Suphisellus grossoi, Urcola & Benetti & Baca & Michat, 2020

Urcola, Juan I., Benetti, Cesar J., Baca, Stephen M. & Michat, Mariano C., 2020, Suphisellus grossoi sp. n., a new burrowing water beetle from South America and notes on S. flavolineatus (Régimbart, 1889) and S. grammicus (Sharp, 1882) (Coleoptera: Noteridae), Zootaxa 4786 (1), pp. 122-130 : 123-125

Suphisellus grossoi sp. n.

( Figs 1–4 , 7–10 , 11 )

Type locality: Paraguay, Canindeyú Department, Reserva Natural del Bosque de Mbaracayú , 24°07’S, 55°26’W, elevation 232 m a.s.l.

Type material. HOLOTYPE: m*, labelled: “ PARAGUAY: Canindeyú Department / Reserva Natural del Bosque de Mbaracayú / 14.XII.2003, col.: O. Di Iorio. ” [typed, white label] “ HOLOTYPE / Suphisellus grossoi / Urcola et al. 2020” [typed, red label] (MACN-En 34702) . Paratypes: 4 m *, same data as holotype (MACN-En 34703 to 34706). All paratypes with the following label: “ PARATYPE / Suphisellus grossoi / Urcola et al. 2020” [typed, yellow label] .

Diagnosis. Total length = 2.4–2.6 mm. Background color brownish-red, elytra with diffuse pattern of longitudinal dark bands ( Figs 1, 3 ); pronotum without punctation, elytra with weak punctation; prosternum with 4–5 stiff setae on each side of middle, surrounded by several smaller setae ( Figs 2 , 4 ); prosternal process with apex relatively broad, with truncate slightly convex posterior margin ( Fig. 4 ). Male genitalia as in Figs 7–11 , median lobe ( Figs 10–11 ) in lateral view broadest at about basal third, then narrowing up to distal two thirds, distal third about parallel sided, apex rounded; base comprised of small lateral notches and a medial hook-like process.

Description of the holotype. Small beetle, TL 2.5 mm; body oval, dorsum moderately convex, broadest near base of elytra and posteriorly attenuated with narrowly≅ rounded apex, lateral margin continuous between pronotum and elytron ( Figs 1–3 ).

Color ( Figs 1–3 ). Background color brownish-red; head with two diffuse, subtriangular, darker spots between eyes; anterior margin of pronotum with series of semicircular dark spots; each elytron with five longitudinal dark bands, first band contiguous to suture, giving aspect to be shared by both elytra, second band widest, fused on posterior third with third band, both in turn connected to first band near apex, fourth band shortest, contiguous to anterolateral margin and restricted to first third of elytron, fifth band present on posterolateral margin, starting at about end of fourth band and ending near apex; first four bands connected on anterior region.

Head. Broad, surface without punctation. Antennae 11-segmented; scape shortest; pedicel about three times longer than scape; antennomeres III–VI short; antennomere VII broadest; antennomeres VIII–X, twice as long as antennomeres III–VI, slightly shorter than antennomere VII; antennomere XI longest, twice as long as antennomere VII, acuminate at tip. Maxillary palpus 4-segmented; palpomeres I–III short; palpomere IV notched at apex. Labial palpus 4-segmented; palpomeres I–III very short, subconical; palpomere IV clearly longer than first three combined, broad and flat with small protuberance on inner margin.

Thorax. Pronotum convex, lateral bead narrow; anterior and lateral margins with punctures producing long, thin, golden setae; crease at posterolateral angle clearly demarcated, extending to pronotal half length. Elytra moderately convex; maximum width at about anterior fifth; surface with scattered punctation, with long golden setae at base and on lateral and apical margins. Prosternum ( Fig. 4 ) with anterior margin sinuate, with a distinct line of 4–5 stiff setae on each side of middle, anterior to procoxae and prosternal process; prosternal process relatively broad, with length greater than width, narrow between procoxae, then widening to subrectangular plate with posterior margin truncate, slightly convex; with dense punctation and short golden setae scattered over entire surface. Metaventrite large, posteriorly continuous with noterid platform, anteriorly receiving apex of prosternal process. Noterid platform with lateral margins slightly and evenly divergent, posteriorly divided into two subtriangular lobes (metacoxal processes) separated by deep notch medially; with dense punctation and short golden setae scattered over entire surface; metacoxal lobes each with thick setal comb on posterolateral angle.

Legs. Protibia with comb of setae on outer margin, apex with robust, curved spur. Protarsus attached along side of protibia, with protarsomere I largest, longer than protarsomeres II–IV combined, protarsomere V long, slender. Metafemur broad with thick comb of long setae on distal inner angle. Metatibia with series of long natatory setae and two spurs on distal inner angle, anterior spur not serrate, posterior spur longest, serrate. Claws subequal in length.

Abdomen. Triangular; composed of six smooth ventrites; ventrites I–III fused; ventrite I divided by metacoxae, suture separating it from ventrite II visible; ventrites IV and V each with transverse row of setae; ventrite VI subtriangular.

