Six new species of the genus Exocelina Broun, 1886 from Wano Land, New Guinea (Coleoptera, Dytiscidae, Copelatinae)

Abstract Six new species of New Guinea Exocelina Broun, 1886 are described in this paper: E. iratoi sp. n., E. likui sp. n., E. pui sp. n., E. pulukensis sp. n., E. tomhansi sp. n., and E. wigodukensis sp. n. Although different morphologically, together with Exocelina ascendens (Balke, 1998), E. bagus (Balke & Hendrich, 2001), and E. ransikiensis Shaverdo, Panjaitan & Balke, 2016, they are found to form a monophyletic clade and be closely related to representatives of the E. ekari-group, based on preliminary analysis of sequence data. An identification key to the species is provided, and important diagnostic characters are illustrated. The present data on the species’ distribution show that most of them are local endemics.


Introduction
spine-like setae (Fig. 11D); median lobe evenly curved, pointed in lateral view and evenly tapering, with broadly pointed apex in ventral view, on both lateral sides with numerous fine setae situated linearly on anterior half of distal part of median lobe; paramere robust, with notch on dorsal side and very dense, strong setae on subdistal part; proximal setae sparse and fine ( Fig.11A-C). For complete description, see .
Distribution. Papua: Pegunungan Bintang Regency. The species is known only from the type material (Fig. 19). Diagnosis. Beetle medium-sized, oblong-oval, piceous, with brown sides of pronotum, dorsal punctation inconspicuous, microreticulation weakly impressed; pronotum without lateral bead; male antennae simple; male protarsomere 4 with large, thick, strongly curved anterolateral hook-like seta; median lobe evenly curved, pointed in lateral view and evenly tapering, with broadly pointed apex in ventral view, on both lateral sides with numerous short, thick setae situated on anterior half of distal part of median lobe; paramere robust, with notch on dorsal side and very dense, strong setae on subdistal part; proximal setae sparse and fine. The new species is very similar to E. ascendens in shape of the median lobe and in shape and setation of the paramere but distinctly differs from it having smaller body size, shiny dorsal surface due to much more weakly impressed microreticulation, larger anterolateral hook-like seta on the male protarsomere 4, longer setae of the male protarsomere 5 and, especially in absence of the pronotal bead.
Surface sculpture: Head with sparse punctation (spaces between punctures 2-3 times size of punctures), evidently finer and sparser anteriorly; diameter of punctures smaller than to almost equal to diameter of cells of microreticulation. Pronotum with much sparser and finer punctation than head. Elytra with extremely sparse and fine punctation, almost invisible. Pronotum and elytra with slightly impressed microreticulation, dorsal surface shiny. Head with microreticulation stronger. Metaventrite and metacoxae distinctly microreticulate, metacoxal plates with longitudinal strioles and transverse wrinkles. Abdominal ventrites with distinct microreticulation, strioles, and very fine and sparse punctation.
Structures: Pronotum without lateral bead. Base of prosternum and neck of prosternal process with distinct ridge, smooth and slightly rounded anteriorly. Blade of prosternal process lanceolate, narrow, slightly convex, with distinct lateral bead and few setae; neck and blade of prosternal process evenly jointed. Abdominal ventrite 6 broadly rounded or slightly truncate apically.
Male: Antenna simple (Fig. 4). Pro-and mesotarsomeres 1-3 not dilated. Protarsomere 4 cylindrical, narrow, with large, thick, strongly curved anterolateral hooklike seta. Protarsomere 5 ventrally with anterior band of 26 and posterior row of six relatively long, not pointed setae (Fig. 12D). Median lobe evenly curved, pointed in lateral view and evenly tapering, with broadly pointed apex in ventral view, on both lateral sides with numerous short, thick setae situated on anterior half of distal part of median lobe. Paramere robust, with notch on dorsal side; subdistal part large and elongate, with very dense, strong setae; proximal setae sparse and fine ( Fig. 12A Distribution. Papua: Puncak Jaya and Puncak Regencies (Fig. 19). Etymology. The species is named in honour of helicopter pilot Tom Hans who has served the Papuan people for many years. The name is a noun in the genitive case.
Distribution. Papua: Nabire Regency. The species is known only from the Mount Gamey area (Fig. 19). Diagnosis. Beetle small, oblong-oval, piceous, with dark brown head and pronotum, dorsal punctation inconspicuous, microreticulation weakly impressed; pronotum without lateral bead; male antennae simple; male protarsomere 4 with large, thick, strongly curved anterolateral hook-like seta; apex of median lobe with three small prolongations; paramere without dorsal notch, with long, rather dense, thin setae, situated along dorsal margin, not clearly divided into subdistal and proximal.

