The " minute diving beetles " of southern Australia - taxonomic revision of Gibbidessus Watts, 1978, with description of six new species (Coleoptera, Dytiscidae, Bidessini) Author Hendrich, Lars SNSB - Zoologische Staatssammlung Muenchen, Muenchhausenstrasse 21, D - 81247 Muenchen, Germany https://orcid.org/0000-0001-8366-0749 hendrich1@aol.com Author Watts, Chris H. S. South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia Author Balke, Michael SNSB - Zoologische Staatssammlung Muenchen, Muenchhausenstrasse 21, D - 81247 Muenchen, Germany https://orcid.org/0000-0002-3773-6586 text ZooKeys 2020 975 11 49 http://dx.doi.org/10.3897/zookeys.975.55456 journal article http://dx.doi.org/10.3897/zookeys.975.55456 1313-2970-975-11 785EDF225A3242178C9B6433E0AD199F FE5DCB656614590DB4C35092D89F3F3D Gibbidessus pictipes (Lea, 1899) comb. nov. Figs 8 , 9 , 13 , 20 , 30 , 31 Bidessus pictipes Lea, 1899: 523 (original description). Uvarus pictipes (Lea, 1899): Watts (1978 : 33, comb. nov., redescription); Watts (1985 : 24, checklist); Lawrence et al. (1987 : 335, catalogue); Bistroem (1988 : 10, systematics); Hendrich (2001a : 302, faunistics, habitat); Hendrich (2001b : 21, faunistics, habitat); Watts (2002 : 31, 44, identification key, checklist); Nilsson & Hajek (2020: 128, catalogue). Type locality. Australia, south-western Australia, Pinjarrah [ 32°37'56S , 115°51'49E ]. Type material. Syntype , female, "pictipes Lea Type Pinjarrah" (handwritten label), " Bidessus pictipes Lea W. Australia TYPE" (handwritten label), " SAMA Database No 25-001599" (SAMA). Additional material studied (320 exs.) . 51 exs., "WA Lake Nalyerin 33 08S, 116 22E CHS, Watts 6/10/03", " SAMA Database 25-009282" (SAMA); 4 exs., "Nalyeen Lake [Nalyerin] WA J. McRae 8/10/97", " SAMA Database No 25-002918" (SAMA); 1 ex., "WA Byenup Lagoon NR 21/9/00 C.H.S. Watts" " SAMA Database No 25-002922" (SAMA). 2 exs., "Australia, WA, SWA31 (A), Helena River, 22/08/2005, South-west Forest Monitoring" (DPAW); 1 ex., "Australia, WA, HAR21 (A), Stirling Dam 2, 7/09/2006, South-west Forest Monitoring" (DPAW); 3 exs., "Australia, WA, SPM011 (B) Kulicup Swamp, 6/11/1998, Salinity Action Plan Wetland Monitoring Programme" (DPAW); 1 ex., "Australia, WA, SPM011 (A) Kulicup Swamp [ 34°20'1S , 116°47'17E ], 23/10/2002, Salinity Action Plan Wetland Monitoring Programme" (DPAW); 1 ex., "Australia, WA, SPM011 (B) Kulicup Swamp [ 34°20'1S , 116°47'17E ], 23/10/2002, Salinity Action Plan Wetland Monitoring Programme" (DPAW); 2 exs., "Australia, WA, SPM011 (A) Kulicup Swamp [ 34°20'1S , 116°47'17E ], 11/10/2000, Salinity Action Plan Wetland Monitoring Programme" (DPAW); 2 exs., "Australia, WA, SPM011 (B) Kulicup Swamp [ 34°20'1S , 116°47'17E ], 11/10/2000, Salinity Action Plan Wetland Monitoring Programme" (DPAW); 1 ex., "Australia, WA, SPM024 (A) Lake Pleasant View [ 34°49'S , 118°10'E ], 24/10/1999, Salinity Action Plan Wetland Monitoring Programme" (DPAW); 3 exs., "Australia, WA, SPM024 (A) Lake Pleasant View [ 34°49'S , 118°10'E ], 24/10/2003, Salinity Action Plan Wetland Monitoring Programme" (DPAW); 2 ex., "Australia, WA, SPM024 (B) Lake Pleasant View [ 34°49'S , 118°10'E ], 24/10/2001, Salinity Action Plan Wetland Monitoring Programme" (DPAW); 4 exs., "Australia, WA, SPM024 (A) Lake Pleasant