Platynectes (Platynectes) colombicus, Short & Benetti & Gustafson, 2020

Short, Andrew Edward Z., Benetti, Cesar J. & Gustafson, Grey T., 2020, New records of Platynectes (s. str.) diving beetles from South America with description of two new species (Coleoptera: Dytiscidae: Agabinae), Acta Entomologica Musei Nationalis Pragae 60 (2), pp. 437-447 : 440-442

Platynectes (Platynectes) colombicus sp. nov.

( Figs 3 , 8–9 , 14 )

Type material: HƟĿƟτΥΡ*ú:♁ (IvH), labelled: ‘ COLOMBIA: Meta / ca. 1.3km NE Jardin de las Peñas / 26.II.2015, leg. M.A. Jäch (CO9)’, ‘small stream / 740 m / 3°17’21.04”N 74°9’20.74”W’.

Description. Body evenly oval, lateral margins evenly curved and continuous between pronotum and elytron.

Coloration ( Fig. 2 ). Head orange grading into diffuse, light yellow region medially on frons and testaceous to black mediad and posteriad of eyes. Pronotum medially testaceous with two transverse darkly colored bands along anterior and posterior margins, posterolateral margins narrowly black, lateral surfaces yellow extending medially to dark region; scutellum testaceous. Elytron testaceous medially, more lightly colored laterally, with five yellow spots, one well-demarcated parascutellar spot, one posteriad of humeral region, one weakly-demarcated band-like spot slightly anterior of middle near suture, one slightly posterior of middle near lateral margin, and one large spot anteapically. Appendages of head apically, propleuron, and epipleuron lighter orange in color, thoracic sterna and legs red in color; abdomen entirely orange in color.

Head broad and short, anterior clypeal margin weakly rounded; anterior surface of frons and clypeus with fine, dense punctation, posterior surface of head with fine microreticulation of irregular cells, most cells also with fine punctures.

Pronotum broad and short; lateral bead distinct and relatively narrow, weakly curved, similar in width to anterior epipleural carina; surface shiny, covered with fine microreticulation of large, irregular cells, cells with fine punctures, additional punctation consisting of a row of large course punctures on anterior and posterior margins, punctures separated by ca. 1.0–2.0× diameter of a puncture anteriorly, ca. 1.5–4.0× diameter of a puncture posteriorly, absent medially.

Elytron broad, lateral margins evenly curved to apex, lateral epipleural carina distinctly visible throughout length, narrowing anterior to posteriorly; surface covered with weakly impressed, but distinct microreticulation of large irregular cells, most cells also with fine punctures; elytral epipleuron slender, evenly tapered to apex.

Legs. Fore- and midlegs slender, surfaces punctate, protibial apices with several spines about length of protarsomeres I+II; mesotibal apices with few spines shorter than length of mesotarsomeres I+II, mesotarsal spurs elongate slender, slightly sinuate, as long as mesotarsomeres I+II; metalegs slender, smooth, metafemur with fine reticulation composed of elongate cells, almost imperceptible, weakly impressed punctation, few setigerous punctures on anterior surface of metatibia and metatarsomere I, metatrochanter apically spinous, metatibial spurs slender, longer than metatarsus I.

Ventral part. Prosternum medially moderately long, longitudinally swollen; prosternal process broad, lateral margins broadly curved to broadly round apex, surface flat to slightly curved, smooth. Metaventrite with anterior process broad, with broadly curved emargination for reception of prosternal process; lateral parts of metaventrite (‘wings’) broad, WC/WS = 3; surface smooth, weakly impressed reticulation composed of elongate cells, fairly even covering of fine punctation. Metacoxae smooth, fine reticulation composed of round cells, fine and weakly impressed punctation present, metacoxal lines distinct, broadly divergent anteriorly. Abdominal ventrites broad, smooth and unmodified, with fine reticulation composed of elongate cells, fine weakly impressed punctation present.

Male genitalia ( Figs 8–9 ). Median lobe in left lateral view ( Fig. 8 ) weakly curved, apex rounded, weakly expanded, dorsal surface covered in pores in apical 2/3; ventral groove in right lateral view ( Fig. 9 ) of even width basally to apically, abruptly narrowed in apical 1/8.

Variation. Only a single male specimen was available for study.

Measurements. TL = 7.0 mm, TL-h = 6.5 mm, TW = 4.5 mm.

Differential diagnosis. With venter not infuscate – reddish -orange throughout, the new species is included in the P. submaculatus species group. Platynectes colombicus sp. nov. is most similar to P. decemnotatus being larger in size with a body length greater than 6.6 mm and having 10 distinct yellow elytral maculae. However, it can readily be distinguished from P. decemnotatus by having a much narrower pronotal bead relative to the broad bead of P. decemnotatus . From the single specimen examined, P. colombicus , further differs in having a more evenly rounded dorsal habitus, relative to the broader and more anteriorly attenuated habitus of P. decemnotatus . Finally, the median lobe of the aedeagus will unambiguously distinguish the two species, being weakly curved in P. colombicus with a rounded apex, compared to the more strongly curved median lobe of P. decemnotatus which has a more acutely pointed apex.

Etymology. Named in honor of the country of Colombia, from which the unique type specimen was collected; the name is an adjective.

Distribution. This species is known from a single specimen from the Sierra de Macarena in Central Colombia ( Fig. 14 ).

Figures

Figs 2–5. Dorsal habitus images of Platynectes spp. 2 – P. bicolor sp. nov.; 3 – P. colombicus sp. nov.; 4 – P. ornatifrons Sharp, 1882, syntype; 5 – P. parananus Sharp, 1882, holotype.

Figs 6–9. Median lobes of the adeagus. 6–7 – P. bicolor sp. nov.: 6 – left lateral view; 7 – right lateral view. 8–9 – P. colombicus sp. nov.: 8 – left lateral view; 9 – right lateral view. Scale bars = 0.5 mm.

Figs 12–16. Distribution of Platynectes ‘Clade II’ sensu TƟUඌඌΑιΝτ et al. (2017) in South America. Circles represent previously published localities; stars represent localities newly reported in this paper.