Berosus illuviosus, Santana & Benetti & Clarkson & Pes, 2019

Santana, Larissa, Benetti, Cesar João, Clarkson, Bruno & Pes, Ana Maria, 2019, On the genus Berosus Leach (Coleoptera: Hydrophilidae) in the State of Roraima Brazil: description of three new species and new records, Zootaxa 4700 (4), pp. 445-463 : 452-454

Berosus illuviosus sp. n.

( Figs. 5 a–h)

Type locality. BRAZIL: Roraima State, Boa Vista County (municipality), pond near the “ Estrada do Contorno ” road (02°46’00.4’’N / 60°45’38.0’’W) ( Fig. 3 )

Type material. Holotype male. BRAZIL: Roraima State, Boa Vista County (02°46’00.4’’N / 60°45’38.0’’W), 01.vi.2015, leg. K. Dias, C. Benetti. Condition of holotype: stored in 80% ethanol with the dissected male genitalia stored in microvials with glycerin, deposited at INPA . Paratypes (211). BRAZIL: Roraima State: Same data as holotype except [3 males and 15 females stored in 80% ethanol, deposited at INPA] ; same data as holotype except (02°47’29.8’’N / 60°47’08.4’’W) [17 males and 13 females stored in 80% ethanol, deposited at MZSP] ; same data as holotype except (02°46’23.8’’N / 60°45’41.8’’W) [12 males and 35 females stored in 80% ethanol, deposited at MNRJ] ; same data as holotype except (02°48’21.2’’N / 60°47’40.8’’W), 02.vi.2015 [11 males and 9 females stored in 80% ethanol, deposited at SEMC] ; same data as holotype except (02°52’06.4’’N / 60°51’57.9’’W), 03.vi.2015 [20 males and 33 females stored in 80% ethanol, deposited at DZUP]; except same data as holotype (02°49’17.4’’N / 60°48’10.6’’W), 06.vi.2015 [2 males and 2 females stored in 80% ethanol, deposited at INPA] ; same data as holotype except (02°51’46.3’’N / 60°47’30.6’’W), 07.vi.2015 [1 male and 16 females stored in 80% ethanol, deposited at INPA]; Alto Alegre County (02°49’17.4’’N / 60°48’10.6’’W), 06.vi.2015, leg. K. Dias, C. Benetti [5 males and 9 females stored in 80% ethanol, deposited at INPA]; Alto Alegre County (02°59’37.1’’N / 61°07’38.9’’W), 06.vi.2015 leg. K. Dias, C. Benetti [2 males and 6 females stored in 80% ethanol, deposited at INPA] .

Diagnosis. Berosus illuviosus sp. n. can be distinguished from other Neotropical species of Berosus by the following combination of characteristics: moderate size (4.30–4.40 mm); head, pronotum and elytra dark brown to black, without metallic luster ( Fig. 5a ); pronotum with coarse, round or polygonal punctures ( Fig. 5a ); elytral striae well-impressed with deep, rectangular punctures ca. 2–3× as large as those on the pronotum ( Fig. 5a ); mesoventral process strongly raised, with straight and hood-like anterior tooth, excavated in the center, with serrated margins ( Fig. 5d ); abdominal ventrites crenulate along lateral and posterior margins; first ventrite with a median longitudinal carina on anterior two-thirds; fifth ventrite with apical notch ca. one-fifth the total length, bearing two medial acute teeth ( Fig. 5e ).

Description. Size and form. Total length: 4.34–4.36 mm. Body short, nearly 2× longer than wide in dorsal view ( Fig. 5a ), strongly convex in lateral view ( Fig. 5b ).

Color. Labrum, clypeus and frons dark brown to black without metallic luster ( Fig. 5a ); maxillary palpi yellow with fourth palpomere dark brown, yellow at base ( Figs. 5 a–c); pronotum dark brown without metallic luster; scutellar shield dark brown ( Fig. 5a ); elytra completely dark brown ( Fig. 5a ); venter of thorax and abdomen dark brown to nearly black ( Fig. 5c ); femora with pubescent portion dark brown, glabrous portion yellow; tibiae yellow at base, posterior half dark brown; tarsus dark brown with apex and distal region yellow. ( Figs. 5 a–c).

Head. Clypeus and frons densely and coarsely punctate, punctures ca. 6–7× as large as ommatidia, round or polygonal in shape ( Fig. 5a ). Frontal carina absent. Eyes strongly prominent ( Fig. 5a ). Maxillary palpi short, nearly half as long as width of the head, and thick ( Figs. 5 a–c).

