Sandracottus bakewellii bakewellii ( Clark, 1864 )

Hendrich, Lars & Brancucci, Michel, 2025, Revision of the Oriental and Australasian diving beetle genus Sandracottus Sharp, 1882 (Coleoptera, Dytiscidae, Dytiscinae), ZooKeys 1223, pp. 87-147 : 87-147

Sandracottus bakewellii bakewellii ( Clark, 1864)

Figs 1 , 12 , 23 , 31 , 32 , 46

Hydaticus bakewellii Clark, 1864: 210 (type locality Moreton Bay, Queensland, Australia).

Sandracottus bakewellii ( Clark, 1864): Sharp 1882: 687 (descr.); Régimbart 1899: 336 (descr.); Zimmermann 1920: 234 (cat.); Watts 1978: 148 (descr.); Watts 1985: 26 (cat.); Lawrence et al. 1987: 356 (cat.); Larson 1993: 59 (faun., ecol.); Larson 1997: 273 (faun., ecol.); Hendrich et al. 2019: 46 (faun., ecol., tax.); Hájek and Nilsson 2024: 91 (cat.).

Type material.

Lectotype: Male, “ Lectotype ”, “ Type, 6756 ”, “ Bakewelliii ”, “ Hydaticus bakewellii Clk. Det. C. Watts 1979 ” ( NHMUK) . Paralectotypes: 1 female, “ Moreton Bay ”, “ Sandracottus bakewellii Clk ”, “ Bakewellii Clark Moreton Bay ”, “ Syntype ” ( NHMUK) ; 1 male, “ Moreton Bay ”, “ Bowring 6347 * ”, “ Syntype ” ( NHMUK) ; 1 male, “ Nova Holland . ”, “ Syntype ” ( NHMUK) . Examined.

Additional material.

