Platynectes (Platynectes) meru, Gustafson & Short & Miller, 2016

Gustafson, Grey T., Short, Andrew E. Z. & Miller, Kelly B., 2016, New species of diving beetles in the subgenus Platynectes s. str. from the Guiana Shield (Coleoptera: Dytiscidae: Agabinae), Acta Entomologica Musei Nationalis Pragae 56 (1), pp. 79-102 : 90-92

Platynectes (Platynectes) meru sp. nov.

( Figs 1 , 9 , 15 )

Type material. HOLOTYPE: J, “ VENEZUELA: Amazonas State / 5°23.207′N, 67°36.922′W, 125 m / Tobogan de la Selva; 14.i.2009 / Detrital rock pools / leg. K. Miller; VZ09-0114-01E [white label, typed black ink]”, “SM0846231 / KUNHM-ENT [white label, type black ink with bar code]” ( MIZA) . PARATYPES (13 spec.): same as holotype except: SM0846222, SM0846237, SM0846238, SM0846249, SM0846261, SM0846263, SM0846265, SM0846268 (9 spec. SEMC) ; same data as holotype except: leg. Short & Miller, partly shaded wet rock w/ algae, VZ09-0114- 01G, SEMC0879600 (1 spec. SEMC) ; “ Venezuela: Amazonas, Tobogan de la Selva , 125 m, 14.i.2009, 5°23.207′N 67°36.922′W, K. Miller (VZ09-0114-01E)”,“MB 6292”,“MB 6293” (2 spec. ZSMG) ; “ Venezuela: Estado Amazonas, Tobogan de la Selva , 24.-25.i.2004, M. Balke & M. Garcia ”, “DNA M Balke 0648” (1 spec. ZSMG) .

Diagnosis. Small sized (4.8–5.0 mm in length), elongate oval in dorsal habitus, elytron with five well-demarcated yellow spots.

Description. Size. Male: TL = 4.8–5.0 mm, TL-h = 4.3–4.4 mm, TW = 2.9–3.0 mm; female: TL = 4.8–4.9 mm, TL-h = 4.2–4.4 mm, TW = 2.8–2.9 mm.

Body elongate oval, lateral margins evenly curved and continuous between pronotum and elytron ( Fig. 1 ).

Coloration ( Fig. 1 ). Head orange grading into diffuse, light yellow region medially on frons and testaceous to black mediad and posteriad of eyes, in some specimens extending anteriorly around eye to lateral margin of frons. Pronotum broadly black or testaceous medially along anterior and posterior margins, black regions meeting medially in lighter, testaceous transverse band; posterolateral margins of pronotum narrowly black, lateral surfaces yellow, extending medially to dark region; scutellum testaceous. Elytron testaceous, with five yellow spots, one round parascutellar, one round humeral, one transverse slightly anterior of middle near suture, one transverse slightly posterior of middle near lateral margin, and one transverse anteapically. Appendages of head, legs and ventral surfaces, including elytral epipleuron, pale orange to reddish, somewhat darker on thoracic sterna and metacoxae; last abdominal tergite yellow.

