] // Copelatus / Copelatus apicalis , / ♂ Type sp. nov. / J.Balfour-Browne [hw]" ( NHMUK ) . Paratype : ♀ , labelled: "Type [round label with red frame, p] // PAPUA: Kokoda [yellow underlined] / I, 200ft. v.1933 . / L.E.Cheesman. / B.M.1933-577. [p] // Copelatus / Copelatus apicalis , / ♀ Type sp. nov. / J.Balfour-Browne [hw]" ( NHMUK ) . Additional material examined. Guadalcanal : 1 ♀ , Kukum , 28.iii.1958 , E.S. Brown leg. ; 1 ♂ , 1 ♀ , Kukum , 20.v.1963 , P. Greenslade leg. ; 1 ♀ , same data, but 29.v.1963 ; 3 ♀♀ , same data, but 8.i.1965 ; 1 ♀ , same data, but 26.v.1962 ; 1 ♂ , Mt. Austen , xii.1965 - i.1966 , P. Greenslade leg. (all NHMUK ) ; 1 ♂ , ca 4.5 km S of Barana vill., forest near "Japanese camp" at Moka river , 09°30.3'S , 159°58.9'E ; 275 m , 5.-6.xii.2013 , J. Hajek leg. ; 1 ♀ , Mt. Austine , Barana vill. env., 09°28.0'S , 159°58.4'E , 280 m , 23.xi.-8.xii.2013 , J. Hajek leg. (all NMPC ) . Santa Isabel : 1 ♀ , Ysabel , Gatere , 19.ii.1956 , E.S. Brown leg. ( NHMUK ). Diagnosis. Medium sized (TL: 5.8-6.8 mm ), elongate, oblong-oval species. Elytra with transverse testaceous basal band, which does not reach either suture or lateral margin, and with relatively small apical testaceous spot (Figs 7 , 8 ). Pronotum with short longitudinal strioles near posterior angles. Elytra with six well impressed discal striae and a submarginal stria: striae 1 and 5 beginning more posteriorly than other striae; submarginal stria long, beginning at elytral mid length. Female dimorphic; striolate form with dorsal surface matt and with coarse microreticulation and numerous strioles on pronotum and elytra, except for apex (Fig. 8 ). Median lobe hook-like shaped in lateral view, simple; broadened and with distinct pit in two thirds of its length, apically tapering and strongly curved dorsally (Fig. 20A-C ). Parameres "D" -shaped; apical lobes moderately long (Fig. 20D ). Figures 7, 8. Habitus of Copelatus 7 C. tulagicus Guignot, 1942 ( holotype ; TL: 6.5 mm ) 8 C. tulagicus (striolate female, Guadalcanal ; TL: 6.1 mm ). Comments on classification. Based on the characteristic hook-like shape of the median lobe, C. tulagicus apparently belongs to a complex of species distributed in Sunda Islands and New Guinea , including C. geniculatus Sharp, 1882, C. gentilis Sharp, 1882, C. lineatus ( Guerin-Meneville , 1838), C. biroi Guignot, 1956, and C. subterraneus Gueorguiev , 1978 (of the C. irinus species group) and several additional undescribed species; the most closely related species is probably C. martinbaehri Hendrich et al., 2019 described recently from southeastern PNG and northern Queensland. Copelatus tulagicus was described based on a male from Solomons and female specimen from southeastern New Guinea (Kokoda). The conspecificity of the female with the male holotype is doubtful with the respect to recently described C. martinbaehri from Central Province ( Papua New Guinea ), which differs from C. tulagicus only in the shorter and straighter apical part of the male median lobe of the aedeagus . Distribution. The species seems to be widely distributed across the New Guinea and the Solomon Islands . Habitat. The specimen from Barana was recently collected together with C. portior in a streamlet flowing through secondary forest and gardens near the village (Fig. 26 ). The specimen from Moka River was collected in a small puddle near the river. Some specimens from Kukum were covered with moth scales and they were apparently collected at light.