Exocelina iratoi-group
In oblong-oval shape of the body, fine dorsal sculpture, and absence of the pronotal bead, the species is similar to many small species of the E. ekari-group but distinctly differs from them in shape of the median lobe and paramere.
Surface sculpture: Head with sparse punctation (spaces between punctures 2-3 times size of punctures), evidently finer and sparser anteriorly; diameter of punctures smaller than to almost equal to diameter of cells of microreticulation. Pronotum with much sparser and finer punctation than head. Elytra with extremely sparse and fine punctation, inconspicuous. Pronotum and elytra with slightly impressed microreticulation, dorsal surface shiny. Head with microreticulation stronger. Metaventrite and metacoxae distinctly microreticulate, metacoxal plates with longitudinal strioles and transverse wrinkles. Abdominal ventrites with distinct microreticulation, strioles, and very fine and sparse punctation.
Structures: Pronotum without lateral bead. Base of prosternum and neck of prosternal process with distinct ridge, smooth and rounded anteriorly. Blade of prosternal process lanceolate, relatively narrow, slightly convex, with distinct lateral bead and few setae; neck and blade of prosternal process evenly jointed. Abdominal ventrite 6 broadly rounded apically.
Distribution. Papua: Puncak Regency. The species is known only from the type locality (Fig. 19).
Iratoi is a mixed village of both Edofi and Wano people. It is located just beyond the foot hills coming out of Wano land at the northwestern border of their traditional territory. This area is quite low at an elevation of ca. 200 m, which offers many opportunities to easily access the many small streams and puddles which Exocelina inhabits.
Etymology. The name refers to Iratoi, the type locality. The name is a noun in the nominative singular standing in apposition. Diagnosis. Beetle small, oblong, dark brown to piceous, dorsal punctation dense and coarse, microreticulation distinctly impressed; pronotum without lateral bead; male antennae simple; male protarsomere 4 cylindrical, narrow, with large, thick, strongly curved anterolateral hook-like seta; median lobe slightly curved, with broadly pointed apex in lateral view and abruptly narrowed apically, with apex truncate in ventral view; paramere without dorsal notch, with subdistal setae very dense, strong, long and proximal setae very sparse, thin, small, weakly visible.

