Carabhydrus, Watts, 1978

Hendrich, Lars & Watts, Chris H. S., 2009, Taxonomic revision of the Australian predaceous water beetle genus Carabhydrus Watts, 1978 (Col. Dytiscidae, Hydroporinae, Hydroporini), Zootaxa 2048 (1), pp. 1-30 : 28-29

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

Figures

FIGURES 20–27. Median lobe of aedeagus in ventral and lateral view (scale bar 0.2 mm): 20, 21–Carabhydrus mubboonus; 22, 23—C. niger; 24, 25—C. plicatus; 26, 27—C. storeyi sp.n.

FIGURES 1–4. Habitus of Carabhydrus. 1—Carabhydrus andreas (male); 2—C. innae sp.n. (holotype, male); 3—C. plicatus; 4—C. storeyi sp.n. (paratype, male) (scale bar 1 mm) (Photos: L. Hendrich).

FIGURES 10–19. Median lobe of aedeagus in ventral and lateral view (scale bar 0.2 mm): 10, 11—Carabhydrus andreas and 12, 13—C. innae sp.n.; 14, 15—C. innae sp.n. right paramere (14) and first two mesotarsal segments (15) in dorsal view (scale bar 0.2 mm). Median lobe of aedeagus in ventral and lateral view: 16, 17—C. janmillerae sp.n. and 18,19—C. monteithi.

FIGURES 5–9. Habitus of Carabhydrus. 5—Carabhydrus turaki sp.n. (holotype, female); 6—C. stephanieae (paratype); 7—C. mubboonus (female); 8—C. janmillerae sp.n. (paratype, female); 9—C. niger (female) (scale bar 1 mm) (Photos: L. Hendrich).