Hydrochus brianbrowni Makhan

Perkins, Philip D., 2021, Taxonomy of Central American water beetles in the genus Hydrochus Leach, 1817 (Coleoptera: Hydrochidae), Zootaxa 4974 (3), pp. 459-503 : 473-474

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).

Figures

FIGURE 2. Dorsal habitus of Central American Hydrochus species.

FIGURES 9–10. Habitus and male genitalia. 9. Hydrochus brianbrowni Makhan. 10. Hydrochus nayaritensis n. sp. holotype.

FIGURES 31–33. Geographical distribution maps.