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

Abstract Ereboporus naturaconservatus Miller, Gibson and Alarie, new genus and new species (Coleoptera: Dytiscidae) is described from specimens collected from Caroline Springs, Independence Creek, Terrel County, Texas, U.S.A. Specimens were collected using drift nets placed at the head of the spring, suggesting the species is subterranean and occurs in nearby areas of the Edwards-Trinity Aquifer. In addition, the new taxon is characteristic of subterranean diving beetles in having adults depigmented, relatively soft, and lacking metathoracic wings and compound eyes. In addition, the taxon is diagnosed among all adult Dytiscidae in having: 1) the head extremely large relative to the rest of the body, 2) the pronotum short and cordate; 3) the prosternal process small, short and not extending to the mesosternum; 4) the elytra fused along the suture; 5) the elytron and elytral epipleuron extending ventromedially, concealing large lateral portions of the abdominal sterna; 6) the female internal genitalia with a large, elongate, ring-shaped structure on the bursa. The species is placed in the tribe Hydroporini (Hydroporinae) based on the character states: 1) pro- and mesotarsi pseudotetramerous; 2) male genitalia bilaterally symmetrical; 3) scutellum not visible with the elytra closed; 4) prosternum in lateral aspect declivous; 5) metatarsal claws the same length; 6) apices of elytra evenly rounded; 7) metepisternum extending to mesocoxal cavity externally; 8) male lateral lobe with one segment; 9) metacoxal process with well-developed lobes; 10) anterior margin of metafemur distinctly separated from the lobes of the metacoxal process. Three additional subterranean species are known from North America, Comaldessus stygius Spangler and Barr, 1995, Stygoporus oregonensis Larson and Labonte, 1994, and Haideoporus texanus Young and Longley, 1976. Each of these species is figured and discussed.