Exocelina likui
In shape of median lobe, the species resembles E. takime ) but distinctly differs from it in absence of the pronotal bead and strong dorsal sculpture. From E. pui sp. n., it differs in dense and coarse dorsal punctation and in having medial lobe apically more pointed in lateral view, without lateral setae.
Surface sculpture: Head with dense, coarse punctation (spaces between punctures 1-2 times size of punctures), finer anteriorly and posteriorly; diameter of punctures equal to diameter of cells of microreticulation. Pronotum with slightly sparser punctation than head. Elytra with dense, coarse punctation, coarser than on pronotum. Pronotum and elytra with distinctly impressed microreticulation, dorsal surface submatt. Head with microreticulation stronger. Metaventrite and metacoxae distinctly microreticulate, with sparse but distinct punctation, metacoxal plates with longitudinal strioles and transverse wrinkles. Abdominal ventrites with distinct microreticulation, strioles, and sparse, coarse punctation, especially on four last abdominal ventrites.
Structures: Pronotum without lateral bead. Base of prosternum and neck of prosternal process with distinct ridge, smooth, broadly rounded anteriorly. Blade of prosternal process lanceolate, relatively narrow, very slightly convex, with distinct lateral bead and few setae; neck and blade of prosternal process evenly jointed. Abdominal ventrite 6 broadly rounded apically.
Distribution. Papua: Puncak Jaya Regency. The species is known only from the type locality (Fig. 19).
Etymology. The species is named after Michael Wild's best Wano friend Liku who grew up at Iratoi and hunted many times in the area where the species was collected. The name is a noun in the genitive case. Diagnosis. Beetle small, dark brown to piceous, with paler anterior part of head and sides of pronotum, dorsal punctation fine, microreticulation distinctly impressed; pronotum without lateral bead; male antennae simple; male protarsomere 4 cylindrical, narrow, with large, thick, strongly curved anterolateral hook-like seta; median lobe slightly curved, with truncate apex in lateral view and abruptly narrowed apically, with apex concave in ventral view, having short, thick subdistal setae laterally; paramere without dorsal notch, with subdistal setae dense, strong, long and proximal setae very sparse, thin, small, weakly visible.
In habitus shape, coloration, and absence of the pronotal bead, E. pui sp. n. strongly resembles the small species from the E. ekari-group (one of them is its co-occurring species) but it distinctly differs from them in having different shape of the median lobe and paramere. The shape of the median lobe is very similar to that of E. rivulus , also a co-occurring species, from which E. pui sp. n. can be easily distinguished in its smaller size and absence of the pronotal bead. From E. likui sp. n., it differs in distinctly finer dorsal punctation and in having median lobe truncate in lateral view, with lateral setae.
Surface sculpture: Head with fine and relatively dense punctation (spaces between punctures 1-3 times size of punctures), finer and sparser anteriorly; diameter of punctures almost equal to diameter of cells of microreticulation. Pronotum with sparser and finer punctation than head. Elytra with very sparse and fine punctation, often inconspicuous. Pronotum and elytra with distinctly impressed microreticulation, dorsal surface less shiny. Head with microreticulation stronger. Metaventrite and metacoxae distinctly microreticulate, metacoxal plates with longitudinal strioles and transverse wrinkles. Abdominal ventrites with distinct microreticulation, strioles, and very fine and sparse punctation.
Structures: Pronotum without lateral bead. Base of prosternum and neck of prosternal process with distinct ridge, smooth, broadly rounded anteriorly. Blade of prosternal process lanceolate, relatively narrow, very slightly convex, with distinct lateral bead and few setae; neck and blade of prosternal process evenly jointed. Abdominal ventrite 6 broadly rounded apically.
Distribution. Papua: Puncak Regency. The species is known only from the type locality (Fig. 19).
Etymology. The species is named after a young Wano man Pu, who grew up in Puluk and accompanied his father (now deceased) on many hunting trips in the area where this species was collected. The name is a noun in the genitive case. Diagnosis. Small, with oblong with subparallel sides to broadly oval habitus; coloration red to dark brown; dorsal surface with strong punctation and microreticulation, matt; pronotum with distinct lateral bead; male antennomeres simple; male protarsomere 4 with large, thick, strongly curved anterolateral hook-like seta; median lobe slightly tapering in ventral view and with curved apex in lateral view; paramere without notch on dorsal side, with thin, sparse, inconspicuous setae. For the complete description, please see Shaverdo et al. (2016d).
Notes on morphological variability. Recently discovered beetles from the western part of Manokwari Regency show distinct differences in the size, body shape, and coloration from those of the type series. They are larger: TL-H 3.25-3.7 mm (representatives of the type series: TL-H 2.85-3.2 mm) and have darker coloration: dark brown, with paler anterior margin of the head and sides of the pronotum. Very interesting is the variability of the body shape: the beetles from Ransiki and Nabire are oblong, with subparallel sides, the beetles from the Tamrau Mountains (localities BH023, BH033, and BH034) also have this body shape but they are distinctly larger, whereas the beetles from Kebar-Aibogar have a more rounded habitus, which is distinctly broadly oval in the specimen from Fumato. That represents almost gradual change of the body shape from oblong, parallel-sided in the east to broadly oval in the west. No variability has been found in the shape of the median lobe and paramere, or in the surface sculpture. Therefore, at present, we treat all new material as E. ransikiensis bearing in mind that more material is needed for a final conclusion.

Exocelina wigodukensis-group
This group includes two species, which have one unique character: few (usually three) last subdistal setae of the paramere, standing isolated, are modified having indistinct or very evident basal prolongation (Figs 17C, 18C). Such a modification is also characteristic for some subdistal setae, which are in the "brash" (see in the description below), but it is less evident. Diagnosis. Beetle medium-sized, piceous, with pronotum paler anteriorly and laterally, dorsal punctation dense and coarse, microreticulation strongly impressed; pronotum without lateral bead; male antennae evidently modified: antennomeres 3-4 and 9-10 stout, antennomeres 5-8 distinctly enlarged, larger than other antennomeres; protarsomere 4 with large, thick, strongly curved anterolateral hook-like seta; protarsomere 5 slightly concave ventrally; median lobe slightly curved, narrow, with apex slightly curved downwards as very small "beak" in lateral view; with slightly concave apex and subparallel sides in ventral view; paramere without dorsal notch, subdistal setae numerous, long, dense, strong, proximal setae thin and sparse, inconspicuous.