Male genitalia ( Figs 7–11 ). Aedeagus asymmetrical; right lateral wall of segment IX ring-like ( Figs 7 , 11a ), anteroventral margin projecting forward, posterior margin bilobed, ventral lobe more projecting backwards, left lateral wall of segment IX apically with 5–6 robust spine-like setae in two groups and several hair-like setae; left lateral lobe in lateral view ( Figs 8 , 11b ) elongate, very slender, slightly curved, with hair-like setae on distal third, longer at apex forming a tuft; right lateral lobe in lateral view ( Figs 9 , 11c ) short, subtriangular, laminar, narrow at base, broadening towards apex, with deep longitudinal groove on dorsal side, creating an inward fold; median lobe ( Figs 10 , 11 d–f) robust, longer than lateral lobes, in lateral view broadest at about basal third, then narrowing up to distal two thirds, distal third about parallel sided, apex rounded; curved dorsally, ventrally with deep longitudinal groove subtended by lateral flanges, left lateral flange slightly enlarged, expanded ventrally, converging with right side at or near apex to create a flattened lobe; base comprised of small lateral notches and a medial hook-like process.

Measurements. Holotype [paratypes, mean]: TL = 2.5 mm [2.45–2.55 mm, mean = 2.5 mm]; GW = 1.35 mm [1.35–1.45 mm, mean = 1.4 mm]; TL/GW = 1.82 [1.68–1.85, mean = 1.80]; TLVP = 1.10 mm [1.1–1.2 mm, mean = 1.15 mm]; HW= 0.8 mm [0.75–0.8 mm, mean = 0.75 mm]; EW = 0.4 mm [0.4–0.45 mm, mean = 0.4 mm].

Female. Unknown.

Differential diagnosis. Suphisellus grossoi sp. n. is distinguished from other species of the genus by the following combination of characters: (1) small size (total length 2.4–2.6 mm), (2) elytra with longitudinal bands, with weak punctation, (3) lateral margins of prosternal process almost straight, and (4) male genitalia. The new species belongs to a group of species with vittate elytra, however it can be readily distinguished from the other species of this group by its smaller size (TL = 2.4–2.5 mm) (TL> 2.7 mm in the other species). Suphisellus simoni (TL = 2.7–3.1 mm), S. canthydroides (TL = 2.8 mm) and S. lineatus (TL = 2.8–3.0 mm) are closer in size to S. grossoi sp. n., but S. simoni can be distinguished by the different shape of the male median lobe, which is slender and sharp at tip ( Scheers & Thomaes 2017). Suphisellus canthydroides can be distinguished from the new species by the presence of a strong and dense punctation on the elytra, and by the male left lateral lobe bearing two strands of hairs ( Grosso 1979). In S. lineatus , the pattern of elytral longitudinal bands is well defined whereas in S. grossoi sp. n. it is more diffuse; in addition, segment IX is characterized by the presence of 10 robust spine-like setae in S. lineatus (see Grosso 1979) (5–6 robust spine-like setae in the new species).

Remarks. Four specimens from São Paulo, housed in the ZSM (photographs kindly provided by Mario Toledo) and determined by Zimmermann to be members of S. flavolineatus , are most likely conspecifics of S. grossoi sp. n. In spite of this we decided not to include them within the type series because we didn’t have enough information of them.

Co-occurring taxa. Adults of S. grossoi sp. n. were collected with a light trap together with other noterid species: Hydrocanthus paraguayensis Zimmermann, 1928 , Suphis cimicoides Aubé, 1837 , Suphis insculpturatus Zimmermann, 1921 , Suphis minutus Régimbart, 1903 and Suphisellus nigrinus (Aubé, 1838) .

Distribution. Brazil, Paraguay.

Etymology. This species is dedicated to Luis E. Grosso in recognition to his contributions to the noterid fauna of Argentina. Also, the new species described in this paper was first included in Grosso’s doctoral thesis ( Grosso 1979) under the name Suphisellus vidalae , although it was never availably published. The name is a noun in the genitive case.

Figures

FIGURES 1–3. Suphisellus grossoi sp. n. (male paratype): (1) Habitus, dorsal aspect; (2) Habitus, ventral aspect; (3) Habitus, lateral aspect. Scale bar = 1 mm.

FIGURES 4–6. Prosternum of male of Suphisellus species, ventral aspect: (4) S. grossoi sp. n.; (5) S. grammicus; (6) S. flavolineatus. Scale bar = 0.5 mm.

FIGURES 7–10. Male genitalia of Suphisellus grossoi sp. n.: (7) Apex of segment IX, right lateral aspect; (8) Left lateral lobe, right lateral aspect; (9) Right lateral lobe, right lateral aspect; (10) Median lobe, right lateral aspect. Scale bars = 0.05 mm for Fig. 7 and 0.25 mm for Figs 8–10.

FIGURES 11–13. Male genitalia of Suphisellus species: (11) S. grossoi sp. n.; (12) S. grammicus; (13) S. flavolineatus: a) segment IX, right lateral aspect; b) left lateral lobe, right lateral aspect; c) right lateral lobe, right lateral aspect; d) median lobe, left lateral aspect; e) median lobe, dorsal aspect; f) median lobe, right lateral aspect. Scale bar = 0.5 mm.