Hydrochus beeneni Makhan, 2021

Perkins, Philip D., 2021, Taxonomy of Central American water beetles in the genus Hydrochus Leach, 1817 (Coleoptera: Hydrochidae), Zootaxa 4974 (3), pp. 459-503 : 471-472

Hydrochus beeneni Makhan , new status

Figs. 2 , 21, 22 , 24 , 40

Hydrochus beeneni Makhan 1992: 100

Hydrochus piroei Makhan 1992 ; Oliva (1996) misidentification (see remarks)

Originally described from the Cayman Islands. This is a very commonly collected Central American species; all eight countries are represented in the specimen locality data records given below.

Differential diagnosis. Among Central American species, recognized by the combination of moderate size (ca. 2.76 mm), the densely punctate pronotum, the large and deep anteromedian pronotal fovea, the closely spaced serial elytral punctures, and the male genitalia ( Figs. 10–12 ; described below). This very common species has a generalized Hydrochus habitus; reliable determinations will require dissection of males. Refer also to the differential diagnosis of H. biexcavatus n. sp.

Redescription. Habitus as illustrated ( Figs. 21, 22 ). Size: Ca. (length/width, mm): body (length to elytral apices) 2.76/1.04; head width 0.64; pronotum l/w 0.62/0.64; PA 0.64; PB 0.56; elytra 1.76/1.04. Body size moderate (ca. 2.76 mm). Dorsum grey to greenish bronze, with strong to moderately strong iridescence, especially in anteromedian fovea of pronotum, elytra with large black spots. Punctation on elytra ca. 2–3x that of pronotum. Elytra interstriae ca. 1–1.5× strial puncture diameter. Interstria 9 th more convex than others, overhanging 10 th interstria. Usual area of callus on 5 th weakly raised, moderately elongate, ca. 7 punctures in row on each side.

Pronotum slightly wider than long, widest slightly behind anterior margin, narrowed at base, sides arcuate, smooth; anterior margin slightly bisinuate; rather uniformly densely punctate, except less dense in anteromedian fovea; depressions moderately deep, anteromedian deepest.

Elytra with spaces between strial punctures narrow walls to ca. 0.5x their diameter; apices rather sharply conjointly rounded in dorsal view, in lateral view outer margin with slight angulation.

Ventral characters: Mentum densely punctate, with median fovea. Submentum with two foveae. Legs testaceous, femora darker than tibiae.

Male genitalia ( Figs. 21, 22 , 24 ) general characters: paramere tips slender and pointed, much 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; aedeagus slender in dorsal and ventral views; in lateral view slightly wider; lateral margins of aedeagus sclerotized; basal piece shorter than parameres, orifice strongly sclerotized.

Dorsal surface: pdmm proximal to paramere tips parallel or nearly so, overlapping margin of aedeagus; adbl large; adtl near distal end; each paramere with sclerotized ridge as illustrated ( Figs. 10 , 11 ).

Ventral surface: pvmm more widely separated than pdmm, approximating lateral margin of aedeagus.

