Hydrochus forcipulus, Perkins, 2021

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 : 27

publication ID

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

publication LSID

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

persistent identifier

https://treatment.plazi.org/id/03A187DE-FFE6-FFE5-6194-FF6707EEF252

treatment provided by

Plazi

scientific name

Hydrochus forcipulus
status

sp. nov.

Hydrochus forcipulus View in CoL , new species

Figs. 2 View FIGURE 2 , 36 View FIGURES 36–37 , 55 View FIGURES 55–56

Type Material. Holotype (male): “ BOLIVIA: Beni, 40 km E. San Borja, Estacion Biologica Beni, Estancia El Porvenir ; 6–8 Sept. 1987; W. E. Steiner // At black light; open grass savanna and marsh” ( NMNH) . Paratypes (2): Bolivia: Beni, 40 km E. San Borja, Estacion Biologica Beni, Palm Camp , (14°44’S, 66°40’W), 10.ix.1987, leg. M. G. Pogue (1 NMNH) GoogleMaps ; Beni Stn., Palm Camp, NE. of San Borja , 6–9.viii.1988, leg. Robert W. Brooks (1 NMNH)

Differential Diagnosis. Among Brazilian species, recognized by the combination of small size (ca. 1.95 mm), the grey to black color, the pronotum with very shallow impressions and coarse dense punctuation, the pronotal shape, and the male genitalia ( Fig. 36 View FIGURES 36–37 ; described below). Differentiation from other similarly small sized species with similarly shaped pronotum will require dissection of males.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.95/0.78; head width 0.53; pronotum l/w 0.50/0.49; PA 0.47; PB 0.43; elytra 1.27/0.78. Habitus as illustrated ( Fig. 36 View FIGURES 36–37 ). Body size small (ca. 2.36 mm). Dorsum grey, with moderately strong iridescence, elytra without black spots. Legs brown to testaceous, with tibiofemoral joints darker. Punctation on elytra ca. 1–2x that of pronotum. Elytra interstriae ca. 0.5–1x strial puncture diameter. Interstria 9 th more convex than others, overhanging 10 th interstria. Usual area of callus on 5 th not raised.

Pronotum slightly wider than long (as ca. 15/16), widest at anterior margin, markedly narrowed at base, sides very slightly arcuate, smooth; anterior margin bisinuate, with fringe of short setae over lateral 1/3; depressions very shallow; punctation coarse and dense.

Elytra with spaces between strial punctures narrow ridges 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 moderately coarsely punctate, median fovea shallow; submentum without foveae.

Male genitalia ( Fig. 36 View FIGURES 36–37 ) general characters: genitalia very narrow, elongate, length ca. 6x greatest width, parameres longer than basal piece (ratio ca. 19/15); parameres tapering to very fine apices, very narrow and extending well beyond distal end of aedeagus, medial margins beyond aedeagus tip diverging slightly one from the other, plsa absent, in dorsal/ventral views lateral margins of tips straight; in lateral view paramere tip very thin and arcuate ventrad, sharply pointed apically; aedeagus moderately wide, agw at ca. midlength; basal piece in dorsal/ventral views with slightly arcuate lateral margins, in lateral view arcuate, dorsal surface more arcuate than ventral, maximum width in dorsal/ventral views slightly greater than lateral width, orifice asymmetrical, margin sclerotized.

Dorsal surface: adtl at ca. midlength of aedeagus; pdmm slightly overlapping alm in proximal ½, otherwise approximating alm; adbl small.

Ventral surface: avtl at ca. midlength of aedeagus; pvmm overlapping alm in proximal 1/3, medial margins very narrowly separated.

Etymology. Named in reference to the forceps-like male genitalia.

NMNH

Smithsonian Institution, National Museum of Natural History

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Hydrochidae

Genus

Hydrochus

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