Thorax. Pronotum distinctly narrower than elytra, with coarse and dense punctures, at the same size as those on head, round or polygonal in shape ( Fig. 5a ). Scutellar shield coarsely punctate with punctures similar in size to those on pronotum. Elytral striae well-impressed with deep, rectangular punctures ca. 2–3× as larger as those on the pronotum; interstriae reduced to thin edges on elytral disc; humeral hump prominent ( Fig. 5a ); elytral apices rounded ( Figs. 5 a–c); spine-like hairs absent ( Fig. 5a ). Mesoventral process strongly raised, with straight and hood-like anterior tooth, excavated in the center with serrated margin; posterior angle of the mesoventral process rounded in lateral view, very shortly prominent, serrated ( Fig. 5d ). Metaventral process narrow; posterolateral angles not produced; posterior angle not raised ( Fig. 5c ). Basal pubescence on femora reduced, obliquely limited to the base ( Fig. 5c ). Protarsus of male without adhesive soles; first tarsomere ca. 1.5× longer than the second, fourth tarsomere elongate, almost as long as tarsomeres 1–3 combined ( Figs. 5a, c ). Claws weakly arched ( Figs. 5 a–c).

Abdomen. First ventrite with a median longitudinal carina along anterior two-thirds, without lateral depressions; abdominal ventrites 2–4 without central carina or teeth-like projection, crenulate along lateral and posterior margins; fifth ventrite with apical notch ca. one-fifth the total length, bearing two medial acute teeth ( Fig. 5e ). Aedeagus with basal piece ca. half of total length, 1.5× longer than its greatest width ( Figs. 5 f–h); parameres symmetrical, slightly longer than median lobe in dorsal view ( Fig. 5f ), gradually acuminate at apex; apical portion of parameres strongly curved towards ventral face, forming a nearly right angle with dorsal outline of aedeagus in lateral view ( Fig. 5g ), bearing a row of long hairs in the subapical concave portion ( Figs. 5g, h ); median lobe abruptly swollen subapically in dorsal view, apex strongly acuminate in lateral view, directed towards ventral face ( Figs. 5g, h ).

Etymology. The specific epithet, illuviosus , refers to the “dirty” appearance of the specimens of this species (From Latin “which cannot be washed”).

Distribution. Brazil (Roraima).

Biology. The specimens were collected in ponds with abundant macrophyte cover ( Figs. 1, 2 ).

Taxonomic comments. Berosus illuviosus sp. n. can be placed in the holdhausi -complex ( Oliva 1989; Oliva & Short 2012), based on the following characteristics: very coarse dorsal sculpture; elytra with humeral humps prominent and without spine-like hairs; abdominal ventrites medially carinate on most of first ventrite length, without lateral depressions; apical notch of fifth ventrite produced at the bottom into a pair of sharp teeth with lateral and posterior margins strongly crenulate; protarsus of males not strongly swollen at base and without soles of specialized adhesive hairs; male genitalia with aedeagus weakly compressed laterally, parameres parallel and acuminate, median lobe strongly curved and strongly swollen at apex. The species is similar to B. rectangulus Mouchamps, 1960 by the dorsal sculpture, size and shape of femoral pubescence and appearance of abdominal ventrites, but it is distinguished by the dorsal coloration, shape of the mesoventral process and male genitalia. Berosus illuviosus sp. n. has a dark brown to black dorsal coloration, without spots ( Fig. 5a ), while B. rectangulus has a yellow dorsal coloration with dark brown spots. In addition, these species can be differentiated by the anterior tooth of the mesoventral process which is stronger and straight with serrated margins in B. illuviosus sp. n. ( Fig. 5d ), while in B. rectangulus the anterior tooth is of laminar form with smooth margins, and by the shape of the parameres. In B. illuviosus sp. n. they have a more pronounced preapical curvature, forming a nearly right angle with dorsal outline of aedeagus in lateral view ( Fig. 5g ) while in B. rectangulus the parameres curl gradually, exhibiting a more discrete curve.

Figures

FIGURE 5. Berosus illuviosus sp. n. (A–C) Habitus, A) dorsal view; B) lateral view; C) ventral view; D) Mesoventral process, ventral view, E) Abdomen, ventral view; (F–H) Aedeagus, F) dorsal view; G) lateral view; H) ventral view.

FIGURES 1–3. Habitat and type locality of the Berosus new species: 1) Brazil: Roraima State: Boa Vista County, pond near the RR-205 road, 2) detail of the habitat. 3) Type locality of Berosus andreazzei sp. n. (triangle), Berosus illuviosus sp. n. (square) and Berosus parvus sp. n. (circle).