Exocelina wigodukensis
The species is similar to E. pulukensis sp. n. but distinctly differs from it in having more strongly modified male antennae, thinner and stronger curved apex of the median lobe in lateral view, and three isolated setae of the paramere with very small basal prolongations. Also see under E. pulukensis sp. n.
Surface sculpture: Head with dense punctation (spaces between punctures 1-2 times size of punctures), evidently finer and sparser anteriorly; diameter of punctures almost equal to diameter of cells of microreticulation. Pronotum with sparser and finer punctation than head. Elytra with coarse and dense punctation, coarser than on pronotum. Pronotum and elytra with strongly impressed microreticulation, dorsal surface matt. Head with microreticulation stronger. Metaventrite and metacoxae distinctly microreticulate and punctate, metacoxal plates with longitudinal strioles and transverse wrinkles. Abdominal ventrites with distinct microreticulation, strioles, and distinct sparse punctation.
Structures: Pronotum without lateral bead. Base of prosternum and neck of prosternal process with distinct ridge, slightly rounded anteriorly, with small transverse wrinkles. Blade of prosternal process lanceolate, relatively broad, with distinct lateral bead, with small transverse wrinkles on both sides along lateral bead and convex and smooth middle; neck and blade of prosternal process evenly jointed. Abdominal ventrite 6 broadly rounded or slightly truncate apically.
Variability. There are three specimens (see "Additional material") of much smaller size (TL-H 3.8-3.95 mm, TL 3.2-3.6 mm, MW 1.85-1.9 mm; for E. wigodukensis sp. n. from Mokndoma: TL-H 4.05-4.35 mm, TL 4.3-4.7 mm, MW 2.1-2.3 mm) and with slightly different shape of the median lobe (less curved downwards apex) among the beetles of the population from Mokndoma. More material from the region is necessary to conclude whether two distinct but very similar species occur here or it is just a matter of variability.
Distribution and habitat. Papua: Puncak Jaya Regency. The species is known from two localities: Wigoduk and Mokndoma (Fig. 19).
At 2150 m, Mokndoma is an area of high cloud forest. Although this area lies within the territory of the Wano tribe, the word Mokndoma is from the neighboring Dem language. Mok means "flat" and Ndoma means "ground". So the name of the place is literally "Flat ground". This is the current home of the second author. In many places at Mokndoma, the ground is boggy with lots of moss and tannin stained streams and ponds. It is an almost mystical place featuring moss tunnels, bog grass, mountain rhododendrons, woody epiphytes, wild ginger and many shrubby small coniferous trees. Upon leaving the open flat area and heading into the thick jungle to the east, west or south, one finds many small streams (Fig. 1) and puddles in which Exocelina beetles abound.
Wigoduk is the name of a valley system to the northeast of Mokndoma. It is about onehour hike from the second author's house site in Mokndoma. Wigoduk is located at 1800 m, right on the eastern bank of a wide bend in the Nggoduk River (Fig. 2). The Nggoduk River is approximately 6-8 m wide and most times only knee deep. In the Wigoduk valley, it meanders along, but upon exiting the valley, turns turbulent as it hurries down the mountain to the larger Yamo River at the bottom of a large east to west running valley at about 1000 m elevation. The Nggoduk River banks are made of smooth rocks and pebbles, a superb site for collecting many different Co-leoptera. Exocelina beetles are found around this area and on the trail from Mokndoma to Wigoduk in many very small streams and puddles.
Etymology. The name refers to Wigoduk, the type locality. The name is an adjective in the nominative singular. Diagnosis. Beetle medium-sized, piceous, with pronotum paler anteriorly and laterally, dorsal punctation dense and coarse, microreticulation strongly impressed; pronotum without lateral bead; male antennomeres 3-10 stout; protarsomere 4 with large, thick, strongly curved anterolateral hook-like seta; protarsomere 5 slightly concave ventrally; median lobe slightly curved, with apex rounded, slightly curved downwards in lateral view, in ventral view narrowed subdistally, with subparallel sides and slightly asymmetrical, concave apex; paramere without dorsal notch, subdistal setae numerous, long, dense, strong, three isolated setae of the paramere with distinct basal prolongations, proximal setae thin and sparse, inconspicuous.

Exocelina pulukensis
The species is similar to E. wigodukensis sp. n. but differs from it in having less modified antennae, different shape of the median lobe (broader and without apical "beak" in lateral view and narrowed subdistally and with slightly asymmetrical apex in ventral view), and in having three isolated setae of the paramere with distinct basal prolongations.
Variability. The males from the localities Pap020 and Pap024 (see "Additional material") have thicker and shorter median lobe, with its apex distinctly broader in lateral view and more concave in ventral view. More material from the region is necessary to conclude whether two distinct but very similar species occur here or it is just a matter of variability.
At Puluk (1370 m), there are three permanent Wano families living, and near their houses, the small trees and bushes are kept trimmed back. The soil is dark, and very fertile. Off into the jungle, around their houses in a circumference of approximately 30-50 m, secondary growth is always encroaching on the hamlet site. Outwards to 250 m beyond the secondary growth, the jungle is lush, but somewhat thinned out, since they clear out smaller trees, and underbrush for firewood and materials for building houses and gardens. Their gardens are out beyond that, and are roughly made and maintained. Beyond that, the jungle is pristine. Just in the jungle to the west of the hamlet site is a small stream where Exocelina abound (the villagers nearest drinking and bathing source). To the north of the hamlet in the mountains, there are many smaller streams and puddles coming teeming with beetles.
Etymology. The name refers to Puluk area where the species were found. The name is an adjective in the nominative singular.