Taxonomic revision of the Australian predaceous water beetle genus Carabhydrus Watts, 1978 (Col. Dytiscidae, Hydroporinae, Hydroporini) Author Hendrich, Lars Zoologische Staatssammlung, Münchhausenstrasse 21, D- 81247 München, Germany. E-mail: hendrich 1 @ aol. com Author Watts, Chris H. S. South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia. E-mail: watts. chris @ saugov. sa. gov. au text Zootaxa 2009 2009-03-23 2048 1 1 30 https://biotaxa.org/Zootaxa/article/view/zootaxa.2048.1.1 journal article 10.11646/zootaxa.2048.1.1 1175-5326 5323018 Key to Species of Carabhydrus 1. Species smaller than 2 mm , median lobe in ventral aspect strongly tapered at apex ( Fig. 26 ); NE QLD ..................... ................................................................................................................................................................ C . storeyi sp.n. 1'. Species longer than 2 mm ............................................................................................................................................. 2 2. Elytron more or less uniformly pale testaceous to reddish black to black, without basal or subbasal spots............... 6 2'. Elytron black or brown except a large reddish subbasal spot and on some specimens also the apex .......................... 3 3. Species larger than 3 mm . Largest species of the genus ( 3.1–3.6 mm ), pronotum more parallel sided ( Fig. 2 ) and at base broader than head, with three deep longitudinal depressions on elytra, first mesotarsal segment in male formed like a triangular hook ( Fig. 15 ); N NSW, S VIC.................................................................................... C . innae sp.n. 3'. Species smaller than 3 mm , first mesotarsal segment in all known males without a triangular hook.......................... 4 4. Body flattened, more rounded, elytral grooves well defined and very deep, elytral spots less defined ( Fig. 5 ), in female half of elytra covered by a fine microreticulation, male unknown; N NSW ............................... C. turaki sp.n. 4'. Body more convex, elytral grooves less defined, elytral spots well defined ( Figs 1, 3 ), in female only apex of elytra covered with fine microreticulation .............................................................................................................................. 5 5. Pronotum black ( Fig. 1 ), aedeagus in ventral view with apex of each apical lobe sharply pointed and finger-like ( Fig. 10 ); VIC, NSW, ACT .................................................................................................................................. C. andreas 5'. Pronotum reddish, only base of pronotum black ( Fig. 3 ), male mesotibia with a well developed subapical tooth on inner edge, aedeagus in ventral view with apical lobes blunt and broadly rounded ( Fig. 24 ); S QLD, N NSW .......... ...................................................................................................................................................................... C. plicatus 6. Dorsal side pale testaceous or brown, eyes about half normal size or absent .............................................................. 7 6' Dorsal side blackish-brown or black, eyes normal ..................................................................................................... 8 7. Eyes present, ventral side pale to dark brown ( Fig. 8 ), pronotum narrower than elytra in middle, basal part of median lobe with sclerotized, broad and shell-like coverage ( Figs 16, 17 ), S NSW ................................ C . janmillerae sp.n. 7'. Eyes absent, pale testaceous ( Fig. 6 ), pronotum broader than elytra in middle, male unknown, stygobitic species; NSW ........................................................................................................................................................ C. stephanieae 8. Aedeagus in ventral aspect ( Fig. 22 ) with a deep, broad, subapical notch on each side delimiting a broad, apically bilobed apex; VIC, NSW, TAS ......................................................................................................................... C. niger 8'. Aedeagus in ventral aspect ( Fig. 20 ) with a narrow subapical notch on each side, apex subtriangular and not broadly rounded ......................................................................................................................................................................... 9 9. Elytron with mesal groove extending almost to apex; pronotum with lateral margin more or less evenly rounded except for short sinuation before posterolateral angle; aedeagus in lateral aspect lacking ventromedial projections ( Fig. 21 ); NE QLD .................................................................................................................................. C. mubboonus 9'. Elytron with mesal groove shallow in apical third and discontinuous before apex; pronotum narrow, sides sinuate basally and more or less straight and parallel before posterolateral angles; aedeagus in lateral aspect ( Fig. 19 ) with a pair of ventromedial projections; N NSW ................................................................................................. C. monteithi