Exocelina oraia Shaverdo, Surbakti & Balke, 2021

Shaverdo, Helena, Surbakti, Suriani, Sumoked, Bob & Balke, Michael, 2021, Seven new species of the Exocelina ekari group from New Guinea central and coastal mountains (Coleoptera, Dytiscidae, Copelatinae), ZooKeys 1026, pp. 45-67 : 45

Exocelina oraia Shaverdo, Surbakti & Balke sp. nov. Figures 13-14 , 15

Exocelina nr. irianensis #6520: Toussaint et al. 2021: figs 3-6.

Type locality.

Indonesia: Papua Province, Puncak Jaya Regency, Puluk area , 03°39'37.0"S, 137°31'14.7"E, 1320 m a.s.l.

Type material.

Holotype: male " Indonesia: Papua, Wano Land, Puluk , 1320m, 1.ix.2014, -3.660272 137.5207436, Bennji (Pap020)" ( MZB). Paratypes: 14 males, 10 females with the same label as the holotype, one male with an additional label “6520” [green text] ( MZB, KSP) .

Description.

Body size and form: Beetle small to medium-sized: TL-H 3.45-3.85 mm, TL 3.8-4.25 mm, MW 1.85-2.1 mm (holotype: TL-H 3.6 mm, TL 4 mm, MW 1.95 mm), with oblong-oval habitus (Fig. 13 ).

Colouration: Dorsally piceous (Fig. 13 ). Head piceous, with slightly paler, dark brown, anterior margin; pronotum piceous, with reddish brown anterior angles and dark brown lateral sides; elytra uniformly piceous; head appendages and proximal part of legs yellowish brown, legs distally brown. Teneral specimens paler.

Surface sculpture: Shiny dorsally, with invisible elytral punctation and weakly impressed microreticulation. Head with relatively sparse punctation (spaces between punctures 1-3 times size of punctures), evidently finer and sparser anteriorly and posteriorly; diameter of punctures smaller than diameter of cells of microreticulation. Pronotum with distinctly finer, sparser, and more evenly distributed punctation than on head, often inconspicuous. Elytra with extremely sparse and fine punctation, often invisible. Pronotum and elytra with weakly impressed microreticulation; head with microreticulation much stronger. Metaventrite and metacoxa distinctly but weakly microreticulate, metacoxal plates with longitudinal strioles and very weak transverse wrinkles. Abdominal ventrites with distinct but weak microreticulation, strioles, and extremely fine and sparse, often invisible punctation, more distinct on abdominal ventrite 6.

Structures: Pronotum without lateral bead, in some specimens (especially characteristic for females) with bead traces or even with narrow bead on lateral sides of pronotum. 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 lateral bead and few setae. Abdominal ventrite 6 broadly rounded.

Male: Antenna modified (Fig. 13 ): antennomeres 3 and 4 strongly enlarged, distinctly larger than other antennomeres, antennomere 5 distinctly enlarged, 6-9 stout. Pro- and mesotarsomeres 1-3 narrow. Protarsomere 4 narrow, with medium-sized, slightly curved anterolateral hook-like seta. Protarsomere 5 ventrally with anterior row of nine and posterior row of three short setae (Fig. 14A ). Median lobe with distinctly discontinuous outline; in lateral view, almost straight, with curved downwards, rather narrow, sharply pointed apex; in ventral view, with strong submedian constriction, distal part distinctly narrower than proximal one, apex symmetrical, slightly evenly concave (Fig. 14B, C ). Paramere with strong notch on dorsal side and subdistal part short and small; subdistal setae relatively short, thick, flattened; proximal setae more numerous, dense, hair-like, weaker than subdistal ones (Fig. 14D ). Abdominal ventrite 6 with 4-8 lateral striae on each side.

Female: Pro- and mesotarsi not modified. Abdominal ventrite 6 without lateral striae. Bead traces or even with narrow bead on lateral margins pronotum present in majority of females.

Affinities.

The species evidently belongs to the E. ekari group due to the discontinuous outline of its median lobe. The new species is very similar to E. irianensis Shaverdo et al., 2012 and E. wondiwoiensis Shaverdo et al., 2012 in general appearance, modified male antennae, and structure of the male genitalia, but differs from them in shape of median lobe and setation of the paramere. Additionally, the species shows a stronger tendency to have the lateral bead of pronotum.

Distribution.

Indonesia: Papua Province. This species is known only from the type locality (Fig. 15 ) .

Habitat.

The specimens were collected from small forest creeks.

Etymology.

The species name Exocelina oraia derives from Greek ωραίος (feminine ωραία) meaning nice, lovely. The name is an adjective in the nominative singular.

Figures

Figure 15. Map of the western part of New Guinea showing the species distribution.

Figures 13, 14. Exocelina oraia sp. nov., holotype 13 habitus and colouration 14 male structures A right protarsomeres 4 and 5 in ventral view B median lobe in ventral view C median lobe in lateral view D right paramere in external view.