Neobidessodes thoracicus Hendrich & Balke

HENDRICH, LARS, HAWLITSCHEK, OLIVER & BALKE, MICHAEL, 2009, The epigean Australasian species of Neobidessodes gen. n. diving beetles- a revision integrating morphology, cybertaxonomy, DNA taxonomy and phylogeny (Coleoptera: Dytiscidae, Bidessini), Zootaxa 2288 (1), pp. 1-41 : 25-32

Neobidessodes thoracicus Hendrich & Balke sp.n.

( Figs 9, 10, 11, 12 , 13, 14 , 26 , 28 , 30, 35 , 36, 37 )

Type locality. Cullen River [14.02.052S 131.56.561E], Northern Territory, Australia.

Type material. Holotype. Male : “ Australia: NT, Cullen River n. Cullen, at Stuart Hwy, 102m, 23.VIII.2006, 14.02.052S 131.56.561 E, L. & E. Hendrich leg. (NT 13)” “ Holotype Neobidessodes thoracicus sp. n. Hendrich & Balke des. 2009” [red printed label] ( SAMA).

Notes. In the following listing of the paratypes we present those specimens separately which have reduced yellowish pattern of the surface and, thus, in part are even almost black (see details under “Colour” in the description).

Paratypes (1866 specimens). Western Australia. 33 exs., “ AUSTRALIA /WA/Shire of Wyndham – East Kimberley , Great Northern Hwy 50 km S Wyndham, Black Flag Creek 50 m, 13.6.1999, Hendrich leg./ Loc. 4 /

