Gibbidessus pictipes (Lea, 1899) Hendrich & Watts & Balke, 2020

Hendrich, Lars, Watts, Chris H. S. & Balke, Michael, 2020, The " minute diving beetles " of southern Australia - taxonomic revision of Gibbidessus Watts, 1978, with description of six new species (Coleoptera, Dytiscidae, Bidessini), ZooKeys 975, pp. 11-49 : 11

publication ID	https://dx.doi.org/10.3897/zookeys.975.55456
publication LSID	lsid:zoobank.org:pub:785EDF22-5A32-4217-8C9B-6433E0AD199F
persistent identifier	https://treatment.plazi.org/id/D81AB87E-52C7-5080-ACCE-2FF14EE8C4C8
treatment provided by	ZooKeys by Pensoft
scientific name	Gibbidessus pictipes (Lea, 1899)
status	comb. nov.

Treatment

Gibbidessus pictipes (Lea, 1899) View in CoL comb. nov. Figs 8 View Figures 8–11 , 9 View Figures 8–11 , 13 View Figure 13 , 20 View Figures 20, 21 , 30 View Figure 30 , 31 View Figure 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); Biström (1988: 10, systematics); Hendrich (2001a: 302, faunistics, habitat); Hendrich (2001b: 21, faunistics, habitat); Watts (2002: 31, 44, identification key, checklist); Nilsson & Hájek (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 View Figures 8–11 ).

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.

Head: Dark brown to ferruginous, without cervical line but rather a few punctures instead (punctures not obvious in females) (Fig. 13A View Figure 13 ). 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.

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.

Elytra: Dark brown with vague basal area ferruginous (Fig. 8 View Figures 8–11 ). Coarsely and densely punctate, shiny, microsculpture absent. Striae weakly impressed, slightly straighter than in female specimens and of same length as basal pronotal striae.

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.

Male. Dorsal surface with coarse punctures but otherwise with shiny surface (Fig. 8 View Figures 8–11 ). Median lobe of aedeagus as in Fig. 20A, B View Figures 20, 21 . 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 View Figures 20, 21 ).

Female. Dorsal surface almost mat, with coarse punctures and dense microreticulation (Fig. 9 View Figures 8–11 ).

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 View Figures 18, 19 , 20 View Figures 20, 21 , 21 View Figures 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 View Figures 24, 25 ).

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 View Figure 30 , 31 View Figure 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 View Figure 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 View Figure 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).