Hydroscapha natans LeConte, 1874

Maier, Crystal A., Ivie, Michael A., Johnson, James B. & Maddison, David R., 2010, A New Northern-Most Record for the Family Hydroscaphidae (Coleoptera: Myxophaga), with Description of a New Nearctic Species, The Coleopterists Bulletin 64 (4), pp. 289-302 : 296-297

Hydroscapha natans LeConte, 1874

Material Examined. CALIFORNIA: Contra Costa Co.; Arroyo Mocho ; 10 OCT 1975; J.B. Johnson colr. (37 MAIC); 20 SEPT 1976 (1 JBJC); 20 OCT 1979 (2 JBJC); 2 SEPT 1980 (1 JBJC) ; CALIFORNIA: Contra Costa Co.: 3 mi. S. Alam Co. Mines Rd.; 20 SEPT 1976; J. B. Johnson (1 JBJC) .

Hydroscapha natans was described from “Los Angeles, in the river” (LeConte 1874). Reichardt and Hinton (1976) considered the alate populations from the southern parts of the US to be the normal form of H. natans and the brachypterous Hot Creek Falls population to belong to the species, but different from the typical form. The types have not been studied, but we follow Reichardt and Hinton’ s interpretation of the species, except that we do not accept their inclusion of the Hot Creek Falls populations as belonging to H. natans . A revision is required to reevaluate the correct status of the alate populations, but this is beyond the scope of this work. The alate form, here considered H. natans sensu stricto ( Figs. 19A–C ), can be immediately distinguished from all other US populations we suspect of belonging to other species, except for Hydroscapha sp. from Amargosa Hot Springs ( Fig. 19D ) in Nevada, by the long metaventrite ( Fig. 6 ) and fully developed wings. Also, no other US species shares the combination of a short, curved tentorial bridge with tentorial arms inserted close to each other ( Fig. 17 ) and a wide disc of the mesoventrite (1.8× wide as long) ( Fig. 4 ).

POPULATIONS NOT ASSIGNED TO SPECIES

Figures

Fig. 19. Diversity in Hydroscapha populations in the United States: A) H. natans, Arizona, Santa Cruz Co., B) H. natans, California, Arroyo Mocho, C) H. natans, California, Alameda Co., D) Hydroscapha sp., Nevada, Amargosa Hot Springs, E) Hydroscapha sp., Idaho, Hot Creek Falls, F) Hydroscapha sp., Idaho, Sunbeam Hot Springs, G) H. redfordi, Idaho, Jerry Johnson Hot Springs, H) H. redfordi, Idaho, Weir Hot Springs.

Figs. 3–8. Hydroscapha spp. Disc of mesoventrites. 3) H. redfordi, disc of mesoventrite; 4) H. natans, disc of mesoventrite; 5) H. redfordi, metaventrite; 6) H. natans, metaventrite; 7) H. redfordi, male abdominal tergite VIII; 8) H. natans, male abdominal tergite VIII.

Figs. 16–17. Tentoria. 16) Hydroscapha redfordi; 17) Hydroscapha natans.