104” ( CLH, SAMA, ZSM); 107 exs., “ AUSTRALIA /WA/ East Kimberley , Gibb River Road, Durack River Crossing, 250 m, 13.6.1999, Hendrich leg./coll./ Loc. 6/106” ( CLH, ZSM) ; 50 exs., “ AUSTRALIA /WA/ East Kimberley , Gibb River Road, Dawn Creek Crossing, 300 m, 13.+ 14.6.1999 Hendrich leg./coll. Loc. 7/107” ( CLH, SAMA, ZSM) ; 29 exs., “ AUSTRALIA /WA/ East Kimberley , Gibb Range , Gibb River Road, Russ Creek Crossing, 380 m, 14.6.1999, Hendrich leg./coll. loc. 8/108” ( CLH) ; 46 exs., “ AUSTRALIA /WA/ East Kimberley , Gibb River Road, Drysdale River Crossing, 380 m, 14.6.1999, Hendrich leg./coll./loc. 9/109” ( CLH) ; 16 exs., “ AUSTRALIA /WA/ East Kimberley , Gibb River Road, King Edward River Crossing, 280 m, 15.6.1999, Hendrich leg./coll./ Loc. 10/110” ( CLH) ; 44 exs., “ AUSTRALIA /WA/ East Kimberley , Mitchell Plateau, Mitchell Falls, 300 m, 15.6.1999, Hendrich leg. Loc. 11a/111a” ( CLH) ; 5 exs., “ AUSTRALIA /WA/ East Kimberley , Mitchell Plateau, Surveyors Pool, 150 m, 17.6.1999, Hendrich leg./coll./loc. 12/112” ( CLH) ; 20 exs., “ AUSTRALIA /WA/ East Kimberley , Mitchell Plateau , Port Warrender Road / Kalumburu Road, Lowya Creek, 290 m, 18.6.1999, Hendrich leg./loc. 13/113” ( CLH) ; 2 exs., “ AUSTRALIA /WA/ East Kimberley , Mitchell Plateau, Kalumburu Road, 25 km NW King Edward Homestead, N.N. Creek, 370 m, 18.VI.1999, Hendrich leg./loc. 14/114” ( CLH) ; 79 exs., “ AUSTRALIA /WA/ Shire of Wyndham East Kimberley , Kalumburu Road, Meelarie Creek, 5 km N Drysdale Crossing, 350 m, 18.-19.VI.1999, L. Hendrich leg./loc. 15/115” ( CLH) ; 78 exs., “ AUSTRALIA /WA/Shire of Wyndham – East Kimberley , Gibb River Road 10 km W Hann River, Snake Creek 470 m, 19.VI.1999 Hendrich leg./ COLL./ Loc. 16/116” ( CLH, ZSM) ; 65 exs., “ AUSTRALIA /WA/ East Kimberley , Gibb River Raod, Barnett River Gorge, 450 m, 19.6.1999, Hendrich leg./loc. 17/117” ( CLH) ; 276 exs., “ AUSTRALIA /WA/ Shire of Derby-West Kimberley , Gibb River Road, Galvans Gorge, 420 m, 21.6.1999, Hendrich leg./coll. Loc. 19/119” ( CLH) ; 60 exs., “ AUSTRALIA /WA/ West Kimberley , Gibb River Road , Saddler Spring near Iminji Aboriginal Community, 350 m, 22.6.1999, Hendrich leg./coll. Loc. 20/120” ( CLH) ; 27 exs., “ AUSTRALIA /WA/ West Kimberley , Gibb River Road , Bell Gorge / Bell Creek, 340 m, 22.6.1999, Hendrich leg./coll. loc. 21/121” ( CLH) ; 2 exs., “ AUSTRALIA /WA/ Shire of Derby - West Kimberley , Fitzroy Crossing Brooking Channel, 50 m, 25.6.1999, Hendrich leg. loc. 25/125” ( CLH) ; 9 exs., “ AUSTRALIA /WA/ Shire of Derby - West Kimberley , Garunji Creek, n. Geikie Gorge, 350 m, 26.6.1999, Hendrich leg/coll. Loc. 26 / 126” ( CLH, ZSM) ; 19 exs., “ AUSTRALIA /WA/ Shire of Halls Creek , 15 km E Halls Creek, 350 m, Caroline Pool, 26.VI.1999, Hendrich leg./Coll./Loc. 27/ 127” ( CLH, ZSM) ; 9 exs., “ AUSTRALIA /WA/ Shire of Halls Creek , Old Halls Creek, Elvire River, 310 m, 27.6.1999, Hendrich leg. Loc. 28/128” ( CLH) ; 74 exs., “ AUSTRALIA /WA/ Shire of Halls Creek , Purnululu N. P., Cathedral Gorge, Piccaninny Creek, 200 m, 28.6.1999, Hendrich leg. Loc. 29/ 129” ( CLH) ; 123 exs.: “ AUSTRALIA /WA/ East Kimberley , N.N. Creek 40 km W Kununurra, 50 m, 29.6.1999, Hendrich leg./ Loc. 30/130” ( CLH) ; 9 exs., “ 16.VII.1998 West Australia: Kimberleys: El Questro”, “ S 015°58´19.3´´ Pentecoste River E 127°56´41.9´´ ”, “ Dr. Wolfgang ULLRICH leg.” ( NMB) ; 5 exs., “ AUSTRALIA: No. W. A. Yearling Creek, 30 km W Kununurra on Vic. Hiway, Sept. 8, 2002, G.L.Challet ” ( CGC); 3 exs., “ AUSTRALIA: W.A. Mc Phee Creek Great Nor. [Northern] Hiway [Highway] 5 km N Doon Doon IX-8-2002, G.L.Challet ” ( CGC) ; 2 exs., “ 23.VII.1998 Austral Northern Territory Timber Creek ”, “ S 015°39´42.1´´ Dr. W. Ullrich leg. E 130°28´54.0´´ ” ( NMW); 1 ex., “ 19.VII.1998 West Australia Gibb River Road”, “ Silent Grove Bell Gorge Dr. W. Ullrich leg.”, “ S 017°00´36.3´´ E 125°13´25.3´´ ” ( NMW) .