View [ 34°49'S , 118°10'E ], 24/10/1999, Salinity Action Plan Wetland Monitoring Programme" (DPAW); 1 ex., "Australia, WA, RUAB01 (A) Ruabon Road 01 [ 33°37'S , 115°27'E ], 11/10/2007, South-west Catchment Council Wetland monitoring" (DPAW); 1 ex., "Australia, WA, RVDLE03 (A) Riverdale 03 [ 32°59S , 115°47E ], 4/10/2007, South-west Catchment Council Wetland monitoring" (DPAW); 30 exs., "Australia, WA, SPS111 (A), Boyacup Bridge Swamp [ 34°13'S , 117°15'E ], 10/10/1998, Salinity Action Plan Wetland Biological Survey" (DPAW); 1 ex., "Australia, WA, SPS032 (A), Qualeup Lake [ 33°50'S , 116°45'E ], 9/10/1998, Salinity Action Plan Wetland Biological Survey" (DPAW); 2 exs., "Australia, WA, SPS103 (A), Lake Poorginup [ 34°32'S , 116°44'E ], 2/10/1998, Salinity Action Plan Wetland Biological Survey" (DPAW); 4 exs., "Australia, WA, SPS104 (A), Pindicup Lake [ 34°25'S , 116°43'E ], 2/10/1998, Salinity Action Plan Wetland Biological Survey", one specimen "M. Balke DNA 7250" [green printed label] (DPAW, ZSM); 1 ex., "Australia, WA, MUB030 (A), Pindicup Lake [ 34°25'S , 116°43'E ], 25.09.2014, Muir-Byenup Survey" (DPAW); 11 exs., "Australia, WA, MUB030 (A), Pindicup Lake, 25.09.2014, Muir-Byenup Survey (DPAW); 4 exs., "Australia, WA, SPS105 (A) Kodjinup Melaleuca Swamp [ 34°23'S , 116°39'E ], 2/10/1998, Salinity Action Plan Wetland Biological Survey" (DPAW); 30 exs, "Australia, WA, SPS108 (A) Pillenorup Swamp, 30/09/1998, Salinity Action Plan Wetland Biological Survey" (DPAW); 7 exs., "Australia, WA, SPS113 (A) Tucker's Road Melaleuca Swamp, 27/08/1998, Salinity Action Plan Wetland Biological Survey" (DPAW); 1 ex., "Australia, WA, LVR003 (A) Lower Vasse River Site 3, 4/10/2001, Lower Vasse River Clean-up Program" (DPAW); 1 ex., "Australia, WA, LVR004 (A), Lower Vasse River Site 4, 5/10/2001, Lower Vasse River Clean-up Program" (DPAW); 1 ex., "Australia, WA, LVR005 (A), Lower Vasse River Site 5, 5/10/2001, Lower Vasse River Clean-up Program" (DPAW); 6 exs., "Australia, WA, JCS019 (A), Sedge Swamp W of Deadhorse Soak [ 29°54'7S , 115°1'11E ], 21/09/2011, Jurien Coastal Survey" (DPAW); 1 ex., "Australia, WA, Mulgarnup MUB 012, 28.01.2004, Andrew Storey leg." (DPAW); 2 exs., "Australia, WA, Mulgarnup MUB 012, 1.10.2014, M. Pennifold leg.", two specimens "M. Balke DNA 7252", "M. Balke DNA 7253" [green printed labels] (ZSM); 4 exs., "Australia, WA, W Kodjinup #18 [ 34°23'S , 116°39'E ], 28.01.2004, Andrew Storey leg." (DPAW); 1 ex., "Australia, WA, Wimbalup #52 [ 34°29'S , 116°50'E ], 29.11.2003, Andrew Storey leg." (DPAW); 11 exs., "Australia, WA, MUB019 (A), Galamup Swamp [ 34°26'S , 116°45'E ], 30.09.2014, Muir-Byenup Survey", one specimen "M. Balke DNA 7262" [green printed label] (DPAW, ZSM); 23 exs., "Australia, WA, MUB035, NE Unicup NR [ 34°20'S , 116°43'E ], 24.09.2014, Muir-Byenup Survey", one specimen "M. Balke DNA 7257" [green printed label] (DPAW, ZSM); 43 exs., "Australia, WA, MUB037 (A) S, Kulunilup NR [ 34°20'S , 116°47'E ], 25.09.2014, Muir-Byenup Survey", three specimens "M. Balke DNA 7259", "M. Balke DNA 7260", "M. Balke DNA 7261" [green printed labels] (DPAW, ZSM); 11 exs., "Australia, WA, MUB011 (A) Kulunilup Lake [ 34°20'S , 116°47'E ], 25.09.2014, Muir-Byenup Survey" (DPAW); 2 exs., "Australia, WA, MUB008 (B) Noobijup Swamp [ 