(183 specimens): Australia. • Northern Territory: 1 ex., “ N. Queensland Bloomfield River ” ( ZHMB); 2 ex., “ Moreton Bay ” ( NHMUK) 1 ex., “ Darwin, N. T., 1930 ” ( MNHN); 1 ex., “ Northern Austr. ” ( MNHN); 1 ex., “ Northern Territory, F. E. Wilson coll. ” (without further data) ( VIC); 1 ex., “ Tindal, 7. XI. 1967, W. J. M. Vestjens leg. ” ( ANIC); 1 ex., “ Northern Territory, A. H. Elston collection ” ( AM); 1 ex., “ Burrells Creek, 17 miles S Adelaide River, 7. IV. 1971, T. Weir leg. ” ( NTM); 1 ex., “ Edith Falls, in pool, 23. VIII. 1982, G. Allen & B. Russell leg. ” ( NTM); 1 ex., “ Adelaide River Hills, 24 km N Robin Falls turn off, in pool, 17. X. 1982, G. Husband leg. ” ( NTM); 3 exs., “ Australia, Northern Territory, Katherine Gorge, Butterfly Gorge Walk, 150 m, 4. VII. 1999, Hendrich leg., Loc. 33 / 133 ” ( CLH); 1 ex., “ Northern Territory, Burnside Stn., Brocks Crk., 25. VIII. 1932, 25-018562, S 13.46. 667 E 131.41. 67, T. G. Campbell leg. ” ( ANIC); 1 ex., “ Australia NT, 23 km S Adelaide River, permanent creek at Scenic Route, 137 m, 22. VIII. 2006, 13.26. 593 S 131.11. 012 E, L. & E. Hendrich leg. ” (NT 9) ( ZSM). • Queensland: 1 ex., “ Toowong District N. Queensland OE Janson sons ” ( USNM); 1 ex., “ Rockhampton Sub. Distr. S. F. R. 5 Cpt. L. A. 17. VIII. 1976 R. A. Yule Dept. For. Qld / Acc. 1241 / 15 ”, “ QFIC specimen incorporated into QDPC March 2010 ” ( QDPIB); 1 ex., “ Gayndah QLD 17. II. 1963 H. A. Rose ” ( QM); 1 ex., “ Mt. Glorious Q. 7. III. 1959 K. Korboot ” ( QM); 1 ex., “ Brisbane 6. X. 1963 I. R. Bock ” ( QM); 7 exs., “ Moolyamba Creek 9. V. 1948 J. L. Wassell ” ( QM); 1 ex., “ N Queensland, Cooktown, Eichhorn ” ( MNHN); 4 exs., “ Rockhampton (Australie), Thoret 1870 ” ( MNHN); 2 exs., “ Dawson district, Barnard coll. ” ( MNHN, NMB); 2 exs., “ Coll. French Queensland “ ( MNHN, RMNH); 2 exs., “ Hydaticus bakewellii Clk Type mihi D. S. [David Sharp] Queensland 983 “ ( NHMUK); 1 ex., “ Bagot Creek ” [SE Queensland, West of Dalby] ( AUS); 1 ex., “ Nova Holland Moreton Bay ” ( NHMUK); 1 ex., “ Brisbane ” ( AM); 1 ex., “ Brisbane Mt. Cootha 14. XI. 1939 D 714 ” ( QDPIB); 1 ex., “ Brisbane ” ( NHMUK); 1 ex., “ Rockhampton ” ( NHMUK); 2 exs., “ Townsville ” ( MNHN); 2 exs., “ Carnavon Gorge 26. I. 1982 J. Sedlacek leg. ” ( NMB); 1 ex., “ North Queensland Mutchilba A. D. Selby leg., F. E. Wilson coll. ” ( VIC); 1 ex., “ Emu Creek pot hole 19. X. 1940 J. Dewaney leg. ” ( VIC); 2 exs., “ Rollingstone S. R. E. Brock Collection ” ( ANIC); 12 exs., “ Bouldercome, 14. V. 1966 ”, “ A. N. C. G. L. Gooding Collection donated to ANIC 1979 ” ( ANIC); 6 exs., “ NW Queensland 28 N by E of Musselbrook Mining Camp Amphitheatre Springs S 18.21 E 138.11 12. V. 1995 T. Weir leg. ” ( ANIC); 1 ex., “ North Queensland Eungella NP Broken River 31. VIII. - 8. IX. 1998 Neave Edwards Powell Sutrisno & Hebbard leg. ” ( ANIC); 1 ex., “ North Queensland 45 km N Aurukun 25. II. 1981 M. Robinson leg. ” ( AM); 1 ex., “ Mt. Carbine T. W. Gamble leg. ” ( AUS); 1 ex., “ Queensland Carmila North coast Lancel. 1928 N. McArthur leg. ” ( AM); 2 exs., “ Blackall River F. Witteron leg. ” ( QDPIB); 1 ex., “ Highlands 4 km S Emmet, S 24 ° 57 ' E 144 ° 26´, 19. IV. 2002, ex spring, sandstone gully, R. J. Felsham leg. (8951) ” ( QM); 4 exs., “ N Queensland W. Cape York Peninsula Brown Creek pond VI. 1982 P. Saenger leg. ” ( QM); 1 ex., “ near Mt. Molloy, Rifle Creek 3. I. 1990 ANZSES Expedition ” ( QM); 1 ex., “ ME Queensland, Blackdown Tableland Stoney Creek via Dingo at light 17–19. XII. 1985 S. Hamlet leg. ” ( QM); 1 ex., “ N Queensland, White Mts. NP 2 km NE of RGSQ / AG Base Camp S 20.26 E 144.51 5–7. IV. 2000, deep rocky pool, cloudy, sandy bottom, vegetation, half shade, T. Weir leg. ” ( ANIC); 2 exs., “ N Queensland White Mts. NP, 53 km NE Prairie IX. 1995, D. J. Cook leg. ” ( QM); 2 exs., “ C