Northern Territory. 43 exs., “ Australia /NT/ 38 km WSW Katherine, King River Bridge , 50 m, 12.V.1999, Hendrich leg./coll. Loc. 2/102” ( CLH) ; 68 exs., “ AUSTRALIA /NT/ Gregory National Park, Bullita Stock Road, 60 km S of Victoria Hwy , Limestone Creek , 40 m, 2.7.1999, Hendrich leg./Coll./ Loc. 31/ 131” ( CLH) ; 2 exs., “ AUSTRALIA /NT/ Victoria Hwy 170 km W Katherine, N.N. Creek, 50 m, 2.7.1999, Hendrich leg./Coll./ Loc. 32 / 132” ( CLH) ; 5 exs., “ AUSTRALIA / NT/ Old Stuart Hwy, Scenic Drive, 15 km W Hayes Creek, Bridge Creek , 50 m, 7.7. 1999, Hendrich leg./coll. Loc. 35/135” ( CLH) ; 6 exs., “ AUSTRALIA: No.Terr. Skull Creek minor at Victoria Hwy , Sept. 7, 2002 G.L.Challet” ( CGC) ; 2 exs., “ AUSTRALIA: No.Terr. pond at Edith Falls turn off on Hiway 1, Sept. 6, 2002 G.L.Challet” ( CGC) ; 1 ex., “ AUSTRALIA: No. [Northern] Terr. [ Territory ] Howard River at Gunnpoint Road , September 12.2002 G.L.Challet leg.” ( CGC) ; 2 exs., “ Australia: NT, Anniversary Creek , 12 km S Adelaide River Scenic Route, 43m, 22.VIII.2006, 13.19.252S 131.08.271 E, L. & E. Hendrich leg. (NT 7)” ( ZSM) ; 36 exs., “ Australia: NT, Fenton Creek at Scenic Route , 54 km S Adelaide River, 103m, 22.VIII.2006, 13.35.176S 131.20.544 E, L. & E. Hendrich leg. (NT 10)” ( CLH, ZSM) ; 1 ex., “ Australia: NT, Creek on track to Umbrawarra Gorge , 62m, 23.VIII.2006, 13.51.528S 131.49.216 E, L. & E. Hendrich leg. (NT 11)” ( ZSM) ; 385 exs., “ Australia: NT, Cullen River n. Cullen, at Stuart Hwy , 102m, 23.VIII.2006, 14.02.052S 131.56.561 E, L. & E. Hendrich leg. (NT 13)”, 1 specimen with “DNA M.Balke 1667” [green printed label] ( CLH, ZSM) ; 7 exs., “ Australia: NT, Kakadu Hwy, Harriet Creek at Hwy Cross. , 153m, 24.VIII.2006, 13.44.512S 131.54.012 E, L. & E. Hendrich leg. (NT 14)” ( CLH, ZSM) ; 85 exs., “ Australia: NT, Kakadu Hwy, Bowerbird Creek , 5 km W Mary River Roadh., large pool, 20m, 24.VIII.2006, 13.38.142S 132.10.345 E, L. & E. Hendrich leg. (NT 15b)”, 2 specimens with “DNA M.Balke 2126”, “DNA M.Balke 2127” [green printed labels] ( CLH, ZSM) . 2 exs., “ Australia: NT, Kakadu NP, small creek on the road to Gunlom , 101m, 25.VIII.2006, 13.30.422S 132.26.191 E, L. & E. Hendrich leg. (NT 16)” ( CLH, ZSM) ; 3 exs., “ Australia: NT, Kakadu NP, Plum Tree Creek, road to Gunlom 71m, 25.VIII.200613.30.516S 132.27.550 E L. & E. Hendrich leg. (NT 18)” ( CLH) ; 1 ex., “ AUSTRALIA, N.T. Near Phillip Creek on Stuart Highway, 331 m S19°18´343´´ E 134°11´104´´”, “ Hungarian Entomological Expedition in Australia leg. G. Hangay, I. Rozner, A. Podlussány, 2.XI.2000 ” ( TDMB) .

Queensland. 2 exs., “ Australia: No. Qld. Emu Creek near Petford dec 4, 1997 G.L. Challet ” ( CGC) ; 1 ex., “ Australia: No. Qld pond E. of Annan River Dec. 9, 1997 G.L.Challet ” ( CGC) ; 1 ex., “ Australia: No. Qld. Pond on Development rd. 2km S. Cookshire line Dec9, 1997 G.Challet ” ( CGC) ; 2 exs., “ Australia: N QLD, 20 km NE Mareeba, Hodzic Road , 361m, 12.IX.2006, 16.49.556S 145.27.211 E, L. & E. Hendrich leg. (QLD 28)”, “DNA M.Balke 2061”, “DNA M.Balke 2062” [green printed labels] ; 1 ex., “ Australia: N QLD, 17 km NE Mareeba Hodzic Road , 362m, 12.IX.2006, 16.51.209S 145.25.503 E, L. & E. Hendrich leg. (QLD 29)” ( CLH) . All paratypes are provided with a red printed paratype label .

