Hydrochus ampliarmus, 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 : 16-17

publication ID

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

publication LSID

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

DOI

https://doi.org/10.5281/zenodo.10532293

persistent identifier

https://treatment.plazi.org/id/03A187DE-FFF3-FFEF-6194-FBEA04B1F7D2

treatment provided by

Plazi

scientific name

Hydrochus ampliarmus
status

sp. nov.

Hydrochus ampliarmus View in CoL , new species

Figs. 3 View FIGURE 3 , 49 View FIGURES 48–49 , 57 View FIGURES 57–58 , 70 View FIGURE 70

Type Material. Holotype (male): “ BRAZIL: Rondonia, Machadinho d’Oeste, Balneário São José (-9.44573 - 61.98332), 103 m.; 9.vii.2018, leg. Short, margins of various places on river, BR18-0709-01A” ( INPA) GoogleMaps . Paratype: Same data as holotype (1 SEMC) GoogleMaps .

Differential Diagnosis. Among Brazilian species, recognized by the combination of small size (ca. 2.28 mm), black color, the sculptured dorsum, with deep foveae, raised elytral intervals, small callus of 5 th elytral interstria, and the male genitalia ( Fig. 49 View FIGURES 48–49 ; described below). Reliable differentiation from other similarly small sized black species with raised or costate elytra should include dissection of males.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 2.28/0.91; head width 0.59; pronotum l/w 0.54/0.58; PA 0.58; PB 0.46; elytra 1.45/0.91. Habitus as illustrated ( Fig. 49 View FIGURES 48–49 ). Dorsum black. Legs brown, lateral margin of tibiae with row of spines. Head with frons medially slightly tumid, with longitudinal punctate groove on each side of tumidity. Punctation on elytra ca. 3–5x that of pronotum. 5 th interstria raised, with usual callus, very small, low.

Pronotum slightly wider than long (ratio ca. 16/15), widest at anterior margin, strongly narrowed at base, sides weakly sinuate, non-denticulate; anterior margin bisinuate; lateral and anterior margins with row of moderately long setae; depressions large, deep, much more densely punctate than almost impunctate reliefs.

Elytra with intervals 3, 5, 7, and 9 very slightly raised, not costate; punctures large, spaces between strial punctures narrow walls to 1xpd, many punctures in off-set zig-zag pattern; apices acuminate, truncate apically in dorsal view, in lateral view outer margin without angulation.

Ventral characters: Mentum moderately coarsely and moderately densely punctate, with shallow median fovea. Submentum narrow, without foveae.

Male genitalia ( Fig. 49 View FIGURES 48–49 ) general characters: genitalia without parameres, basal piece elongate, trisinuate in lateral view, in dorsal/ventral views straight, slightly widened at ca. midlength and distal 3/4; distal end produced in microreticulate lobe on dorsal surface, ventral apex produced in short beak-like shape.

Etymology. Named in reference to the width of the elytra at the humeral angles.

Remarks. The holotype has dorsal encrustations, which defied removal. This adversely affected the habitus images.

INPA

Instituto Nacional de Pesquisas da Amazonia

SEMC

University of Kansas - Biodiversity Institute

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Hydrochidae

Genus

Hydrochus

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