Berosus spiniger, Queney, Pierre, 2010

Queney, Pierre, 2010, Two new species of Berosus Leach from Brazil (Coleoptera: Hydrophilidae: Berosini), Zootaxa 2506, pp. 51-58 : 55-58

Berosus spiniger sp. n.

( Figs. 2 , 7 , 8–11 )

Type material. Holotype (male): " Brazil: Brasilia,/ Distrito Federal, 1138 m,/ III.1999,/ 15°45'35.99''S, 47°55'11.19''W,/ N. Dégallier leg." ( DZUP).

Diagnosis. Within the auriceps -complex, Berosus spiniger sp. n. combines a mesosternal process entirely laminar ( Fig. 8 ), black spots without metallic sheen on pronotum disc on both sides of a median testaceous band, micropunctures very rare on interstriae, femoral pubescence obliquely limited and rather extensive ( Fig. 10 ), male genitalia with distal part beyond basal piece narrow in ventral and dorsal aspect, basal piece representing about 60% of their total length, parameres ending in two narrow and parallel apices ( Fig. 7 b,c).

Description. Holotype (male). Total body length: 6.6 mm (fully extended); maximal width: 3 mm (at metacoxae level); humeral width: 2.4 mm; maximal height: 2.2 mm (at metacoxae level); length (body not extended)/height: 2.7; length/maximal width-humeral width: 11.

Body and form. General body form ( Fig. 2 ) rather elongated and convex, with elytra weakly widened and pronotum rather narrow. Head entirely metallic and shiny bronze green. Pronotum and elytra basically testaceous and rather shiny, without metallic sheen, with several black areas: on pronotum disc narrowly on both sides of a median testaceous band, on elytra with indistinct spots distributed along a broad V-shaped basal band, a median band and an apical band. Suture, scutellum, striae except 10th, elytral and pronotal punctures (the latter on disc) also blackened. Ground punctures on head and pronotum rather uniform-sized but irregularly spaced in some places, fairly dense (spaced by 1–2 times their diameter), a little finer on clypeus than on frons, concealed on labrum under a thick fringe of long pale hairs. Besides the main punctures there are rather uniform micropunctures. A narrow, nearly impunctate band on pronotal median line.

Head. Frons with a very fine longitudinal median carina. Maxillary palpi testaceous. Eyes rather prominent, ocular index OI = 2,4.

Thorax. Pronotum with lateral angles rounded, the posterior ones more broadly so. Scutellum punctate. Elytra with ten fine striae, all well impressed, with the inner ones more deeply impressed than the outer ones, their punctures spaced by 1 to 2.5 times their own width, more closely set along the inner striae. Punctures along inner striae subequal in size to those on pronotum, the punctures becoming larger on the outer striae. Interstriae wide and almost flat, with punctures rather fine and dense, forming somewhat irregular rows, sometimes two or three in number, as large as those of first inner striae. Punctures on interstriae largely absent on apical part. Micropunctures very rare and only on inner interstriae. Scutellar stria with about twenty punctures. Systematic punctures not larger on interstriae 3rd, 5th and 7th but bearing long hairs on apical area. Short spine-like hairs on apical third of outer elytral edge. Long hairs on interstria 11th. Sutural angle of each elytron narrowly rounded. Ventral surface glossy and pubescent, mostly punctate, blackened except prosternum testaceous. Mesosternal process laminar with a rounded tooth, behind this an irregular, not very depressed ridge ( Fig. 8 ). Metasternal process ( Fig. 9 ) triangular, narrowed backwards, with the postero-lateral angles strongly raised, produced and rounded, under abundant hairs, the posterior angle carinate and lower than postero-lateral angles. Legs testaceous except pubescent and blackish part of femora. Femoral pubescence obliquely limited and covering about 52% of the hind and 44% of the middle femora ( Fig. 10 ). Male protarsi a little modified with the first basal segment widened and bearing expanded pad. Claws fine and very long, curved and toothed at base.

Diagnostic characters aulus auriceps ethmonotus spiniger

Species O r c h y m o n t, Boheman, 1859 Oliva, 1989 Queney, sp. n. 1941

Length in mm 5.7 5–6.7 5.1–6.6 6.6 Pronotum: large medial spot, generally with metallic X

sheen

Abdomen. Lateral edges of ventrites evenly serrate. First ventrite without lateral depressions, with median carina on anterior half. Fifth ventrite with an apical notch, the lateral edges of which are not convergent, bottom produced into a tooth with a bidentate apex ( Fig. 11 ). Male genitalia ( Fig. 7 ) subcylindrical and thick, ventral face somewhat concave and dorsal face strongly convex in lateral aspect ( Fig. 7 a), distal part beyond basal piece very narrow in dorsal and ventral aspect. Total length: 1.6 mm, basal piece representing about 60% of it. Parameres broad at base in lateral aspect, strongly and evenly narrowed, with apex curved towards ventral face ( Fig. 7 a). Median lobe much shorter than parameres, bent towards dorsal face which it overlaps with its turned-up apex ( Fig. 7 a). In dorsal and ventral aspects, parameres rounded up inwards, ending in two narrow and parallel apices.

Discussion. As shown in Table 2, examination of male genitalia allows B. spiniger sp.n. to be easily distinguished from the three other species already known within the auriceps -complex. The basal piece of B. aulus Orchymont, 1941 and B. ethmonotus Oliva, 1989 is short and represents less than 45% of total length against nearly 60% in B. spiniger and B. auriceps Boheman, 1859 . In lateral aspect the parameres are not very different in the last two species but, in dorsal aspect, they are quite distinctive: in B. auriceps they narrow gradually towards the apex and curve regularly inwards while in B. spiniger ( Fig. 7 b) the curved outline is interrupted by an emargination before the apex, with the apices parallel. Other differential characters include: the shape of anterior tooth of mesosternal process (swollen in B. auriceps , laminar in the other species), elytral micropunctures well apparent in B. aulus and B. ethmonotus but not in B. auriceps and B. spiniger , extent of femoral pubescence, larger in B. spiniger than in B. auriceps and B. ethmonotus , and color of the pronotum of B. Spiniger without the metallic sheen of B. aulus .

Etymology. Named for the spine-like hairs on apical third of outer elytral edge.

Distribution. This species is only known from Brasilia ( Brazil) where it was collected at a light trap in "Cerrado".

Figures

FIGURE 7. Male genitalia of Berosus spiniger (1.6 mm long). a) lateral aspect; b) dorsal aspect; c) ventral aspect.

FIGURES 1 – 2. Dorsal habitus: 1) Berosus degallieri (3.3 mm long); 2) Berosus spiniger (6.6 mm long).

FIGURE 8 – 11. Ventral details of Berosus spiniger. 8) Mesosternal process; 9) Meso- and metasternal processes; 10) Meso- and metafemora; 11) Fifth ventrite.