Helobata amazonensis Clarkson

Clarkson, Bruno & Almeida, Lúcia M., 2018, On Brazilian Helobata Bergroth, 1888 (Coleoptera: Hydrophilidae) II: new distribution data, Papéis Avulsos de Zoologia 58, pp. 1-6 : 2-5

Helobata amazonensis Clarkson ,

Santos & Ferreira-Jr., 2016 ( Figs. 7-8 )

Material examined: BRAZIL: Roraima State: Pacaraima Municipality: “Surumu, Roraima / IX.1966 / M. Alvarenga &/ F.M. Oliveira col.// Helobata amazonensis / Clarkson et al., 2016/ Clarkson det. 2018” (1 female: MZSP).

Distribution: Brazil ( Fig. 12 ): Amazonas and Roraima (new record) States.

Discussion: This species was described based on a single male specimen from Central Amazon. This is the first mention of a female specimen. The examined specimen corresponds to H. amazonensis by the moderate-size – 5.00 mm in length compared to 5.70 mm in the holotype; the coloration – dorsum yellow with conspicuous brown areas,pronotum with well-defined central brown area,elytra with faint light brown spots close to humeral humps and diffusely spread throughout elytral disc ( Fig. 7 ), and abdominal ventrites yellow ( Fig. 8 ); the general morphology of head and mouth parts – anterior clypeal margin convex, slightly truncate medially ( Figs. 7-8 ); frontoclypeal suture distinct ( Fig. 7 ); maxillary palpomere 3 and 4 subequal in length ( Fig. 8 ); mentum without conspicuous microsculpture; the general dorsal sculpture – punctures on elytral rows fine, regularly spaced ( Fig. 7 ); the presence of fine and very short decumbent setae distributed on anterior half of the clypeus; the general morphology of the ventral projections – posteromedial elevation on mesoventrite semi-trapezoidal, very wide, with strongly raised lateral carinae, oblique, widely distant each other, converging anteriorly; widely connected with the metaventral projection ( Fig. 8 ); metaventral projection (between mesocoxae) forming an elevated longitudinal carina, strongly and widely connected posteriorly with metaventral medial carina; metaventral medial carina rising gradually until connecting to metaventral projection ( Fig. 8 ).

In comparison with the holotype the examined specimen ( Fig. 7-8 ) shows variations in dorsal coloration as brown area on elytra expanded and elytral disc, head and pronotum without metallic sheen (with weak metallic sheen in the holotype); in the dorsal microsculpture as clypeal disc and frons with shagreened microsculpture on interstices of ground punctuation (without conspicuous microsculpture in the holotype); and in the presence of fine and very short decumbent setae on frons (absent in the holotype).

Figures

Figure 12. Updated distribution map of the Helobata Bergroth species in Brazil based on Fernández & Bachmann(1987),Clarkson et al.(2016) and the current work.

Figures 7-11. (7-8) Helobata amazonensis Clarkson,Santos & Ferreira-Jr. Habitus, (7) dorsal view, (8) ventral view, scale = 2.0 mm; (9-11) Helobata sp. Habitus, (9) dorsal view,(10) ventral view,scale = 2.0 mm;abdominal ventrites,(11) ventral view,scale = 1.0 mm.