Material examined (258): Belize: Stann Creek, Kendal; ex side pool of Sittee River at bridge, 1.v.1987, leg. Spangler & Faitoute (7 NMNH) ; Stann Creek, Sittee Point; Possum Point Biol . Sta., 23.iv.1987, leg. P. J. Spangler & R. A. Faitoute (25 NMNH) ; same locality, 24.iv.1987, leg. P. J. Spangler & R. A. Faitoute (10 NMNH) ; same locality, 25.iv.1987, leg. P. J. Spangler & R. A. Faitoute (2 NMNH) ; Stann Creek, Sittee Point; Sittee River , 8 km upstream from Possum Point Biol. Sta., 22.iv.1987, leg. Spangler & Faitoute (54 NMNH) ; Belize Dist., Hattieville , 7-8.vii.1968, leg. W. L. Hasse (1 CNC, 2 NMNH) ; Cayo, Western Highway Mile 66, 5.vii.1969, leg. W. & D. Hasse (6 NMNH) ; Orange Walk Dist., Rio Bravo Pres. , black lights, 1.i.1996, leg. W. D. Shepard (3 NMW) . Costa Rica: Port Limon, 9.v.1929, leg. Darlingon (1 MCZ) ; Alajuela, Cano Negro , 24.viii.1998, leg. Drechsel (2 NMW) ; Puntarenas, Roadside pools; 7.9 km SE of La Palma; Osa Pensla. , elev. 34 m (8°36.07’N, 83°25.95’W), 18.vi.2003, leg. A. E. Z. Short (1 SEMC) . El Salvador: Zacatecoluca , 1.viii.1965, leg. Paul J. Spangler (1 NMNH) . Guatemala: Izabal, Finca Bello Horizonte ca 8 km SE of Rio Dulce, elev. 43 m (15°35’33.07’’N, 88°56’37.18’’W), 11.iii.2017, leg. R. S. Zack (5 WSU) ; Peten, Parque National Ixpanpajul, Rt. CA-13, near Santa Ana , elev. 188 m (16°52.439’N, 89°48.652 ’), 11.ix.2009, leg. R. S. Zack (3 WSU) ; Parque National Yaxha , ENE El Remate, elev. 167 m (17°4’1.99’’N, 89°24’.72’’W), 13.iii.2017, leg. R. S. Zack (13 WSU) . Honduras: Corozal Town , 29.viii.1967, leg. G. & R. Lacy (2 NMNH) ; San Marcus Colon, 28.vii.1965, leg. Paul J. Spangler (1 NMNH) ; Cortes, 24 mi. S. San Pedro Sula, 19.vi.1974, leg. M. E. and P. D. Perkins (1 MCZ) ; La Lima, 3.vi.1964, leg. Blanton, Broce, & Woodruff (23 NMNH) . Mexico: Campeche, 21 mi. E . Campeche, 27.vii.1964, leg. Paul J. Spangler (5 NMNH) ; Escarcega , 18.v.1962, leg. F. Islas S. (4 NMNH) ; Chiapas, 3 mi. N. Tapilula, 27.v.1974, leg. M. E. & P. D. Perkins (1 SEMC) ; Nayarit, San Blas, 12-14.vii.1960, leg. R. B. Loomis, J. Maris (5 CAS) ; same locality, 14.vii.1960, leg. R. B. Loomis, J. Maris (1 MCZ) ; Oaxaca, Tapanatepec , 23.viii.1965, leg. P. J. Spangler (1 NMNH) ; Quintana Roo, Km 146 carr Chetumal - Cancun , 3.v.1982, leg. V. Melendez (1 UNAM) ; Sonora, Cd. Obregon, 9.viii.1960, leg. W. W. Gibson (2 MCZ) ; Tabasco, 23 mi. N. Villahermosa, 6.viii.1964, leg. Paul J. Spangler (34 NMNH) ; Frontera , 23.vi.1969, leg. Bright & Campbell (1 NMNH) ; Mpio. Cdentla Rio Gonzalez Est. 4 Lagura Juliva , (18°20.757’N, 92°58.213’W), 27.iii.1998, leg. Bueno, Barba (1 UNAM) ; Rio Carrizal 2nd Secc. Rancheria Platanos ( Estanque ), 10.vi.1996, leg. J. Bueno, A. Contreres, R. Barba (1 UNAM) ; Rio Carrizal Desv. Reforma Km 234, 8.vi.1996, leg. J. Bueno, A. Contreres, R. Barba (7 UNAM) ; Rio Carrizal Est. No. 5, (17°58.21’N, 93°8.65’W), 10.vi.1996, leg. J. Bueno, A. Contreres, R. Barba (1 UNAM) ; Rio Samaria, Est. 4 (estanque), (18°.78’N, 93°4.75’W), 13.vi.1996, leg. Bueno, Santiago, Barba, Contreras (1 UNAM) ; Teapa , 25.v.1974, leg. M. E. & P. D. Perkins (12 MCZ) ; Villahermosa , 25.vii.1964, leg. Paul J. Spangler (1 NMNH) ; Veracruz, 25 mi. S. Acayucan, 4.vii.1965, leg. Paul J. Spangler (1 NMNH) ; 8 Mi. NE Panuco , 28.viii.1965, leg. P. J. Spangler (2 NMNH) ; Acayucan , 4.vii.1965, leg. Paul J. Spangler (1 NMNH) ; Sn. Jose Las Choapas Est. 7 Rio Tonala (vias del tren), (17°52.288’N, 94°5.042 ’), 24.iii.1998, leg. J. Bueno, R. Barba (1 UNAM) . Nicaragua: Carazo, Rio Casares , elev. 110 m (11°42’57.3’’N, 86°13’6.97’’W), 12.i.2013, leg. M. Brojer (1 NMW) ; Matagalpa, Matagalpa, km 77.6 Panam Highway, Rdside pool, elev. 393 m, 4.viii.2002, leg. W. D. Shepard (2 SEMC) ; Rio San Juan, 60 km SE San Carlos, Refugio Bartola , ex. mercury vapor/UV light, elev. 100 m (10°58.4’N, 84°20.3’W), 30.v.2002, leg. R. Brooks, Z. Falin, S. Chatzimanolis (5 SEMC) ; Rivas, Res Sil Pr Domitila, UV lights, elev. 122 m, 5-9.vi.2005, leg. W. D. Shepard (1 SEMC) . Panama: Bocas del Toro, nr. Miramar , car-net between -82.30/+8.95 -81.19/+9.04, 24.vii.2014, leg. T. Struyve (1 HMNH) .

