Exocelina kobau Shaverdo & Balke

Shaverdo, Helena, Surbakti, Suriani, Warikar, Evie L., Sagata, Katayo & Balke, Michael, 2019, Nine new species groups, 15 new species, and one new subspecies of New Guinea diving beetles of the genus Exocelina Broun, 1886 (Coleoptera, Dytiscidae, Copelatinae), ZooKeys 878, pp. 73-143 : 73

20. Exocelina kobau Shaverdo & Balke sp. nov. Figs 46 , 50

Type locality.

Papua New Guinea: Morobe Province, E Pindiu, Kobau, ca. 6°25'10.1"S, 147°32'06.6"E, 1400 m a.s.l.

Type material.

Holotype: male "PAPUA N.G.: Morobe Prov. E Pindiu, Kobau 24.4.1998, 1400 m, leg. A. Riedel", "SEM 13" (NHMW).

Description.

Body size and form: Beetle medium-sized: TL-H 4.25 mm, TL 4.75 mm, MW 2.2 mm, with oblong-oval habitus.

Colouration: Piceous, with paler sides of pronotum and head anteriorly. Head dark brown, paler anteriorly. Pronotum dark brown, with brown sides. Elytra piceous, with weakly indicated reddish sutural lines. Head appendages and legs proximally reddish, legs distally darker, reddish brown ( Fig. 46 ).

Surface sculpture: Shiny dorsally, with extremely fine and sparse punctation and weakly impressed microreticulation. Head with fine and sparse punctation (spaces between punctures 2-3 times size of punctures); diameter of punctures equal to or smaller than diameter of cells of microreticulation. Pronotum with much finer and sparser punctation than on head, very inconspicuous. Punctation on elytra invisible. Pronotum and elytra with weakly impressed microreticulation; head with microreticulation slightly stronger. Metaventrite, metacoxae, and abdominal ventrites distinctly microreticulate. Metacoxal plates with longitudinal strioles and weak transverse wrinkles; abdominal ventrites with strioles. Punctation on venter invisible; inconspicuous on two last abdominal ventrites.

Structures: Pronotum with lateral bead. Base of prosternum and neck of prosternal process with distinct ridge, slightly rounded anteriorly. Blade of prosternal process lanceolate, relatively narrow, slightly convex, with distinct bead and few setae laterally. Abdominal ventrite 6 truncate.

Male: Protarsomere 4 with large, thick, strongly curved anterolateral hook-like seta. Protarsomere 5 ventrally with anterior band of 25 and posterior row of five relatively long setae ( Fig. 50D ). Abdominal ventrite 6 with 3-4 lateral striae on each side. Median lobe short, robust, evenly tapering to broadly pointed apex in lateral and ventral views ( Fig. 50A, B ). Paramere slightly concave on dorsal side, subdistal setae strong and dense, proximal setae inconspicuous ( Fig. 50C ).

Female: Unknown.

Affinities.

Exocellina kobau sp. nov. can be distinguished by its size, dorsal punctation, shape and setation of its median lobe and paramere, and large anterolateral hook-like seta of the male protarsomere 4 from the species co-occurring in the same area ( E. damantiensis , E. kabwumensis Shaverdo & Balke, 2016, and E. bacchusi ). For the affinities within the group, see the “Key”.

Distribution.

Papua New Guinea: Morobe Province ( Fig. 54 ).

Etymology.

The species is named after Kobau Village. The name is a noun in the nominative singular standing in apposition.

Figures

Figure 54. Map of the eastern part of New Guinea showing distribution of the species of the E. warasera group.

Figures 46 - 49. Habitus and colouration 46 Exocelina kobau sp. nov. 47 E. pulchella sp. nov. 48 E. warasera sp. nov. 49 E. haia sp. nov.

Figures 50, 51. 50 Exocelina kobau sp. nov. 51 E. pulchella sp. nov. A median lobe in ventral view B median lobe in lateral view C paramere in external view D male protarsomeres 4 - 5 in ventral view.