Taxonavigation

Familia: Dytiscidae
Subfamilia: Agabinae
Genus: Platynectes
Species: Platynectes brancuccii

Name

Platynectes brancuccii Hendrich & Šťastný, 2014

Type locality

Tributary of Nigger Creek, 17.483S 145.467E, 1100 m, 23 km S Atherton, northern Queensland, Australia.

Type material

Holotype: 1 male: “Australia Qld. Nigger Cr. Trib. 23 km S Atherton Oct. 18/90 Larson”, “Platynectes lemniscata Larson n.sp. MS name”, “Holotype Platynectes brancuccii sp. n. Hendrich & Šťastný 2014 des.” [red printed label] (ANIC). - Paratypes: males and 1 female with same data as holotype (ANIC, CJS, CLH); 2 males: “Australia Qld, Trib. Kauri Cr. L. Tinaroo Oct. 29.1990 Larson”, “Platynectes lemniscata Larson n.sp. MS name” (ANIC, CLH); 1 male and 1 female: “Australia Qld, Kauri Cr. Tinaroo L., NE Atherton Oct. 24/90 Larson”, “Platynectes lemniscata Larson n.sp. MS name”, “SAMA Database No 25-006387 S Aust. Museum specimen” (SAMA). All paratypes provided with a red printed paratype label.

Diagnosis

Body small, oval, rather flat, usually shiny, black with seven distinct longitudinal lines of yellowish spots on elytron (Fig. 1).

Description

Measurements: Holotype: TL = 5.6 mm, TL-H = 5.0 mm; width = 3.4 mm. Paratype: TL = 5.6–5.8 mm, TL-H = 5.0–5.2 mm; width = 3.4–3.45 mm.

Head: black, dull, with one central large yellow spot not reaching posterior margin. Microreticulation absent. Reticulation strong, consisting of small meshes and larger punctures at interspaces of meshes and of minute punctures inside meshes. Two small and shallow clypeal grooves on disc and a shallow transverse depression formed by deep and coarse punctures beside eyes. Antennae testaceous, long; antennomeres slender. Apical two antennomeres reaching elytron.

Pronotum: completely black, shiny with anterior angles yellow. Posterior angles of pronotum acute. Reticulation strong, consisting of small meshes and larger punctures at interspaces of meshes and of minute punctures inside meshes. Longitudinal median suture visible but very short. Anterior and posterior rows of punctures coarse; punctures moderate to small and well separated. Lateral margin, except in anterior fifth, completely bordered.

Elytron: black, shiny with seven longitudinal lines of yellow spots on each elytron. Epipleura testaceous. Reticulation fine but present at usual magnification (80×), consisting of small meshes and larger punctures at interspaces of meshes and of minute punctures inside meshes. Sutural row of punctures not visible. Discal row of small punctures interrupted just before anterior edge.

Ventral surface: rufo-piceus. Legs rufo-testaceous. Prosternal process broad, 1.5 times as long as broad, distinctly bordered at sides, and sharply pointed out at apex. Metaventral wings very narrow. Metacoxal lines raised, well separated, a little divergent in anterior half. Metacoxal plate with few narrow scratches, microreticulation consisting of minute punctures. Abdominal ventrites 1, 2 and 3 laterally with a yellow spot. Last ventrite narrowly microreticulate with minute punctures and with some strong oblique striations reduced to a series of punctures in some females. Posterior margin bordered and broadly rounded.

Male: Protarsus little expanded, moderately clothed with setae ventrally. Aedeagus: Median lobe regularly curved in lateral view, apical part markedly bent and rounded. In ventral view, apical part asymmetrical and expanded to right hand side (Fig. 2 - 9a, 9b). Parameres narrow, elongate with long setae and in apical third markedly bent (Fig. 2 - 10).

Sexual dimorphism: Females differ from males in the following characters: Meshes of dorsal surface reticulation more deeply engraved, surface appearing less shiny, striation on last abdominal ventrite reduced to a series of punctures, and pro- and mesotarsomeres 1–3 not dilated and without adhesive setae.

Variability: Variability. Specimens examined show slight variation in the extent of yellow color pattern on head and size of body.

Affinities

Within the Australian members of the decempunctatus-group P. brancuccii sp. n. is characterized by longitudinal lines of yellow spots on each elytron, small size and roundish and flattened body. From other maculate forms of P. decempunctatus like P. polygrammus Régimbart, 1899 or P. ocularis Lea, 1895, both described from Western Australia, P. brancuccii sp. n. can be distinguished by its much smaller size (7.5–8.0 mm in P. polygrammus and P. ocularis) and the shape of the median lobe having the apical part asymmetrical and expanded to the right hand side in ventral view.

Habitat

Lotic. According to the label data collected in different creeks and streams.

Etymology

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

Distribution

(Fig. 3). Only known from the type locality at Atherton Tableland in north-eastern Queensland.

Images

• 
  Figure 1. Platynectes brancuccii. (Photo: Michael Balke)
• 
  Figure 2. Median lobe and parameres of Platynectes brancuccii. (Drawing: Jaroslav Šťastný)
• 
  Figure 3. Distribution map of Platynectes brancuccii, north-eastern Queensland, Australia

References

• Hendrich, L.; Šťastný, J. 2014: Taxonomic revision of Australian Platynectes Régimbart, 1879 (part I)—four new species from Queensland (Coleoptera: Dytiscidae, Agabinae). Zootaxa 3795(1): 25–37. DOI: 10.11646/zootaxa.3795.1.3 Reference page.