Specimens with extended black colouration (65 specimens). Western Australia. 6 exs., “AUSTRALIA/WA/ East Kimberley, Gibb River Road, King Edward River Crossing , 280 m, 15.6.1999, Hendrich leg./coll./ Loc. 10/110” ( CLH) ; 1 ex., “AUSTRALIA/WA/ East Kimberley, Gibb River Raod, Barnett River Gorge , 450 m, 19.6.1999, Hendrich leg./loc. 17/117” ( CLH) .

Northern Territory. 1 ex., “Australia N.T./ Kakadu N.P. Gubara , 50 m, 25.10.1996 L.Hendrich leg. / Lok. 1” ( CLH) ; 5 exs., “NT 1km W Gubara 17/3/98 C.H.S. Watts” ( SAMA) ; 2 exs., “NT 2 K S Buley Rockhole Litchfield Nat Pk 29/3704 CHS Watts”, “ one specimen with “DNA voucher 1.” ( SAMA) ; 4 exs., “NT Nawurlandja, Kakadu Nt Pk 27/3/04 CHS Watts”, “DNA Voucher 1.” ( SAMA) ; 7 exs., “NT 5 km SE Mt Borradaile station 27.5.1999 C.Watts” ( SAMA) ; 17 exs., “NT 5 km SE Mt Borradaile station 8.10.1998 C.Watts” , 8 specimens with “ Shallow rock pool, dead leaves” ( SAMA) ; 5 exs., “ AUSTRALIA: No. Terr. Alligator River on road to Daly , Sept. 5, 2002, G.L.Challet ( CGC)” ; 2 exs., “ Australia: NT, Litchfield NP, Shady Creek, Florence Falls , 92m, 20.VIII.2006, 13.06.116S 130.47.195 E, L. & E. Hendrich leg. (NT 3)”, “DNA M.Balke 2209”, “DNA M.Balke 2210” [green printed labels] ( ZSM) ; 4 exs., “ Australia: NT, Litchfield NP, Creek near Wanggi Falls , 191m, 20.VIII.2006, 13.11.221S 130.43.327 E, L. & E. Hendrich leg. (NT 4)”, “DNA M.Balke 2194”, “DNA M.Balke 2195”, “DNA M.Balke 2196”, “DNA M.Balke 2197” [green printed labels] ( ZSM) ; 3 exs., “ Australia : NT, Nitmiluk NP, Edith Falls, Upper Pool, 123m, 23.VIII.2006, 14.10.573S 132.11.537 E, L. & E. Hendrich leg. (NT 12)”, “DNA M.Balke 2161”, “DNA M.Balke 2162”, “DNA M.Balke 2163” [green printed labels] ( ZSM) ; 2 exs., “ Australia: NT, Kakadu NP, small creek on the road to Gunlom , 101m, 25.VIII.2006, 13.30.422S 132.26.191 E, L. & E. Hendrich leg. (NT 16)” ( CLH, ZSM) ; 6 exs., “ Australia: NT, Kakadu NP, Gunlom Waterfall Area , 72m, 25.VIII.2006, 13.26.026S 132.25.141 E, L. & E. Hendrich leg. (NT 17)” , one specimen with “DNA M. Balke 1670” [green printed label] ( CLH, ZSM) . All paratypes are provided with a red printed paratype label .

Notes. According to our study of the complete material of N. thoracicus sp.n., two different complexes of specimens can be recognized: at almost each locality listed under " paratypes " we have found specimens (often in huge number) which are neither “normally coloured” ( Fig. 9 ) nor blackish to some extent ( Fig. 10 ), but belong to what we have preliminarily called “light form” ( Figs 11, 12 ; more details under “colour of "light form”). So far no intergrades between normally or blackish coloured N. thoracicus sp.n. ( Figs 9, 10 ) and the “light form” have been found, and we must state that the latter can easily be separated from the others. For some time we even have been strongly tempted to describe those of the second complex as another new species.

