Platambus brancuccii, Hendrich, Lars & Przewoźny, Marek, 2015

Hendrich, Lars & Przewoźny, Marek, 2015, Two new species of the genus Platambus Thomson, 1859 from China (Coleoptera: Dytiscidae, Agabinae), Zootaxa 3947 (2), pp. 191-200 : 192-193

Platambus brancuccii sp. n.

( Figs 5, 6, 7 , 9 , 16 )

Type locality. China, Ganzi Tibetan Autonomous Prefecture, Sichuan Province, 60 km W of Litang, ca. 30°15'N 99°44'E.

Type material. Holotype, male: “ China Sichuan Litang 60 km W of Xianscheng [ca. 30°15'N, 99°44'E], 1600 m, 12.-18.VI.2010, Z. Linek leg.”, “ Holotype Platambus brancuccii sp.n. Hendrich & Przewoźny des. 2014” [red printed label] ( ZSM). Paratypes. 2 males and 14 females with same data as holotype and provided with red printed paratype label ( CGW, CLH, CMP, NMPC).

Remarks. According to Prof. Lanzhou Ji “Litang” is a county name and belongs to Ganzi Tibetan Autonomous Prefecture, Sichuan Province, ca. 300 km west of Kangding. In Chinese “ 60 km W of Xianscheng” means “ 60 km W of Litang”. The area 60 km west of Litang is higher than 4000 m, so the given altitude on the locality label is incorrect.

Diagnosis. Medium sized Platambus with elongate, oval and slightly flattened body. Dorsal surface almost black with pale pattern as depicted in Figs 5–7 .

Description. Measurements: Holotype: Total body length 8.6 mm, body length without head 7.6 mm, width 4.3 mm. Paratypes: Total body length 8.2–8.8 mm, body length without head 7.4–7.6 mm, width 4.2–4.3 mm.

Head brownish, paler alongside anterior and basal margins, appendages reddish. Reticulation consisting of well impressed polygonal meshes, irregular in size, with several very small punctures within them, and larger punctures at intersections of meshes. Large punctures compose row alongside eyes, and distinct fronto-clypeal fovea.

Pronotum cordiform, broadest in middle. Lateral margin rounded in anterior half, sinuated before posteriors angles. Posterior angles acute. Pronoto-elytral angle distinct. Coloration dark brown to black with anterior angles somewhat yellowish. Reticulation similar to that on head. Anterior margin with row of large setigerous punctures, similar row near posterior margin, broadly interrupted at middle. Lateral margin broadly and distinctly bordered.

Elytron black with broad yellowish lateral band along two third of elytron ( Figs 5, 6, 7 ). Epipleura ferruginous. Reticulation consisting of weakly, but distinctly impressed polygonal meshes, with several minute punctures within them, and larger punctures at intersections of almost all polygonal meshes. Each elytron with sutural, discal and lateral rows of large serial setigerous punctures.

Ventral side completely ferrugineous. Reticulation consisting of small polygonal meshes. Prosternal process elongate, lanceolate, bordered laterally and produced into long sharp point. Mesofemora and mesotibia ventrally with numerous large setigerous punctures. Metasternal wings narrow. Metacoxa with large punctures and irregular groves laterally. Metatrochanter rounded at apex. Metafemora without setae or large punctures near posterolateral angle. Metatibia ventrally with two longitudinal rows of large punctures. Ventrites with oblique groves, anal ventrite posteriorly with transverse corrugations and dense smaller punctures.

Male. Tarsomeres 1–3 of fore and middle legs weakly dilated with small bristles on ventral side. Median lobe in lateral view broad, only slightly narrowing toward tip, slightly curved in apical third, tip broadly rounded ( Fig. 9 a), in ventral view as in Fig. 9 b.

Female. Habitually similar to male. Tarsomeres of fore and middle tarsi not dilated.

Etymology. Named after of our highly valued colleague, the late dytiscid specialist Michel Brancucci (1950– 2012), Basel, Switzerland. The specific epithet is a substantive in the genitive case.

Affinities. Platambus brancuccii sp. n. is habitually very similar to P. korgei sp. n. and P. wewalkai Brancucci, 1982 but can be recognized from P. korgei sp. n. by the more cordiform pronotum with posterior angles prominent, and the pale lateral band on two thirds of elytron; from P. wewalkai by a more oblong body and larger punctures at almost each intersection of elytral meshes. From both it can be separated by the different shape of male median lobe.

Habitat. Nothing is known about the life habitat of the species. Probably a lotic species living in small mountain streams.

Distribution. Only known from the type locality in Sichuan province, China ( Fig. 16 ).

Figures

FIGURE 16. Distribution of the Platambus semenowi- group in Central Asia, the Himalaya region and China.

FIGURES 5 – 8. Habitus of Platambus brancuccii sp. n., male (holotype) (5), male (paratype) (6), female (paratype) (7), P. korgei sp. n., male (paratype) (8). Scale bar 4 mm. Photos: Marek Przewoźny.

FIGURES 9 – 10. Aedeagus in lateral (a) and ventral view (b) of: Platambus brancuccii sp. n. (9 a / b) and P. korgei sp. n. (10 a / b). Scale bar 0.5 mm.