Hydraena (Hydraenopsis) bahiana, Benetti & Valladares & Delgado & Hamada, 2022

Benetti, Cesar J., Valladares, Luis F., Delgado, Juan A. & Hamada, Neusa, 2022, Hydraena bahiana sp. n., a new minute moss beetle (Coleoptera, Hydraenidae) from highlands of Northeast Brazil, Zootaxa 5128 (4), pp. 538-546 : 539-545

Hydraena (Hydraenopsis) bahiana sp. n.

( Figs 1–4 )

Type locality. BRAZIL, Bahia State, Abaíra County, Catolés, Serra do Barbado (13°17’24.0’’S, 041°54’21.5’’W) .

Type material. Holotype (male): “ BRAZIL: Bahia State, Abaíra County / Catolés, Serra do Barbado , pools, 1,705 m.a.s.l. / 13°17’24.0’’S; 041°54’21.5’’W; 26/ii/2018 / C. J. Benetti & A.E.Z. Short leg. // ♂ // HOLOTYPUS [red label] // Hydraena (Hydraenopsis) bahiana sp.n. ” (genitalia extracted and mounted on same card) ( INPA) . Paratypes: 2 females. Same data as holotype except: // ♀ // PARATYPUS [red label] (genitalia extracted and mounted on same card) ( INPA) .

Type depository. Instituto Nacional de Pesquisas da Amazônia , Manaus, Brazil

Description. Habitus as in Fig. 1 . Size: Holotype: Male BL 1.47 mm; EL 0.93 mm; EW 0.62 mm.

Color ( Fig. 1 ): Dorsum of head black, labrum dark brown with lateral sides yellowish; pronotum with disc dark brown and extensive lateral sides yellowish brown, scintilla black; elytra dark brown, lateral margins and apex yellowish brown. Antennae and maxillary palps testaceous, last palpomere with preapical area brown; legs testaceous. Both ventral surface and epipleura dark brown.

Head: Labrum scarcely punctured, with an open v-shaped apicomedian emargination and a median small projection, margins of lateral lobes convex. Clypeus rugose with large, sparsely arranged punctures each bearing a small white seta. Punctures on frons very broad, deep and adjoining, interstices between punctures convex and shiny.

Pronotum: Wider than long (PW 0.48 mm, PL 0.33 mm), maximum width slightly below mid length. Anterior margin clearly emarginate behind frons except at the convex scintilla margin, disc broadly and completely punctured. Scintilla distinct, deep, shiny, impunctate, with arcuate anterior and posterior margins. Lateral sides weakly convex, with margins strongly serrate. Posterior margin slightly convex. Discal punctures large, deep, similar in size and shape to those of marginal areas, interstices wide and shiny. PF1 absent, PF2 shallow deep, PF3 very wide, oval and moderately deep, PF4 absent.

Elytra: Arcuate laterally, with marked shoulders. Lateral explanate margins wide, obsolete at apex. With eight rows of rather regular impressed punctures between suture and shoulder; size of punctures similar to those of pronotum. Intervals wide, not raised, shiny. Apex rounded with a small sutural echancrure.

Mesoventrite: With internal and external carinae, posteriorly divergent; median carina extended to base of intercoxal process; intercoxal process moderately wide, apex blunt, with convex end.

Metaventrite: Plaques faintly marked, microreticulate, wide and straight, posterior margins connate; width of each plaque similar to that of distance between.

Legs: Protibiae slightly arcuate and expanded towards apex. Mesotibiae and metatibiae straight and slender.

Abdomen: Sternite X and spiculum gastrale as in Fig. 2 . Sternite X ( Fig. 3c ) subtriangular, distal end rounded, basal angles mucronate, markedly produced laterally, disc glabrous and irregularly bordered by a translucent lamina; spiculum gastrale long, parallel sided and firmly attached to sternite X; distal end of spiculum distinctly dilated, resembling the capitate stigma of a pistil ( Figs 2 a, b, d ).

Aedeagus as in Fig. 3 . Parameres of similar shape, strong and straight, both ended in a laminar, blade-shaped area ( Figs 3 a, c ). Left paramere shorter ( Figs 3 c, d ). Main piece in lateral view ( Fig. 3 b ) curved and wide, distinctly projected ventrally in a heel just at the area of insertions of parameres. Distal lobe with two major appendages: basal one broad, membranous and bearing the gonopore, distal one longest and, in ventral view ( Fig. 3 d ), abruptly constricted basally forming a narrow neck and a broadly subquadrate lobe at apex ( Fig. 3 d ).

