Hydrochus merkli Makhan

Perkins, Philip D., 2021, Taxonomy of water beetles in the genus Hydrochus Leach, 1817, from Bolivia, Brazil and Paraguay (Coleoptera: Hydrochidae), Zootaxa 4994 (1), pp. 1-93: 46-47

publication ID

https://doi.org/10.11646/zootaxa.4994.1.1

publication LSID

lsid:zoobank.org:pub:107FCA64-345F-40A4-99D3-5C1441EEAD93

persistent identifier

http://treatment.plazi.org/id/03A187DE-FFD1-FFD1-6194-F8F305AAF04B

treatment provided by

Plazi

scientific name

Hydrochus merkli Makhan
status

new status

Hydrochus merkli Makhan   , new status

Figs. 2 View FIGURE 2 , 11 View FIGURES 10–11 , 56 View FIGURES 55–56

H. merkli Makhan, 1993: 67  

H. piroei Makhan, 1992   ; Oliva 1996; invalid synonymy by Oliva (1996) (see remarks)

Originally described from northern Argentina. New records from Argentina, Bolivia and Paraguay are given below.

Material examined (152): Argentina: Buenos Aires Province, Buenos Aires Parque , (34°36’13.32’’S, 58°22’53.76’’W), 1.i.1905, leg. no collector on label (1 MCZ) GoogleMaps   ; Monte Brown, W. Chascomus , (34°36’13.32’’S, 58°22’53.76’’W), 27–28.xi.1979, leg. C. M. & O. S. Flint (1 NMNH) GoogleMaps   ; Santiago del Estero, E. of Lapida, ponds along road Frias —Villa San Martin, elev. 200 m (28°22’55’’S, 64°31’36’’W), 24.ii.2004, leg. Beutel & Komarek (2 NMW) GoogleMaps   . Bolivia: Santa Cruz, 60 mi. N   . Santa Cruz, Saavedra Exp. Sta. , December 27–30, 1959, Robert Cumming ” (7 NMNH)   . Santa Cruz, Okinawa , 6.vi.1958, leg. E. Pinckert (6 CAS)   ; Santa Cruz, 2.7 m S of San Jose , elev. 333 m (17°52’20’’S, 60°44’28’’W), 27.vi.1999, leg. K. B. Miller (1 SEMC) GoogleMaps   ; Santa Cruz, (17°48’S, 63°11’W), 11–12.v.1969, leg. P. & P. Spangler (1 NMNH) GoogleMaps   . Paraguay: Alto Parana, [no other locality data] (25°36’27.36’’S, 54°57’40.32’’W), 16.xi.1990, leg. Pena (1 NMW) GoogleMaps   ; Dep. Boqueron, Mistolar , (23°13’S, 61°41’W), 3–12.x.1997, leg. Drechsel (95 NMW) GoogleMaps   ; Dep. Pte. Hayes, Puerto Galileo , (25°8’S, 57°50’W), 27–29.viii.2005, leg. U. Drechsel (16 NMW) GoogleMaps   ; same locality, 1–3.xi.2005, leg. U. Drechsel (17 NMW) GoogleMaps   ; Paraquari, P.N. Yvycul, Arroya Mina , 640 ft., (25°37’34.32’’S, 57°9’7.56’’W), 26.vi.2006, leg. W.D. Shepard (WDS-A-1700) (1 SEMC) GoogleMaps   ; South of Sapucai, 550 ft., Arroyo Cuazu Cua , (25°39’41.76’’S, 56°57’37.8’’W), 21.vi.2006, leg. W.D. Shepard (WDS-A-1693) (3 SEMC) GoogleMaps   .

Differential Diagnosis. Among Bolivian species, recognized by the combination of moderate size (ca. 2.90 mm), the moderately shallow pronotal depressions, the moderately low and relatively impunctate pronotal reliefs, and the male genitalia ( Fig. 11 View FIGURES 10–11 ; described below). This species has a generalized Hydrochus   habitus; reliable determinations will require dissection of males.

Description. Size (length/width, mm): body (length to elytral apices) 2.90/1.00; head width 0.68; pronotum l/w 0.66/0.63; PA 0.61; PB 0.55; elytra 1.84/0.99. Habitus as illustrated ( Fig. 11 View FIGURES 10–11 ). Dorsum grey, with moderately strong gold iridescence, elytra with black spots. Legs testaceous, with tibiofemoral joints slightly darker. Punctation on elytra ca. 2–3x that of pronotum. Elytra interstriae ca. 1–2x strial puncture diameter. Interstria 9 th more convex than others, overhanging 10 th interstria. Callus on usual area of 5 th interstria weakly raised, moderately long; 5 th also slightly widened and slightly raised over ca. 2 nd 1/5 of interstria length.

Pronotum length slightly less than width, widest at about anterior 1/3, narrowed at base, sides sinuate, smooth; anterior margin arcuate or very slightly bisinuate; depressions moderately deep, reliefs moderately raised, depressions more densely punctate than reliefs.

Elytra with spaces between strial punctures narrow ridges to ca. 0.5xpd; apices rather sharply conjointly round- ed in dorsal view, in lateral view outer margin with slight angulation; striae 1–3 each terminating in slightly larger, translucent puncture.

Ventral characters: Mentum punctate, with central depression; submentum with two small, circular, deep foveae.

Male genitalia ( Fig. 11 View FIGURES 10–11 ) general characters: genitalia narrow (l/w ratio ca. 47/8); paramere tips elongate, slightly widened, distal ends pointed, lateral margins straight from plsa to distal tip, medial margins of tips emarginate, distal end of tips extending slightly beyond aedeagus, in lateral view tips narrow, sharply pointed; aedeagus lanceolate in dorsal/ventral views, widest at ca. midlength, tapering to sharp distal end, with narrowly sclerotized lateral margins; basal piece slightly shorter than parameres (ratio ca. 23/25), tapering from distal end to slightly asymmetrical orifice, rim of orifice sclerotized.

Dorsal surface: adtl located at ca. midlength of aedeagus; pdmm narrowly overlapping alm over proximal 3/4, then slightly separated from alm where paramere tips begin; adbl moderately small, width equal to ca. ¼ width of genitalia at that level.

Ventral surface: pvmm very slightly overlapping alm at base; avtl at ca. proximal 1/6.

Remarks. Oliva (1996: 329) placed H. merkli Makhan, 1993   as a junior synonym of H. piroei Makhan, 1992   . I have examined the holotypes of both H. piroei (NBC)   and H. merkli (NBC)   , including the male genitalia, and find that they undoubtedly represent different species (see figures of H. piroei   in Perkins, 2019c, and H. merkli   herein). Consequently, the synonymy proposed by Oliva (1996), with H. merkli Makhan   as a junior synonym of H. piroei Makhan   , is invalid. The specimen imaged ( Fig. 11 View FIGURES 10–11 ) has the following locality data: Bolivia: Santa Cruz, 60 mi. N. Santa Cruz, Saavedra Exp. Sta.

MCZ

Museum of Comparative Zoology

NMNH

Smithsonian Institution, National Museum of Natural History

NMW

Naturhistorisches Museum, Wien

CAS

California Academy of Sciences

SEMC

University of Kansas - Biodiversity Institute

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Hydrochidae

Genus

Hydrochus

Loc

Hydrochus merkli Makhan

Perkins, Philip D. 2021
2021
Loc

H. merkli

Makhan, D. 1993: 67
1993