Exocelina hudsoni 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 hudsoni Shaverdo, Surbakti & Balke sp. nov. Figures 9 , 10 , 15

Type locality.

Indonesia: Papua Province, Jayapura Regency, Cyclops Mts , 1880 m a.s.l.

Type material.

Holotype: male " Indonesia: Papua, Cyclops Mountains , below summit, 1880m, ii.201, Sentani Naturalist Club (Pap70)" ( MZB) .

Paratypes: 7 females with the same label as the holotype ( MZB, KSP) .

Description.

Body size and form: Beetle small to medium-sized: TL-H 3.4-3.75 mm, TL 3.75-4.2 mm, MW 1.8-2.05 mm (holotype: TL-H 3.4 mm, TL 3.8 mm, MW 1.8 mm), with oblong-oval habitus (Fig. 9 ).

Colouration: Dorsally piceous, with paler head and pronotum (Fig. 9 ). Head piceous in posterior half and dark brown in anterior half; pronotum piceous on disc, sometimes narrowly, and brown to dark brown on sides, yellowish red to reddish brown at anterior angles; elytra piceous, with brown to dark brown sutural lines; head appendages and proximal part of legs yellowish brown, legs distally reddish brown.

Surface sculpture: Submatt dorsally, with inconspicuous elytral punctation and strongly impressed dorsal microreticulation. Head with sparse central punctation (spaces between punctures 1-4 times size of punctures), denser towards eyes; diameter of punctures smaller than diameter of cells of microreticulation; punctation relatively shallow. Pronotum with distinctly finer, sparser, and more evenly distributed punctation than on head. Elytra with very sparse and fine punctation, almost invisible. Dorsal surface with strongly impressed microreticulation, microreticulation weaker on elytra and stronger on pronotum and head. Metaventrite and metacoxa distinctly but weakly microreticulate, metacoxal plates with longitudinal strioles and very weak transverse wrinkles. Abdominal ventrites with weak microreticulation, strioles, and almost invisible punctation.

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 broad, convex, with distinct lateral bead and few setae. Abdominal ventrite 6 broadly rounded.

Male: Antennomeres 4-10 slightly but distinctly enlarged (Fig. 9 ). Pro- and mesotarsomeres 1-3 not dilated, narrow. Protarsomere 4 cylindrical, narrow, with large, thick, strongly curved anterolateral hook-like seta. Protarsomere 5 ventrally with anterior row of eleven and posterior row of five short setae (Fig. 10A ). Median lobe with distinctly discontinuous outline; in lateral view, almost straight, with apex broad, curved downwards, and pointed at tip; in ventral view, with distinct submedian constriction, distal part narrower than proximal one, apex asymmetrical, narrowly concave (Fig. 10B, C ). Paramere with strong notch on dorsal side, with median notch tip sharply pointed, and subdistal part large and elongate; subdistal setae long, dense, curved at apex, and of two different types: upper setae thinner, more hair-like and lower setae thick and flattened; proximal setae hair-like, more inconspicuous than subdistal ones (Fig. 10D ). Abdominal ventrite 6 broadly rounded, with nine lateral striae on each side.

Female: Antennomeres 4-10 stout. Pro- and mesotarsi not modified. Abdominal ventrite 6 without lateral striae.

Affinities.

The species evidently belongs to the E. ekari group due to the discontinuous outline of its median lobe. The species is very similar to E. brahminensis and E. apistefti sp. nov. in general structure of male genitalia, especially in the sharply pointed median notch tip of paramere, but differs from them in submatt dorsal surface due to stronger microreticulation, presence of pronotal bead, enlarged antennomeres 4-10, shape of the median lobe, and setation of the paramere.

Distribution.

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

Habitat.

The specimens were collected from small puddles at low spot of a small ravine.

Etymology.

This species is named after Hudson Wild, a most dedicated naturalist and community worker in Papua. The name is a noun in the genitive case.

Figures

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

Figures 9, 10. Exocelina hudsoni sp. nov., holotype 9 habitus and colouration 10 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.