On the other hand we have not been able to find any constant extern morphological character—except of the colouration—which allows a safe separation of both complexes, and also the shapes of the male genitalia are more or less the same ( Figs 13, 14 ). In addition, in our Cox1 maximum likelihood tree ( Fig. 28 ) specimens of both complexes are grouped in one and the same clade. However, further studies might reveal that indeed two species complexes are involved, and this is why at present the specimens of the “light form” complex shall be treated under N. thoracicus sp.n., but not included in the paratype series and, thus, are listed as “additional material studied” below.

Additional material studied. “Light form” (1243 specimens), Western Australia. 21 exs., “AUSTRALIA/ WA/Shire of Wyndham – East Kimberley, Great Northern Hwy 50 km S Wyndham, Black Flag Creek 50 m, 13.6.1999, Hendrich leg./Loc. 4/104” ( CLH, ZSM) ; 5 exs., “AUSTRALIA/WA/ East Kimberley, Gibb River Road, Durack River Crossing , 250 m, 13.6.1999, Hendrich leg./coll./ Loc. 6/106” ( CLH, ZSM) ; 11 exs., “AUSTRALIA/WA/ East Kimberley, Gibb Range, Gibb River Road , Russ Creek Crossing, 380 m, 14.6.1999, Hendrich leg./coll. Loc. 8/108” ( CLH) ; 57 exs., “AUSTRALIA/WA/ East Kimberley, Gibb River Road, Drysdale River Crossing , 380 m, 14.6.1999, Hendrich leg./coll./loc. 9/109” ( CLH) ; 32 exs., “AUSTRALIA/WA/ East Kimberley, Gibb River Road, King Edward River Crossing , 280 m, 15.6.1999, Hendrich leg./coll./ Loc. 10/110” ( CLH) ; 45 exs., “AUSTRALIA/WA/ East Kimberley, Mitchell Plateau, Mitchell Falls , 300 m, 15.6.1999, Hendrich leg./coll. loc. 11a/111a” ( CLH) ; 47 exs., “AUSTRALIA/ WA/ East Kimberley, Mitchell Plateau, Surveyors Pool , 150 m, 17.6.1999, Hendrich leg./coll./loc. 12/112” ( CLH) ; 17 exs., “AUSTRALIA/WA/ East Kimberley, Mitchell Plateau, Port Warrender Road / Kalumburu Road , Lowya Creek , 290 m, 18.6.1999, Hendrich leg./coll. Loc. 13/113” ( CLH) ; 1 ex., “AUSTRALIA/WA/ Shire of Wyndham - East Kimberley, Mitchell Plateau, Kalumburu Road , 25 km NW King Edward Homestead, N.N. Creek, 370 m, 18.6.1999, Hendrich leg./loc. 14/114” ( CLH) ; 2 exs., “AUSTRALIA/WA/ Shire of Wyndham East Kimberley, Kalumburu Road, Meelarie Creek , 5 km N Drysdale Crossing, 350 m, 18.-19.VI.1999, L. Hendrich leg./loc. 15/115” ( CLH) ; 241 exs., “AUSTRALIA/WA/Shire of Wyndham – East Kimberley, Gibb River Road 10 km W Hann River, Snake Creek 470 m, 19.VI.1999 Hendrich leg./ COLL./ Loc. 16/116” ( CLH, ZSM) ; 58 exs., “AUSTRALIA/ WA/ East Kimberley, Gibb River Raod, Barnett River Gorge , 450 m, 19.6.1999, Hendrich leg./loc. 17/117” ( CLH) ; 142 exs., “AUSTRALIA/WA/ West Kimberley, Gibb River Road, Galvans Gorge , 420 m, 21.6.1999, Hendrich leg./coll. loc. 19/119” ( CLH) ; 106 exs., “AUSTRALIA/WA/ West Kimberley, Gibb River Road, Saddler Spring near Iminji Aboriginal Community , 350 m, 22.6.1999, Hendrich leg./coll. Loc. 20/120” ( CLH) ; 5 exs., “AUSTRALIA/WA/ West Kimberley, Gibb River Road, Bell Gorge / Bell Creek , 340 m, 22.6.1999, Hendrich leg./coll./ Loc. 21/121” ( CLH) ; 4 exs., “ 18.VII.1998 West Australia: Mt. Barnett: Manning River ”, “ S 016°39´22.1´´ Dr. W. Ullrich leg. E 125°55´43.5´´ ” ( NMB); 66 exs.: “AUSTRALIA/WA/East Kimberley, N.N. Creek 40 km W Kununurra, 50 m, 29.6.1999, Hendrich leg./ Loc. 30/130” ( CLH) .