Male genitalia ( Figs. 21, 22 ). General characters: paramere tips slender and pointed, much 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; aedeagus slender in dorsal and ventral views; in lateral view slightly wider, dorsal surface with angulation where adbl and shaft join; lateral margins of aedeagus sclerotized; basal piece shorter than parameres, orifice strongly sclerotized.

Dorsal surface: pdmm proximal to paramere tips parallel or nearly so, overlapping margin of aedeagus; adbl large; adtl near distal end; each paramere with sclerotized ridge as illustrated ( Fig. 10 ).

Ventral surface: pvmm more widely separated than pdmm, approximating lateral margin of aedeagus.

Remarks. Oliva (1996) synonymized H. beeneni Makhan with H. piroei Makhan. This proposed synonymy is incorrect. I have examined the holotype, including the holotype male genitalia of H. beeneni (RBINS) . The male genitalia of the two species distinctly differ; see figure and detailed description of H. piroei male genitalia in Perkins (2019c). When the holotype specimen of H. beeneni was received, the male genitalia was in multiple pieces; these pieces are illustrated herein ( Fig. 24 ), and the dorsal habitus of the holotype is also illustrated. The male genitalia illustration in Makhan (1992) is oversimplified, only in one view, misleading, and of little diagnostic value. The specimens imaged herein have the following locality data: ( Fig. 21 ) Veracruz, 25 mi. S. Acayucan, 4.vii.1965, leg. Paul J. Spangler; ( Fig. 22 ) Bocas del Toro, nr. Miramar, car-net between -82.30/+8.95 -81.19/+9.04, 24.vii.2014, leg. T. Struyve.

Figures

FIGURE 2. Dorsal habitus of Central American Hydrochus species.

FIGURES 21–22. Habitus and male genitalia. 21. Hydrochus beeneni Makhan, non-type Panama. 22. Hydrochus beeneni Makhan, non-type Mexico.

FIGURES 23–24. Habitus and male genitalia of holotypes. 23. Hydrochus vanvondeli Makhan. 24. Hydrochus beeneni Makhan.

FIGURES 40–42. Geographical distribution maps.

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

FIGURES 11–12. Habitus and male genitalia of holotypes. 11. Hydrochus perpunctatus n. sp. 12. Hydrochus panamensis n. sp.