Comaldessus stygius Spangler and Barr, 1995

Miller, Kelly B., Gibson, James R. & Alarie, Yves, 2009, North American Stygobiontic Diving Beetles (Coleoptera: Dytiscidae: Hydroporinae) with Description of Ereboporus naturaconservatus Miller, Gibson and Alarie, New Genus and Species, from Texas, U. S. A, The Coleopterists Bulletin 63 (2), pp. 191-202 : 196-197

Comaldessus stygius Spangler and Barr, 1995

( Figs. 6–8 )

Comaldessus stygius Spangler and Barr 1995: 302 ; Nilsson 2001: 119; Larson et al. 2000: 101.

Type Species. Comaldessus stygius Spangler and Barr, 1995 by original designation.

Type Locality. U.S.A., Texas, Comal County, New Braunfels, Landa Park , Comal Spring #3 .

Diagnosis. This species can be distinguished from other taxa within Bidessini using the following character combination: 1) eyes rudimentary, indicated by only a few ommatidia; 2) metacoxal lines absent; 3) occipital line absent ( Fig. 6 ); 4) basal pronotal and basal elytral striae (‘‘plicae’’) present ( Fig. 6 ).

Discussion. Comaldessus stygius was described from twelve specimens collected in drift nets from Comal Springs (Spangler and Barr 1995), a system of artesian springs.

Relationships. This species is clearly a member of the tribe Bidessini based on the 2-segmented parameres ( Biström 1988) and the presence of basal pronotal and elytral striae ( Fig. 6 ) which are characteristic of many Bidessini ( Biström 1988). Spangler and Barr (1995) speculated that the species is related to Trogloguignotus Sanfilippo and Uvarus Guignot and that both Trogloguignotus and Comaldessus are derived from within the species-rich, plesiomorphic Uvarus , though without a cladistic analysis of this problematic tribe, it is difficult to make definitive conclusions.

Figures

Figs. 6–16. Subterranean Dytiscidae. 6–8) Comaldessus stygius, 6) dorsal habitus, 7) male genitalia, ventral aspect, 8) male genitalia, right lateral aspect. 9–12) Stygoporus oregonensis, 9) dorsal habitus, 10) male median lobe, right lateral aspect, 11) male median lobe, ventral aspect, 12) male right lateral lobe, right lateral aspect. 13–16) Haideoporus texanus, 13) dorsal habitus, 14) male median lobe, right lateral aspect, 15) male median lobe, ventral aspect, 16) male right lateral lobe, right lateral aspect. Scale bar 5 0.5 mm.