Queensland Mt. Abbott summit area S 20 ° 06´, E 147 ° 45´, 750–1000 m, 8–10. XII. 1996, G. Monteith & D. J. Cook leg. ” ( QM); 2 exs., “ Watsonville 10 km W Herberton 9. XII. 1990 D. J. Larson leg. ” ( ANIC, QM); 2 exs., “ Brisbane 30. IV. 1912 H. Hacker ” ( QM); 3 exs., “ Sutton Collection, donation December 1964 ” ( QM); 1 ex., “ Queensland ”, “ coll. Felsche Geschenk 1907 ”, “ Sandracottus bakewellii det. Gschwendtner ” ( SMTD); 1 ex., “ near Collins, Catherine Creek, 20. XI. 1990, T. Weir leg. ” ( ANIC); 1 ex., “ Lake Mitchell 40 km N Mareeba 21. IX. 1990 D. J. Larson leg. ” ( ANIC); 1 ex., “ SE Mt. Carbine Saddle Bag Creek 15. XI. 1990 D. J. Larson leg. ” ( ANIC); 3 exs., “ Australia Queensland Atherton Tableland 30 km NNW Mareeba near Mitchell lake 9. XI. 1996 Hendrich leg. ” ( CLH); 1 ex., “ Julatten 11. IV. 1984 at light, K. & E. Carnaby leg. ” ( ANIC); 1 ex., “ North Queensland Julatten 2. IV. 1977 Walford-Huggins leg. ” ( CLH); 1 ex., “ Queensland Brisbane I. 1931 ” ( CLH); 1 ex., “ Mareeba Road, Clohesy River Road, I. 1974, A. & M. Walford-Huggins ” ( CLH); 1 ex., “ Hell Hole Gorge NP, S 25.34 E 144.11, X. 1997, at light in open forest T. Weir leg. ” ( ANIC); 1 ex., “ N Queensland, Coen River 1 km E of Rokeby Mungkan Kandju River, at light, S 13.39 E 142.41, 22. VII. 1998, A. A. Calder leg. ” ( ANIC); 9 exs., “ North Queensland, Cape Tribulation 26. - 27. XII. 1969 leg. G. Hangay ” ( CLH, TDMB); 1 ex., “ Queensland ”, “ Coll. Franklin Müller ”, “ Sandracottus bakewellii det. A. Zimmermann ” ( DEI); 1 ex., “ Queensland, Wallaroo, 17. I. 1968, G. Hangay ” ( CLH); 12 exs., “ Northern Queensland, Silver Valley, Samml. A. Zimmermann ( ZSM); 1 ex., “ Silver Valley N. Queensl. III ”, “ Coll. Gärtner ”, “ Sandracottus bakewellii Clark ” ( DEI); 2 exs., “ Queensland ”, “ Coll. Franklin Müller ” ( ZSM); 1 ex., “ Queensland Archer River 28. VII. 1992 S 13.55 E 143.05 Zborowski, P. & Nielsen, E. S. ” ( ANIC); 1 ex., “ Queensland, Brisbane (general), I. 1931, S 25.01. 856 E 27.46. 667,153.0333, A Misko, S. leg. ” ( ANIC); 2 exs., “ Queensland, Mary Creek, S 16.33 E 145.12. 5 at light 4. XII. 1968 E. B. Britton & S. Misko leg. ” ( ANIC); 1 ex., “ Queensland Calliope River 23 km SE of Gladstone [approx. 23 km SW of Gladstone] 23. I. 1970, at light, S 23.83. 333 E 151.21. 67 S. Misko leg. ” ( ANIC); 5 exs., “ S QLD, 40 km E Bundaberg, Tusky Creek, 9 m, 26. IX. 2006, 24.39. 139 S 152.01. 477 E, L. & E. Hendrich leg. (QLD 52) ”; 5 exs., “ S QLD, Winfield, Winfield Road, forest pool, 21 m, 26. IX. 2006, 24.34. 084 S 152.00. 513 E, L. & E. Hendrich leg. (QLD 54) ” ( ZSM, CLH); 3 exs., “ NH [= Neuholland] Coll. Plason ” ( NMW); 2 historical specimens leg. Bauer! [beginning of 19 th century, without any detailed locality data, Jäch pers. comm. 2010]. • Western Australia: 1 ex., “ Kununurra, Cave Springs, ex. pool 9. X. 1966 ” ( WADA); 3 exs., “ Kimberely Research Station, 16. II. 1959, K. T. Richards leg. ” ( WADA); 3 exs., “ 130 miles SE of Broome, 15. IX. 1924, A. S. Cudmore leg. ” ( VIC); 2 exs., “ Kimberley district N. V. Mjöberg ”, “ Samml. A. Zimmermann ” ( ZSM); 1 ex., “ Australia occ. ” [= Western Australia] Lea leg. ”, “ Sandracottus bakewellii Clark Dr. F. Guignot det. ” ( TDMB); 3 exs., “ Western Australia, 163 km SE by E Broome 5. VIII. 1976 Common I. F. B. leg. ” ( ANIC); 2 exs., “ Western Australia, King Sd ” [King Sound, area around Derby] ( ANIC). • Unknown states: 1 ex., “ Australia ”, “ Coll´n J. D. Sherman Jr. 1926 ” ( USNM); 2 exs., “ Australie ” ( MNHN); 1 ex., “ Australia 7642 ” ( NHMUK); 2 exs., “ Australia Blackburns Collection ”, “ Sandracottus guttatus identified by L. A. Lea ” ( AUS); 4 exs., “ Mootwingie 15. IX. 195 ” ( AUS). • Doubtfull records: 1 ex., “ Victoria ” ( MNHN); 1 ex., “ S. West Australia ” ( MNHN); 2 exs., “ Museum Paris Tasmanie Verreaux 3-47 ” ( MNHN).