34°23'S , 116°47'E ], 24.09.2014, Muir-Byenup Survey" two specimens "M.Balke DNA 7254", "M. Balke DNA 7255" [green printed labels] (DPAW, ZSM); 1 ex., "Australia, WA, MUB005 (A), Yarnup Swamp [ 34°22'26S , 116°52'4E ], 22.09.2014, Muir-Byenup Survey" (DPAW); 12 exs., "Australia, WA, MUB012 (A), Mulgarnup Swamp [ 34°15'1S , 116°41'44E ], 01.10.2014, Muir-Byenup Survey" (DPAW); 1 ex., "Australia, WA, Twin Swamps NW [ 31°43'7S , 116°0'50E ], 24/09/1992, Twin Swamps/Ellen Brook Survey" (DPAW); 1 ex., "Australia, WA, SPS031, 08/10/1997, SAP Survey" (DPAW); 1 ex., "Australia, WA, ABP041, 14/09/2007, Avon Baselining Project" (DPAW); 26 exs., "Australia, WA, Albany Hwy, Muir Lakes Nature Reserve, SW part of Byenup Lagoon, 4.& 5.1.2000, 34°29'S , 116°44'E , Hendrich leg. (loc. WA 11/157)" (CLH, ZSM); 18 ex., "Australia, WA, Albany, 3 km ENE Manypeaks, Lake Pleasant Nature Reserve, 7.1.2000, 34°49'S , 118°10'E , Hendrich leg. (loc. WA 13/159) (CLH, ZSM); 38 exs., "Australia, WA, Darling Range, Lane Poole Conservation Reserve, Nalyerin Lake, 300 m, 29. & 30.12.1999, 33°8.51'S , 116°22.15'E , Hendrich leg. (loc. WA 4/151)" (CGC, CLH, ZSM); 1 ex., "Australia: SW WA, 3 km NE Manypeaks, Lake Pleasant View NR, 91m, 2.I.2007, 34°49'S , 118°10'E , L. & E. Hendrich leg. (WA 160)" (ZSM). Note. Watts (1978) , who moved Bidessus pictipes to Uvarus , already noticed that this species might not belong to Uvarus : "It is with considerable hesitation that I place the following species in this genus. I suspect that it will eventually prove to belong to a genus of its own". Diagnosis. Small and dark brown species, with vague testaceous markings on elytra, and with habitus disruption between pronotum and elytron. Dorsoventrally rather flattened. Head without cervical line but rather a few punctures instead (punctures not obvious in females) (Fig. 8 ). Figures 8-11. Habitus of 8 G. pictipes , male 9 G. pictipes , female 10 G. rottnestensis sp. nov., male 11 G. rottnestensis sp. nov., female. Scale bar: 1.0 mm. Measurements : Lectotype, female: TL = 1.45 mm, TL-H = 1.25 mm, MW = 0.82 mm. Additional material: TL = 1.45-1.6 mm, TL-H = 1.3-1.4 mm, MW = 0.8-0.83 mm. Figure 12. Head of G. davidi sp. nov. A with cervical line (red arrow), and head of G. pederzanii sp. nov. B without cervical line but rather a few punctures instead (red arrow). Head : Dark brown to ferruginous, without cervical line but rather a few punctures instead (punctures not obvious in females) (Fig. 13A ). Evenly and coarsely punctate, shiny but with weak microreticulation. Punctures weakly anteriorly and strongly posteriorly between eyes. Antennae relatively short, stout. Antennomeres 1-3 ferruginous, 4-11 darkened anteriorly. Figure 13. Head of G. pictipes A without cervical line (red arrows), and of G. rottnestensis sp. nov. B without cervical line but rather a few punctures instead (red arrows). Pronotum : Ferruginous, anterior and posterior margins darker, broadest at middle. Punctation very weak, almost evenly distributed, shiny and microsculpture absent. Sides of pronotum margined and almost evenly rounded. Angle between pronotum and elytra well pronounced, basal pronotal plicae present. Striae moderately defined, almost 1/2 length of pronotum, strongly incurved. Figures 14, 15. 