Northern Territory. 5 exs., “ AUSTRALIA /NT/ Old Stuart Hwy , Scenic Drive , 15 km W Hayes Creek, Bridge Creek, 50 m, 7.7. 1999, Hendrich leg./coll. Loc. 35 /135 ( CLH, ZSM); 67 exs., “Australia/NT/Kakadu N.P., Jim Jim District, Gungurul Lookout, Creek ca. 50 m, S 13°59.359´E 132°19.904´, 1.11.1996, L. Hendrich/Lok. 11” ( CLH, ZSM) ; 136 exs., “ Australia /NT/ 38 km WSW Katherine, King River Bridge , 50 m, 12.V.1999, Hendrich leg./coll. Loc. 2/102” ( CLH) ; 2 exs., “ AUSTRALIA / NT/ Old Stuart Hwy Scenic Drive , 25 km WNW Hayes Creek near Burrell Creek, 50 m, 7.VII.1999 Hendrich leg. COLL. HENDRICH, Loc. 36/ 136” ( CLH) ; 10 exs., “ Australia: NT, Fenton Creek at Scenic Route , 54 km S Adelaide River, 103m, 22.VIII.2006, 13.35.176S 131.20.544 E, L. & E. Hendrich leg. (NT 10)” ( CLH, ZSM); 28 exs., “ Australia: NT, Cullen River n. Cullen, at Stuart Hwy, 102m, 23.VIII.2006, 14.02.052S 131.56.561 E, L. & E. Hendrich leg. (NT 13)” ( CLH, ZSM); 7 exs., “ Australia: NT, Kakadu Hwy, Harriet Creek at Hwy Cross., 153m, 24.VIII.2006, 13.44.512S 131.54.012 E, L. & E. Hendrich leg. (NT 14)” ( CLH, ZSM) ; 107 exs., “ Australia: NT, Kakadu Hwy , Bowerbird Creek, 5 km W Mary River Roadh., large pool, 20m, 24.VIII.2006, 13.38.142S 132.10.345 E, L. & E. Hendrich leg. (NT 15b)” , 2 specimens with “DNA M. Balke 2131”, “DNA M. Balke 2132” [green printed labels] ( ZSM) ; 3 exs., “ Australia: NT, Kakadu NP, Old Jim Jim Road, Barramundi Creek, 50m, 26.VIII.2006, 12.59.652S 132.22.928 E, L. & E. Hendrich leg. (NT 19)“ , 1 specimen with “DNA M. Balke 1666” [green printed label] ( CLH) ; 1 ex., “ Australia: NT, Magela Creek upstream, Jabiru East, 38m, 29.VIII.2006, 12.40.458S 132.55.853 E, L. & E. Hendrich leg. (NT 21)” ( ZSM) .

Queensland. 1 ex., “ Australia: No.Qld. Bismarck Creek @ Hwy Dec. 4, 1997 G.L.Challet ” ( CGC) ; 1 ex., “ Australia: No. Qld. Pond on Development rd. 2km S. Cookshire line Dec9, 1997 G.Challet ” ( CGC) ; 7 exs., “QLD Leichart Creek 8 km N of Bluewater CHS Watts Dec. 2003 ” , 2 specimens with “DNA Voucher #3” and “DNA Voucher #4” ( SAMA) ; 3 exs., “ Qld. Petford 20 km W 28/3/96 C.Watts ” ( SAMA) ; 1 ex., “ Qld. Babinda 5 km S 1/4/96 C.Watts ” ( SAMA) ; 3 exs., “ Australia: N QLD, 20 km NE Mareeba, Hodzic Road , 361m, 12.IX.2006, 16.49.556S 145.27.211 E, L. & E. Hendrich leg. (QLD 28)”, “DNA M.Balke 2066”, “DNA M.Balke 2067”, “DNA M.Balke 2068” [green printed labels] ( ZSM) ; 2 exs., “ Australia: N QLD, 4 km NW Cardwell, Ellerbeck Road , 13m, 19.IX.2006, 18.14.520S 145.58.458E, L. & E. Hendrich (QLD 38)” ( CLH) . All paratypes are provided with a red printed paratype label .

