Gyrinus rhyssonotum sp. n., a new species of Gyrinidae (Coleoptera: Adephaga) from northern Brazil Author Colpani, Daniara Author Benetti, Cesar João Author Hamada, Neusa text Zootaxa 2019 2019-02-22 4560 1 164 170 journal article 27426 10.11646/zootaxa.4560.1.9 46a9a555-d7e0-4e1b-b9af-0ffa615c50d4 1175-5326 2627504 7E75C43C-4781-46C3-93CD-EDA0B5142434 Gyrinus ( Oreogyrinus ) rhyssonotum sp. n. ( Figs 1 A–E, 2A–B, 3A–C) Type locality. BRAZIL , Amazonas state, Barcelos County , Serra do Aracá , 00°54'03.89"N 63°25'45.30"W ( Figs 3 A–C) . Type material. Holotype ♂ (INPA, pinned) “ BRAZIL , Amazonas State , Barcelos County , Serra do Aracá , first-order stream, 00°54'03.89"N 63°25'45.30"W , 1104 m , 27.VII.2009 , leg. Pes, A.M.O. &. Hamada, N.”. Paratypes (29 exs): 2 ♂ , 8 ♀ ( 1 ♂ , 7 ♀ INPA , pinned; 1 ♂ , 1 ♀ ZSM , pinned), same locality as holotype; 2 ♂ ( INPA , pinned), same locality except “pond near Igarapé da Anta , 30.VII.09 , leg. Pes, A.M.O. &. Hamada, N.”; 10 ♂ , 7 ♀ ( INPA , alcohol) same data except “stream, Igarapé da Anta , 00°54'30.38"N 63°26'24.32"W , 116 m , 01.VIII.09 , leg. Pes, A.M.O. &. Hamada, N.” . Diagnosis. Pronotal and elytral margins broad ( Fig. 1A ); elytral disc lacking reticulation, appearing polished; elytral striae VII–IX sulcate, striae I–XI with mostly distinct round punctures in longitudinal series; elytral apex round to slightly truncate ( Fig. 1A ); epipleural angle indistinct; median lobe of aedeagus shorter than parameres, broad, with apex broadened and almost truncate, base 1.4 times broader than apex ( Fig. 2A ); parameres broad with apex truncate, with slightly prominent internal angle; gonocoxae elongate, with apices truncate ( Fig. 2B ). Description. Male. Habitus . Medium-sized species. Body oval, broad, weakly convex in lateral view, greatest convexity near elytral mid-length, evenly depressed anteriorly and posteriorly ( Fig. 1A ). Measurements (n = 20). TL: 4.44–4.95 mm ; MW: 2.53–2.80 mm ; HL: 0.74–0.95 mm ; HW: 1.52–1.73 mm ; CL: 0.12–0.17 mm ; CW: 0.66–0.76 mm ; DD: 0.50–0.59 mm ; LW: 0.45–0.63 mm ; PL: 0.75–0.81 mm ; EL: 3.23– 3.72 mm ; EH: 1.25–1.67 mm ; EW: 1.23–2.80 mm ; PTL: 0.80–0.96 mm ; PFL: 1.07–1.21 mm ; PFW: 0.29–0.33 mm ; PTAL: 0.45–0.50 mm ; PTAW: 0.15–0.19 mm . FIGURE 1. Distribution and habitat of Gyrinus rhyssonotum sp. n. : A) type locality (blue circle) and other record (green square), in Serra do Aracá, Amazonas state, Brazil. B–C) overview of the first-order stream (type locality) where the new species was collected. Coloration ( Figs. 1 A–C). Head, pronotum and elytra black, with blue metallic reflections ( Fig. 1A, B ); lateral margins of pronotum and elytra (striae VIII–XI) with reflections bronzy yellow and green. Ventral view dark brown, with bronzy metallic reflections; labial palpomeres and last maxillary palpomere with dark-brown apices; meso and metacoxae darker with orangish-yellow pitches apically; abdominal ventrites VII and VIII reddish brown to dark orange yellow; legs dark yellow to orangish-yellow with dark spots. Sculpture and structure (at a magnification of 120×). Head. 2.0 times wider than long ( Fig. 1B ); front with two round depressions; frontolateral margins convex, reticulation evident, composed of scale-like sculpticells; vertex and frons with striae evident and sparse punctures separated by 2– 4X diameter of a puncture, frontolateral and postocular margins wrinkled ( Fig. 