Structure and sculpture. Head broad and short, anterior clypeal margin broadly rounded; entire dorsal surface of head with small highly irregular cells, each cell with fine punctures, additional irregular covering of fine punctation throughout. Pronotum broad and short, medially with small shallow dimple; lateral bead distinct and broad, evenly curved, about width of antennomere V; surface shiny, covered with fine microreticulation of irregular cells, cells with fine punctures, additional punctation consisting of a row of large coarse punctures on anterior and posterior margin, punctures separated by ca. 0.5–1× diameter of a puncture anteriorly, posterior row mostly effaced by reticulation medially, laterally punctures separated by ca. 1–2× diameter of a puncture. Elytron with lateral margins evenly curved to slightly angulate apex, lateral epipleural carina distinctly visible throughout length; surface covered with weakly impressed, but distinct microreticulation of large irregular cells, cells also with fine punctures; elytral epipleuron slender, evenly tapered to apex. Prosternum medially moderately long, longitudinally swollen; prosternal process broad, lateral margins broadly curved to somewhat pointed apex, surface flat to slightly curved, smooth. Metaventrite with anterior process broad, with broadly curved emargination for reception of prosternal process; lateral wings broad, WC/WS = 5; surface smooth, microreticulation very weakly impressed, composed of short, irregular cells laterally, and more elongate cells medially, dense weakly impressed punctation medially, punctures separated by ca. 2–3× diameter of a puncture. Fore- and midlegs slender, surfaces punctate, protibial apices with largest spine longer than protarsomeres I+II, reaching 1/2 length of protarsomere III; mesotibal apices with longest spine just shorter than length of mesotarsomeres I+II, mesotarsal spurs elongate slender, as long as mesotarsomere I+II; metacoxae smooth, microreticulation weakly impressed, composed of short, round cells laterally, and more elongate rectangular cells medially, punctation fine and weakly impressed, punctures separated by 2–3× diameter of a puncture, metacoxal lines distinct, broadly divergent anteriorly; hind legs slender, smooth, metafemur with fine weakly impressed reticulation composed of elongate cells, almost imperceptible weakly impressed punctation, setigerous punctures on anterior surface of metatibia and metatarsomere I, metatrochanter apically spinous, metatibial spurs slender, anterior 2/3 length as metatarsus I, posterior spur as long as metatarsus I. Abdominal ventrites broad, smooth and unmodified, with fine weakly impressed reticulation, composed of irregular elongate cells, punctation nearly imperceptible.

Male genitalia ( Fig. 9 ). Median lobe broad, in left lateral view strongly curved, apex strongly expanded and narrowly rounded, apical 2/3 small covered in pores; ventral groove in right lateral view consistent in width, no narrowing apically, apical opening relatively broad. Sexual dimorphism. There appears to be no sexual dimorphism evident from the specimens studied.

Variation. Very little variation was observed, all specimens similarly sized.

Differential diagnosis. Platynectes meru sp. nov. is most similar to P. submaculatus in elytral maculation pattern, having five yellow well-demarcated spots, but differs in being smaller (body length = 4.8–5.0 mm), and more regularly oval in dorsal habitus ( Fig. 1 ). The aedeagus ( Fig. 9 ) will unambiguously separate the two species as the median lobe of P. meru sp. nov. is strongly curved whereas that of P. submaculatus is relatively straight.

Etymology. This species is named after the Pemon word for waterfall, “ meru ”. This is also in reference to the fact that this is the type locality for the family Meruidae . Noun in apposition. Natural history. The larger series for this species was taken in a densely forested detrital pool that was adjacent to a forested creek. These pools were formed by depression in the granite bedrock that is exposed around the site. One specimen was collected in a small detritus and algal covered seepage flowing into the creek.

Distribution. Only known from the type locality at Tobogan de la Selva in southwestern Venezuela ( Fig. 15 ).

Figures

Figs 1–6. Dorsal habitus of Platynectes species. 1 – P. meru sp. nov. 2 – P. decemnotatus (Aubé, 1838). 3 – P. elaskanaima sp. nov. 4 – P. tafelbergensis sp. nov. 5 – P. submaculatus (Laporte, 1835). 6 – P. garciai sp. nov. Scale bar = 2 mm.

Figs 7–13. Median lobe of aedeagus of Platynectes species, top row left lateral view, bottom row right lateral view. 7 – P. submaculatus (Laporte, 1835). 8 – P. elaskanaima sp. nov. 9 – P. meru sp. nov. 10 – P. decemnotatus (Aubé, 1838). 11 – P. garciai sp. nov. 12 – P. tafelbergensis sp. nov. 13 – P. agallithoplotes sp. nov.

Fig. 15. Distribution map of Platynectes species of northern South America.