Exocelina skalei Shaverdo & Balke

Shaverdo, Helena, Sagata, Katayo, Panjaitan, Rawati, Menufandu, Herlina & Balke, Michael, 2014, Description of 23 new species of the Exocelinaekari-group from New Guinea, with a key to all representatives of the species group (Coleoptera, Dytiscidae, Copelatinae), ZooKeys 468, pp. 1-83 : 27-28

Taxon classification Animalia Coleoptera Dytiscidae

19. Exocelina skalei Shaverdo & Balke sp. n. Figs 1 A–D, 28

Exocelina undescribed sp. MB4427: Toussaint et al. 2014: Supplementary figs 1-4, Tab. 2.

Type locality.

Indonesia: West Papua Province: Kaimana Regency, Kamaka, 03°48.37'S; 134°14.03'E.

Type material.

Holotype: male "Indonesia w-papua 50km SE Kaimana, Triton bay, vic. Kamaka vill. trail to Kamakawalar lake, S 3°48 ’22” E 134°14 ’02”, 50-100m, 03.II.1994 leg. A. Skale (006a) small pool" (ZSM). Paratypes: 4 males, 3 females with the same label as the holotype, 2 males additionally with green labels "DNA M. Balke 4426", "DNA M. Balke 4427" (CASk, MZB, NHMW, ZSM).

Diagnosis.

Beetle small, broadly oval, piceous, with paler head and pronotum or only with pale anterior part of head and pronotal sides, submatt; pronotum with lateral bead; male antennomeres simple; male protarsomere 4 with medium-sized, slender, slightly curved anterolateral hook-like seta; median lobe with apical discontinuity and deeply concave, bilobed apex in ventral view; paramere without notch on dorsal side, with triangular basal part and thin subdistal part, setae inconspicuous, sparse, thin, and relatively short. This species is similar only to Exocelina vladimiri and probably related to it. In the group, only these two species have outline of the median lobe with apical, not submedial, discontinuity in ventral view and broadly oval habitus. Exocelina vladimiri can be distinguished from Exocelina skalei sp. n. with larger size, absence of the pronotal bead, less concave apex of the median lobe, and paramere setation.

Description.

Size and shape: Beetle small (TL-H 2.9-3.25 mm, TL 3.0-3.6 mm, MW 1.7-1.9 mm), with broadly oval habitus, broadest at elytral middle. Coloration: Head dark brown, sometimes to piceous between eyes and paler anteriorly; pronotum dark brown, sometimes to piceous on disc, with red to reddish brown sides; elytra uniformly dark brown to piceous; head appendages yellowish, legs darker, reddish to reddish-brown, especially metathoracic legs (Fig. 28).

Surface sculpture: Head with dense, coarse punctation (spaces between punctures 1-2 times size of punctures); diameter of some punctures equal diameter of cells of microreticulation. Pronotum and elytra with punctation finer and more evenly distributed than on head but very evident. Pronotum and elytra with evident microreticulation, dorsal surface submatt. Head with microreticulation stronger. Metaventrite and metacoxa distinctly microreticulate, metacoxal figs with longitudinal strioles and transverse wrinkles. Abdominal ventrites with distinct microreticulation, strioles, and fine sparse punctation, coarser and denser on two last abdominal ventrites.

Structures: Pronotum with distinct lateral bead. Base of prosternum and neck of prosternal process with distinct ridge, smooth and rounded anteriorly, without small anterolateral extensions. Blade of prosternal process lanceolate, broad, slightly convex, with rounded apex, distinct lateral bead and few setae; neck and blade of prosternal process evenly jointed. Abdominal ventrite 6 broadly rounded apically.

Male: Antenna simple (Fig. 28). Protarsomere 4 with medium-sized, slender, slightly curved anterolateral hook-like seta. Protarsomere 5 ventrally with anterior row of 17 and posterior row of 6 relatively long setae (Fig. 1A). Abdominal ventrite 6 with 3-4 very short lateral striae on each side. Median lobe with apical discontinuity and deeply concave, bilobed apex in ventral view (Figs 1B, D). Paramere without notch on dorsal side, with triangular basal part and thin subdistal part, setae inconspicuous, sparse, thin, and relatively short (Fig. 1C).

Holotype: TL-H 3.25 mm, TL 3.6 mm, MW 1.9 mm.

Female: Without evident differences in external morphology from male, except for abdominal ventrite 6 without striae.

Distribution and habitat.

Indonesia: West Papua Province: Kaimana Regency. This species is known only from the type locality (Fig. 53). The species was collected from a small rock pool, without any vegetation (Fig. 54).

Etymology.

The species is named for Andre Skale who collected this species, with our sincere thanks for presenting this interesting species for study. The species name is a noun in the genitive case.