Neobidessodes bilita ( Watts, 1978 )

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 : 11-14

Neobidessodes bilita ( Watts, 1978) comb.n.

( Figs 8 , 18 , 22 , 27 , 28 , 40, 41 )

Bidessodes bilita Watts, 1978 : Watts (1978: 30); Watts (1985: 24); Lawrence et al. (1987: 335); Biström (1988: 7); Nilsson (2001: 111); Watts (2002: 31, 43); Balke & Ribera (2004: 115); Hendrich & Balke (2009: 49).

Type locality. Stanthorpe, Southeast Queensland, Australia.

Type material. Holotype. Male : “Stanthorpe Q [Queensland] Jan 1961, C W [Chris Watts leg.]” [handwritten label], “ Holotype ” [printed red label], “ Holotype Bidessodes bilita C.Watts det. 1976” [white, handwritten label with red frame] ( ANIC).

Paratypes. 1 male and 1 female, same data as holotype, “ Paratype Bidessodes bilita C.Watts det. 1976” [white, handwritten label with blue frame] ( SAMA) ; 1 female: “ Cabbage Tree Creek, Canberra-coast road, New South Wales, 19.VIII.1965 ”, “ Paratype Bidessodes bilita C.Watts det. 1976” [white, handwritten label with blue frame] ( SAMA) .

Additional material studied. 19 specimens. New South Wales . 12 exs., S NSW, 6.5 km SW Eden, Towamba Road 2 km N Nullica, 556 m, 16.XI.2006, 37.04.412S 149.51.200 E, L. & E. Hendrich leg. ( NSW 111 ) , two specimens with “DNA M.Balke 1900”, “DNA M.Balke 1901” [green printed labels] ( CLH, ZSM) .

Victoria: 1 ex., S VIC, 12 km SW Orbost, Simpson Creek , 30.XI.1998, C.H.S. Watts leg. ( SAMA) ; 3 exs., S VIC, 12 km SW Orbost, Simpson Creek , 5.XI.1997, C.H.S. Watts leg. ( SAMA) ; 2 exs., S VIC, 12 km SW Orbost, Simpson Creek , 16.I.1997, C.H.S. Watts leg. ( SAMA) ; 1 ex., S VIC, Simpsons Creek 12 km SW Orbost at Princess Hwy , 31 m, 18.XI.2006, 37.45.095S 149.20.436 E, L. & E. Hendrich leg. ( VIC 116 ) ( CLH) .

Re-description. Measurements. TL = 2.20–2.25 mm, TL-H = 2.00– 2.05 mm; MW = 1.00– 1.05 mm.

Colour: Antennae and palpi yellowish, head testaceous, somewhat darkened near eyes, pronotum testaceous. Elytron dark brown with some rather vague sublateral and lateral oblong yellow markings ( Fig. 8 ). Ventral side, including legs and epipleura, testaceous, prosternal process and metacoxal plates somewhat darkened.

Sculpture and structure. Elongate oblong. Head with relative strong punctures particularly at base. Pronotum and elytron with rather dense, medium-sized punctures and weakly to moderately microreticulate, finely pubescent. Pronotal striae deep and well marked, length 1/4 to 1/3 of that of pronotum, weakly incurved. Elytra lacking basal and sutural striae. Elytron with a weak subapical flange or bulge. Underside with a few moderately large weak punctures at sides, midline with moderately dense smaller punctures. Metacoxal lines raised, well separated, weakly diverging anteriorly.

Male. Pro- and mesotarsi weakly expanded. Mesotibia quite strongly curved especially on inner edge. Median lobe of aedeagus ( Fig. 18a, b ) and right paramere ( Fig. 18c ).

Female. Pro- and mesotarsi simple. Inner edge of mesotibia nearly straight.

Affinities. The small size, the almost unicolorous dorsal surface, the slightly flanged subapical part of elytra, the well marked pronotal striae, and the strongly curved male tibiae distinguish N. bilita from all other known Australian Neobidessodes . Furthermore, the form of the median lobe and parameres are very distinctive ( Fig. 18a, b, c ).

Distribution. Victoria, New South Wales and Southeast Queensland ( Watts 1985, Lawrence et al. 1987) ( Fig. 22 ).

Habitat. A rarely collected species. Neobidessodes bilita inhabits rest pools of smaller intermittent streams and creeks, mainly in wet forested areas, with peaty water and at least partly shaded by dense stands of shrubs and emergent vegetation. The only new records are known from two lowland creeks in the southeastern border region between New South Wales and Victoria. At Eden ( Fig. 40 ) N. bilita is associated with the dytiscids Antiporus femoralis (Boheman, 1858) , Chostonectes sharpi Sharp, 1882 , Exocelina australiae (Clark, 1863) , Hyphydrus elegans (Montrouzier, 1860) , Limbodessus gemellus (Clark, 1862) , Necterosoma penicillatum (Clark, 1862) , Platynectes spec. , Rhantus suturalis (W.S. Macleay, 1825) , Sternopriscus hansardii (Clark, 1862) and S. tarsalis Sharp, 1882 . At Simpson Creek ( Fig. 41 ) the species co-occurs with A. femoralis , Chostonectes gigas (Boheman, 1858) , C. sharpi , Hydrovatus opacus Sharp, 1882 , Hyphydrus elegans , Limbodessus compactus (Clark, 1862) , L. gemellus , N. penicillatum , N. undecimlineatum (Babington, 1841) , R. suturalis , Sternopriscus clavatus Sharp, 1882 , S. mouchampsi Hendrich & Watts, 2004 and S. tarsalis . Contrary to all other species of the genus, except N. grossus , it seems that at most sites the population density is quite low as it was not possible to collect large series of specimens.

Figures

FIGURES 22. Distribution of Neobidessodes: 22) N. bilita (squares) and N. denticulatus (dots).

FIGURE 27. Phylogram of the tree obtained using GARLI and cox1 and 16S data for Australasian Bidessini, Neotropical Bidessodes and outgroups. Node support, when above 50%: bold (GARLI bootstrap), italics (MrBayes posterior propablities>0.5, x100), normal font (TNT jackknife values). Note: “Clypeodytes migrator” will be transferred to Leiodytes in a forthcoming revision (Hendrich et al. in prep.).

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 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 18–20. Median lobe of aedeagus in ventral (a) and lateral view (b), and right paramere in lateral view (c): 18) Neobidessodes bilita; 19) N. denticulatus and 20) N. grossus (scale bar = 0.5 mm) (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).