Description. Measurements. Holotype: TL = 2.80 mm, TL-H = 2.55 mm; MW = 1.30 mm. Paratypes: TL = 2.75–2.90 mm, TL-H = 2.50–2.60 mm; MW = 1.30–1.35 mm.

Colour. Antennae, palpi and head reddish-brown, posterior angles of head, near eyes and base of pronotum in middle broadly dark brown to black, in some specimens totally blackish-brown. Elytron dark brown or black with distinct yellowish markings basally, subbasally and subapically ( Fig. 9 ). Ventral side, including legs and epipleura, reddish-brown, prosternal process and metacoxal plates somewhat darkened. In several specimens yellowish pattern reduced to variable extent, thus, sometimes head, pronotum and elytron almost totally black, lacking yellowish markings on pronotum and elytra except two small spots apically ( Fig. 10 ).

Colour of “light form”. Antennae, palpi and head testaceous with two darkened spots on clypeus anteriorly. Pronotum testaceous with thin blackish band basally. Elytron dark red-brown with some well marked elongate yellow markings ( Figs 11, 12 ). Ventral side, including legs and epipleura, reddish-yellow, prosternal process and metacoxal plates somewhat darkened.

Sculpture and structure. Elongate oval. Head with scattered fine punctures and a few larger ones near base. Outline of junction of pronotum and elytra slightly sinuate, maximum width of pronotum somewhat before base. Pronotum and elytron microreticulate, and with moderately dense but rather small and well impressed punctures, weaker on disc of pronotum. Lacking any pronotal striae. Elytra lacking basal and sutural striae. Underside laterally with scattered weak to moderate punctures, denser in midline. Metacoxal lines raised, very weakly diverging anteriorly.

Male. Median lobe ( Figs 13, 14 ). In some specimens of the “light form”, the median lobe is a bit larger ( Fig. 14b ). Parameres thin, slender and very elongate, only slightly bifid anteriorly. Similar to N. samkrisi sp.n. but larger. Protarsus somewhat expanded. Mesotarsus less so. Inner edge of mesotibia straight.

Female. Tarsi simple.

Etymology. The adjective “ thoracicus ” refers to the comparatively broad thorax and pronotum of the new species.

Affinities. A variable species. In colouration the holotype and most of the paratypes of N. thoracicus sp.n. ( Fig. 9 ) very much resemble N. mjobergi ( Fig. 7 ) but can be distinguished by its generally larger size and the broad pronotum which is usually as broad as maximum width of elytra. Microreticulation and punctures on pronotum are coarser and denser than in N. mjobergi . The median lobe is of same size and shape as in N. mjobergi but in lateral view more elongated at the tip ( Figs 13, 14, 16 ). The “light form” of N. thoracicus sp.n. ( Figs 11, 12 ) very much resembles N. flavosignatus ( Figs 3, 4 ) but can be distinguished by its generally larger size and broad pronotum which is usually as broad as the maximum width of the elytra. Furthermore, the pronotal striae in N. thoracicus sp.n. are completely absent. The median lobes of N. flavosignatus and N. thoracicus sp.n. are of the same size but in ventral view the form of the aedeagus of N. thoracicus sp.n. is more slender and tapered at the tip ( Figs 13a, 14a, 15a ).

Remarks. It is notable that “black specimens” of N. thoracicus sp.n. ( Fig. 10 ) are restricted to smaller streams and intermittent creeks in monsoonal rainforest pockets in Litchfield and Kakadu National Park. The “light form” is found all over the species distribution range.

Distribution. Northern Australia (WA, NT, QLD), from the Kimberley region, Kakadu National Park, Arnhemland to northern Queensland ( Fig. 26 ).