Female: Size: Paratypes (n=2): BL 1.44–1.46 mm; EL 0.89–0.91 mm; EW 0.62–64 mm. Shape and color similar to male. Pronotum similar to male; PF1 absent, PF3 elongated, moderately deep, PF2 very shallow, PF4 absent. Protibiae with the outer edge very slightly curved, meso and metatibiae straight. Metaventral plaques more marked than the male studied.

Terminal abdominal segments and spermatheca: Terminal tergite ( Fig. 4d ) subelliptical. Disc covered by short setae and with distal margin slightly emarginated. Last abdominal ventrite ( Fig. 4c ) with two plates. Ventral plate semicircular, with two subapical tufts composed of three setae. Dorsal plate symmetrical, with a proximal central area pointed and bent to the right ( Fig. 4c ), distinctly surpassing the proximal rim of ventral plate. With two slightly impressed subelliptical depressions.

Spermatheca ( Figs 4 a, b ) long, curved and bell-shaped distally.

Differential diagnosis. The new species is a member of the Hydraena scintillabella subgroup of the leechi group. In this subgroup Perkins (2011) set aside a number of species with uncertain relationships. The new species should be placed in this provisional section. Externally, the scintillabella subgroup is quite variable in shape and coloration. Most of these species are medium sized and have a distinct scintilla ( Perkins 2011), which is very evident in H. bahiana sp. n. The new species resembles a group of three related species from Eastern Brazil (Minas Gerais State): Hydraena scintillutea Perkins, 1980 , H. alterra Perkins, 1980 and H. terralta Perkins, 1980 , whose members share a similar pronotal and aedeagal morphology. The pronotal fovea pattern is quite similar, with shallow or absent foveae except for the marked PF3 foveae. It differs from these three species by having a larger size, especially from the smaller H. alterra , which also lacks scintilla and metasternal plaques. From the other two, the new species also differs in the metasternal plaques, being shallow, wide, and straight in the new species, but narrow and convergent anteriorly in H. scintillutea and very small and oval in H. terralta . The general structure of the aedeagus in the scintillabella subgroup is rather constant, consisting in a broad main piece with a basal heel and distal lobe with two appendages of different shape: basal one plicate and bearing the gonopore and distal one more elongate. The aedeagus of the new species specially resembles to that of H. alterra and H. terralta but differs in having a more symmetrical, distinctly capitate distal lobe in ventral view. Externally it also differs from these two related species by having a wider and shiny scintilla.

Etymology. This species is named after the State of Bahia in Brazil, where the type locality is located. The name is in apposition in the adjective case.

Habitat ( Fig. 5 ). Specimens were collected in pools connected to the headwater stream named Forquilha, at 1,705 m above s.l., this stream belongs to the Rio de Contas drainage basin and is located in Serra do Barbado Environmental Protection Area (EPA), where Pico do Barbado, the highest point in the Northeast of Brazil (2,033m above s.l.) is located ( INEMA 2022). This mountain range is part of the Serra do Espinhaço, a wide mountain range running in north-south direction and extended through the east and northeast of Brazil. This EPA represents a transition zone between the Caatinga, Cerrado and the Atlantic Forest biomes, in addition to the presence of “campos rupestres” in the higher portions and has been identified as an important endemism center. “Serra do Barbado” is considered a priority area for biodiversity conservation ( Silva et al. 2008) and represents a true “cradle of springs” functioning as a watershed for different hydrographic basins, with a great profusion of springs sculpting the relief with waterfalls.

Distribution. Currently only known from the type locality in Bahia State, Brazil ( Fig. 6 ).

Figures

FIGURE 1. Hydraena bahiana sp. n., holotype male. Dorsal (a) and ventral (b) habitus. Scale bar = 0.5 mm.

FIGURE 2. Hydraena bahiana sp. n., holotype male. Sternite X (c) and Spiculum gastrale (a, b, d). Scale bar = 0.1 mm.

FIGURE 3. Hydraena bahiana sp. n., holotype male. Aedeagus in lateral (a, b) and ventral (c, d) view. Scale bar = 0.1 mm.

FIGURE 4. Hydraena bahiana sp. n., paratype female. Last abdominal segments and spermatheca. Spermatheca (a, b), last abdominal ventrite (c) and terminal tergite (d). Scale bar = 0.05 mm.

FIGURE 5. Habitat of Hydraena bahiana sp. n.. Pools at 1,705 m. altitude (a, b). General view of Serra do Barbado, Bahia State (c, d)

FIGURE 6. Map with type locality of Hydraena bahiana sp. n.. (red circle).