Taxonomy of Central American water beetles in the genus Hydrochus Leach, 1817 (Coleoptera: Hydrochidae) Author Perkins, Philip D. text Zootaxa 2021 2021-05-21 4974 3 459 503 journal article 6214 10.11646/zootaxa.4974.3.2 5b4eaeb3-5722-4021-84ad-125ccd80855f 1175-5326 4777839 1BD6220B-7540-4A12-B3D2-5EDC1A3B7DD8 Hydrochus brianbrowni Makhan Figs. 2 , 9 , 31 Hydrochus brianbrowni Makhan 2005: 63 . Originally described from southern Arizona. New locality data records for Mexico are given below Material examined (52): Mexico : Baja California , Arroyo Saltito nr. Las Cruces, E. of La Paz , 23.i.1959 , leg. H. B. Leech (1 CAS ) ; Baja California Sur , 9 mi. up Canyon San Bernardo fr. Boca de la Sierra ( Potrero ), elev. 457 m ( 23°23’N , 109°57’W ), 2.viii.1971 , leg. H. G. Real & R. E. Main (1 FSCA , 37 CAS ); Sa. Victoria , 7 mi. W Santiago , ( 23°28’N , 109°50’W ), 30-31.x.1968 , leg. E. L. Sleeper & F. J. Moore (1 CAS ) ; Jalisco , Mpio. Tomatlán , Cajón de Peñas , 120 m , 15.vi.1994 , G. Nogueira col. (1 IEXA ) ; Quintana Roo , Pto . Morelos , 29.iv.1982 , leg. O. Comul (1 UNAM ) ; San Luis Potosi , 2 mi. S. San Luis Potosi , 21.xi.1948 , leg. H. B. Leech (1 CAS ) ; Sinaloa , Los Mochis , 8.vii.1922 , leg. C.T. Dodds (1 CAS ) ; Sonora , 20 mi. W. Moctezuma , 28.ix.1980 , leg. no collector on label (2 NMNH ) ; 7 mi. SE Alamos , 27.xi.1971 , leg. K. Stephan (2 NMNH ) ; La Pintada , 6.xi.1986 , leg. F. Arias (3 UNAM ) ; Zacatecas , Teul de Gonzalez Ortega , Huitzila ; borde arroyo, elev. 1718 m ( 21°36’46.1’’N , 103°36’22.2’’W ), 31.i.2004 , leg. V.Gomez & J.L. Navarrete-Heredia (1 NMNH ) . Differential diagnosis. Among Central American species, recognized by the combination of moderate size (ca. 2.94 mm ), the deep pronotal depressions, and the male genitalia ( Fig. 9 ; described below). This species has a generalized Hydrochus habitus; reliable determinations will require dissection of males. The aedeagus is very narrow, for comparison refer to the diagnosis of H. nayaritensis n. sp. Male genitalia ( Fig. 9 ). General characters: paramere tips slender and pointed, narrower in lateral view than in dorsal/ventral views, in dorsal/ventral views with medial margins at apex parallel or nearly so, then arcuate away from midline, slightly narrowed proximal to plsa; aedeagus in dorsal/ventral views very slender, parallel-sided or nearly so for entire length, apex pointed; in lateral view wider at base and slightly wider for remainder of length; lateral margins of aedeagus sclerotized; basal piece in dorsal/ventral views tapering from distal to proximal, in lateral view slightly wider proximally than distally, shorter than parameres, orifice strongly sclerotized. Dorsal surface: pdmm widely separated, overlapping aedeagus only very slightly at base; adbl moderately large; adtl at about distal 1/6; each paramere with prominent pwsa; paramere tips without sclerotized ridge. Ventral surface: pvmm well separated, except narrowly separated where overlapping aedeagus basally; avtl not apparent. Remarks. I have examined the holotype , including the male genitalia (LANHM). The specimen imaged ( Fig. 9 ) was collected at this locality: Baja California Sur , 9 mi. up Canyon San Bernardo fr. Boca de la Sierra (Potrero).