Habitat. The habitat is similar to that of N. denticulatus , N. flavosignatus and N. mjobergi with which it usually occurred ( Figs 30, 35 , 36, 37 ).

Figures

FIGURE 28. Phylogram of the tree obtained using GARLI and with cox1 data for Neobidessodes alone. Node support, when above 50%: bold (GARLI bootstrap), normal font (TNT parsimony jackknife values). Abbreviations behind N. thoracicus sp.n.: “b.s” = black specimens; “l.f.” = “light form”.

FIGURES 9–12. 9) N. thoracicus sp.n. (paratype); 10) N. thoracicus sp.n. (paratype, “black specimen”); 11) N. thoracicus sp.n. (“light form”, WA, Kimberley Region, 50 km S Wyndham, Black Flag Creek); 12) N. thoracicus sp.n. (“light form”, NT, Kakadu N.P., Jim Jim District, Gungurul Lookout) (scale bar = 1 mm) (Photos: A. Riedel).

FIGURES 13–17. Median lobe of aedeagus in ventral (a) and lateral view (b), and right paramere in lateral view (c): 13) Neobidessodes thoracicus sp.n. (paratype); 14) N. thoracicus sp.n. (“light form”); 15) N. flavosignatus; 16) N. mjobergi and 17) N. samkrisi sp.n. (scale bar = 0.5 mm) (Photos: L. Hendrich).

FIGURES 25–26. Distribution of Neobidessodes: 25) N. mjobergi; 26) N. thoracicus sp.n..

FIGURES 30–35. Habitats of Neobidessodes: 30) Slow flowing stream and rest pool in monsoonal rainforest at Gubara (Kakadu NP, NT), habitat of “black specimens” of Neobidessodes thoracicus sp.n.; 31) NT, Manton Dam Recreation Area, 46 km S Darwin (NT 1), habitat of N. denticulatus, N. flavosignatus and N. mjobergi; 32) NT, Finnis River 10 km W Batchelor (NT 2), habitat of N. mjobergi and N. denticulatus; 33) NT, Litchfield NP, Shady Creek, Florence Falls (NT 3), habitat of N. grossus; 34) NT, Nitmiluk NP, Edith Falls, Upper Pool (NT 12), habitat of N. grossus; 35) NT, Kakadu Hwy, Harriet Creek at Hwy Crossing (NT 14), habitat of N. grossus and N. thoracicus sp.n. (Photos: L. Hendrich).

FIGURES 36–41. Habitats of Neobidessodes: 36) NT, Kakadu NP, Creek on the way to Gunlom (NT 16), habitat of black specimens and the typical form of Neobidessodes thoracicus sp.n.; 37) Restpools in river at Gungurrul Lookout in Kakadu NP, October 1996, habitat of N. denticulatus, N. flavosignatus, N. mjobergi and N. thoracicus sp.n.; 38) S QLD, 8 km SE Miriam Vale, road to Agnes Water, Oyster Creek (QLD 50), habitat of N. denticulatus; 39) S QLD, N Brisbane, Caboolture/Beerburrum road, near King John Creek (QLD 62), shallow roadside swamp, habitat of N. denticulatus; 40) S NSW, 6.5 km SW Eden, Towamba Road 2 km N Nullica, 556 m (NSW 111), habitat of N. bilita; 41) S VIC, Simpsons Creek 12 km SW Orbost at Princess Hwy (VIC 116), habitat of N. bilita (Photos: L. Hendrich).

FIGURES 5–8. Habitus of 5) Neobidessodes samkrisi sp.n. (holotype, male); 6) N. grossus; 7) N. mjobergi; 8) Neobidessodes bilita (female) (scale bar = 1 mm) (Photos: A. Riedel).

FIGURES 1–4. Habitus of 1) N. denticulatus (WA, Pilbara, Millstream Chichester National Park, Fortescue River side branch); 2) N. denticulatus (NT, Kakadu N.P., Jim Jim District, Gungurul Lookout); 3) N. flavosignatus (WA, East Kimberley, Gibb Range, Gibb River Road, Russ Creek Crossing); 4) N. flavosignatus (NT, Manton Dam Recreation Area, 46 km S Darwin) (scale bar = 1 mm), (Photos: A. Riedel).