14 Gibbidessus atomus sp. nov. 15 G. chipi A median lobe in ventral view B median lobe in lateral view, left side C left paramere in lateral view. Scale bar: 0.2 mm. Elytra : Dark brown with vague basal area ferruginous (Fig. 8 ). Coarsely and densely punctate, shiny, microsculpture absent. Striae weakly impressed, slightly straighter than in female specimens and of same length as basal pronotal striae. Figures 16, 17. 16 Gibbidessus davidi sp. nov. 17 G. drikdrikensis sp. nov. A median lobe in ventral view B median lobe in lateral view, left side C left paramere in lateral view, D right paramere in lateral view. Scale bar: 0.2 mm. Ventral side : Ferruginous. Prothorax and apex of abdomen paler than other parts. Metacoxae and metaventrite covered with numerous larger punctures, surface shiny, without microreticulation. Abdominal ventrites with finer punctures, shiny, microreticulation absent. Metacoxal lines almost straight, anteriorly slightly divergent. Epipleuron ferruginous, coarsely punctate, shiny, lacking microsculpture. Legs ferruginous with meta-/mesotibia and meta-/mesotarsi somewhat darkened. Figures 18, 19. 18 Gibbidessus kangarooensis sp. nov. 19 G. pederzanii sp. nov. A median lobe in ventral view B median lobe in lateral view, left side C left paramere in lateral view D right paramere in lateral view. Scale bar: 0.2 mm. Male . Dorsal surface with coarse punctures but otherwise with shiny surface (Fig. 8 ). Median lobe of aedeagus as in Fig. 20A, B . Shape of median lobe, bent evenly and fairly uniform in lateral view, in ventral view tapering and pointed at apex. Parameres bi-segmented, elongated, and with setae inside apical hook (Fig. 20C, D ). Female . Dorsal surface almost mat, with coarse punctures and dense microreticulation (Fig. 9 ). Affinities. This species is similar to G. kangarooensis sp. nov. and the larger G. rottnestensis sp. nov. (TL = 1.5-1.7 mm) but readily separated by the different colour pattern. Furthermore, all three species can be separated by the form of their median lobes and parameres (Figs 18 , 20 , 21 ). Distribution. South-western Australia. The most common and widespread species in south-western Australia and a more inland species. South of a line from 230 km north of Perth (Leeman) to Albany (Fig. 24 ). Habitat. Permanent and seasonal, very shallow, sun exposed or half-shaded sedge swamps, lakeshores, larger ponds and flooded meadows on sandy bottom, with a thin layer of peat or rotten debris of sedges (Figs 30 , 31 ). A winter and early spring breeder. Most specimens were collected in September and October, with the next generation in December and January. Apart from G. pictipes , the water beetle coenosis at Nalyerin Lake (Fig. 31 ) included the following species: Dytiscidae : Limbodessus inornatus , Antiporus hollingsworthi , Sternopriscus minimus , Exocelina ater ; Hydrophilidae : Enochrus eyrensis , Limnoxenus zealandicus , Paracymus pygmaeus (see Hendrich 2001b ). At Manypeaks (Fig. 30 ) G. pictipes was collected with the Dytiscidae : Limbodessus inornatus , Sternopriscus browni Sharp, 1882, S. multimaculatus (Clark, 1862), S. storeyi Hendrich & Watts, 2004, S. wattsi Hendrich & Watts, 2004, Necterosoma darwinii (Babington, 1841), Rhantus suturalis and Lancetes lanceolatus (Clark, 1863).