1B ); clypeus 1.2 times longer than labrum, with anterior edge nearly straight, frontoclypeal suture with posterior margin sinuous, lateral margins slightly convex ( Fig. 1B ), reticulation evident, composed of scale-like sculpticells, striae evident throughout the clypeus, punctures sparse, separated by 2– 4X diameter of a puncture; labrum convex, punctation strongly impressed on anterior margin, separated by 1.5–2.0X diameter of a puncture. Thorax . Pronotum. Anterior margin sinuous, posterior margin slightly curved, lateral margins broad and wrinkled ( Figs 1A,B ); pronotal transverse line strongly impressed with well marked wrinkles anteriorly and posteriorly ( Fig. 1 B–D); pronotal disc with well impressed wrinkles and dense micropunctures ( Figs 1C, D ); punctures present throughout the pronotum, strongly impressed, separated by 1.5–2.0X their diameter ( Fig. 1D ). Elytra. Striae VII–IX sulcate, intervals I–III with linear disposition basally, intervals I–VI convex; stria XI strictly marginal; elytral margin uniform over almost all of its length, narrowing near epipleural apical angle ( Fig. 1A ); lateral margin separated from apex by a plica; fine punctation present among elytral intervals I–XI, distance between the nearest punctures 1.5–2.0X diameter of a puncture ( Fig. 1E ); large punctures of elytral series well marked ( Fig. 1E ); elytral apex rounded to slightly truncate; epipleural angle slightly distinct, sutural angle distinct ( Fig. 1A ). Mesoventrite grooved on lateral margin, apex with anterior margin rounded, groove evident in medial portion, extending to the posterior portion; medial pit present; setae present on anterolateral region. Profemur 3.7X longer than maximum width. Protarsus dorsally convex, broad, 2.6–3.0X longer than wide, about 1/ 3X length of protibia. Abdomen . Tergite VIII wider than long, apex rounded, with light yellow setae present on the entire surface, with weak longitudinal carina, ending before reaching apex. FIGURE 2. Gyrinus rhyssonotum sp. n. : A) male adult, dorsal view, scale bar = 1 mm. B) head and pronotum, scale bar = 0.5 mm. C) pronotum, wrinkles. D) pronotum, punctures in the median region. E) elytra, fine punctation between rows of larger punctures. Aedeagus ( Fig. 2A ). median lobe of aedeagus shorter than parameres, broad, in dorsal view with lateral margins sinuous, weakly attenuated at the end of basal 2/3 and then broadened in apical 1/3 towards apex, which is slightly triangular and weakly raised medially; width of median lobe about 0.8 times width of apex of parameres; base 1.4 times broader than apex; in lateral view median lobe thick, dorsally curved. Parameres broad, with apex strongly truncate and slightly prominent internal angle. Female . Sculpture (micropunctures and wrinkles) more evident than in male. Elytral disc free of reticulation, elytral intervals I–XI with fine punctation. Gonocoxae ( Fig. 2B ) elongate, straight, narrowed at middle, with external and internal margins slightly concave, apex truncate, slightly concave; base wider than apex. Etymology. The specific epithet rhyssonotum refers to the quite evident wrinkles on the pronotum; rhysso (G.) = wrinkled; notum (G.) = the back). Distribution. This species is currently known only from the Barcelos county, Amazonas State, in northern Brazil ( Fig. 3 A–C). Habitat. Specimens of this species were collected in streams and pools ( Fig. 3 B–C).