Redescription.

Body broad oval, shiny testaceous with dark brown markings. Ventral side completely ferrugineus brown except testaceous fore and mid legs.

Head testaceous with posterior part broadly black; black part prolonged along eyes and protruding on frons. Surface shiny, very superficially shagreened. Punctation consisting of dense punctures, irregular in size and of larger and much sparser ones; these more numerous on frons. Clypeal grooves and punctures alongside eyes present, punctures medium-sized and coalescent. Antennae testaceous; antennomeres slender, antennomere V 5 × as long as broad.

Pronotum testaceous with median black marking reaching from posterior to anterior margin; long and broad on posterior, distinctly shorter and narrower on anterior margin and strongly constricted in middle. Surface very slightly and superficially shagreened, with very dense punctation; punctures medium-sized not constant in size, distance 2–3 × that of their diameter. Anterior rows of punctures interrupted in middle, punctures large and coalescent. Posterior row of punctures medially with large and coarsely impressed punctures in middle.

Elytra shiny, black, with larger basal, subbasal and apical elytral markings (Fig. 1 ). Epipleura ferrugineus brown. Surface distinctly shagreened and covered with small and dense punctures and with larger and much sparser ones. Puncture lines with groups of medium-sized punctures mostly grouped by five or six punctures; discal row almost complete. Sutural puncture line marked only by few punctures.

Ventral side dark brown. Fore and mid legs testaceous, hind legs ferrugineus brown to dark brown. Prosternal process short and broad, 1.6 × longer than broad, finely but distinctly sculptured; posterior margin broadly rounded. Metatibia with sparse medium-sized to large punctures on outer proximal part. Ventrites II – VI very superficially shagreened, distinctly longitudinally wrinkled on whole lateral parts, densely covered with very small punctures and larger and sparser ones. Posterior margins rounded, deeply bordered with a row of large and coalescent punctures in middle of each side alongside margin.

Measurements: TL = 13.5–14.5 mm, TL-h = 12.5–13.5 mm, TW = 8.0–9.0 mm.

♂. Protarsomeres I – III strongly enlarged with three larger suckers and numerous smaller one. Mesotarsomeres I – III with two rows of small suckers. Median lobe of aedeagus in ventral view broadened in apical third, then tapering towards apex (Fig. 12 a ). Parameres elongate and pointed at apex (Fig. 12 b ).

♀. Similar to male. Tarsomeres not enlarged. Microsculpture on ventrite VI as in male.

Differential diagnosis.

Colour of dorsal surface and shape of the median lobe distinguish S. bakewellii from all other species of the genus. It is the only species which occurs in Australia. The subspecies S. bakewellii bakewellii can be separated from S. bakewellii guttatus by the broader and not interrupted yellowish anteromedian, posteromedian and preapical markings (Figs 46 , 47 ).

Distribution.

Northern Australia, east coast from Northern Queensland south to Brisbane (Fig. 23 ). Specimens were collected from near sea level to 1000 m a. s. l.

Habitat.

Sandracottus bakewellii inhabits large (0.5 m depths or more) pools of seasonal streams and creeks, spring fed pools often with dark or gloomy water. The adults are generally found amongst tangles of roots and in places where the water is shaded. Habitats are often enriched with dead leaves and twigs (Figs 31 , 32 ).

Figures

Figure 23. Distribution of Sandracottus bakewellii bakewellii [black dots] and S. bakewellii guttatus [red squares] in Australia.

Figures 1–3. Habitus of 1 Sandracottus bakewellii bakewellii (Northern Territory, Australia) 2 S. bizonatus (Borneo, Sabah, Kinabalu) 3 S. chevrolati (Sumba Island, Indonesia).

Figures 12–15. Median lobe of aedeagus in ventral view (a), and right paramere in lateral view (b) 12 Sandracottus bakewellii bakewellii 13 S. bizonatus 14 S. chevrolati and 15 S. dejeanii.

Figures 31–36. Habitats of Sandracottus 31 Australia, Northern Territory, 50 km S Adelaide River, creek at Scenic Route (NT 9) and 32 South Queensland, Winfield, Winfield Road, rest pool (QLD 54), habitats of S. bakewellii bakewellii (photos: L. Hendrich) 33 Northern Territory, Ormiston Gorge, habitat of S. bakewellii guttatus (photo: M. Baehr) 34 Pakistan, Sistan va Baluchestan Prov., Pir Sohrab env., rest pool in wadi, habitat of S. dejeanii (photo: J. Hájek) 35 India, southern Madhya Pradesh, Hoshangabad District, Pagara – Pachmarhi road, ca 5 km NNE Panchmarhi, Panar Pani, habitat of S. dejeanii and S. festivus (photo: M. Jäch) 36 Indonesia, Irian Jaya, Nabire, Nabire-Ilaga track, km 62, habitat of S. femoralis (photo: L. Hendrich).

Figures 46–49. Colouration and habitus of 46 Sandracottus bakewellii bakewellii (Australia, Northern Queensland, Atherton Tableland, Mareeba) 47 S. bakewellii guttatus (Australia, Northern Territory, Ormiston Gorge) 48 S. bizonatus (Borneo, Sabah, Keningau) 49 S. chevrolati (Indonesia, Sumba Island, Waingapu).