Exocelina manokwariensis, Shaverdo, Helena, Panjaitan, Rawati & Balke, Michael, 2016

Shaverdo, Helena, Panjaitan, Rawati & Balke, Michael, 2016, A new, widely distributed species of the Exocelinaekari-group from West Papua (Coleoptera, Dytiscidae, Copelatinae), ZooKeys 554, pp. 69-85 : 71-74

Taxon classification Animalia Coleoptera Dytiscidae

Exocelina manokwariensis sp. n. Figs 1, 2

Type locality.

Indonesia: West Papua Province: Manokwari Regency, Road Manokwari - Mokwam, 01°00.60'S; 133°53.92'E.

Type material.Holotype: male "Indonesia: Papua, Road Manokwari - Mokwam, 320m, 25./27.i.1990, 01.00.596S 133.53.921E, Balke (BH 01)" (MZB). Paratypes: Manokwari: 12 males, 8 females with the same label as the holotype, two males additionally with green labels "M.Balke 1267", "M.Balke 1282" (MZB, NHMW, ZSM). 6 males, 5 females "Indonesia: Papua, Ransiki - Anggi, 1160m, 30.i.1990, 01.25.536S 134.02.456E, Balke (BH 03)", one male additionally with a green label "M.Balke 1270" (NHMW, ZSM). 2 males, 5 females "IRIAN JAYA, Manokwari Rasiki, Mayuby - Benyas ca. 300-400m, 27.-28.IX.1990, leg. A. Riedel" (NHMW, ZSM). 121 males, 94 females "Indonesia: Papua Barat, Manokwari, Maripi, creek white pebbles, 135m, -0.907576 133.9214718 (BH039)" (MZB, NHMW, ZSM). 2 males "IN: West Papua: Manokwari Reg., on road Manokwari-Kebar, near Munbrani vill., 66 m, 8.V., 00°46'21"S, 133°22'53"E ,, roadside ditch (2015-WP36)" (NHMW, ZSM). 1 male "Indonesia: Papua Barat, Manokwari to Kebar, forest stream, 302m, -0.80058566 133.33216397 (BH023)", one male additionally with a label "M.Balke 6187" (ZSM). 36 males "Indonesia: Papua Barat, Kebar to Aibogar, slow forest stream, 503m, -0,86241595 132,82993928 (BH025)", one male additionally with a label "M.Balke 6190" (MZB, NHMW, ZSM). 2 males, 4 females "Indonesia: Papua Barat, Kebar to Aibogar, forest stream, 942m, -0,89933965 132,7221734 (BH026)", one male additionally with a label "M.Balke 6192" (ZSM). 38 males, 26 females "Indonesia: Papua Barat, Fumato, forest stream, 820m, -0.90427148 132.71981431 (BH027)", four males additionally with labels "M.Balke 6201", "M.Balke 6202", "M.Balke 6203", "M.Balke 6204" (MZB, NHMW, ZSM). 31 males, 22 females "Indonesia: Papua Barat, Fumato to Kebar, forest stream, 674m, -0.88384738 132.73705681 (BH028)" (MZB, NHMW, ZSM). 11 males, 7 females "Indonesia: Papua Barat, Tamrau Mts. N of Kebar, forest stream, 750m, -0,783199 133,072143 (BH033)" (ZSM). 75 males, 154 females "Indonesia: Papua Barat, Tamrau Mts. N of Kebar, forest stream, puddles, 1050m, -0.774519 133.069929 (BH034)" (MZB, NHMW, ZSM). Sorong: 6 males, 9 females "Indonesia: Papua Barat, Sorong-Sausapor, 300m, -0.7629653 131.6177023 (BH041)" (ZSM). 18 males, 21 females "Indonesia: Papua Barat, Sausapor-Fef, 157m, -0.6975004 132.072253 (BH044)" (MZB, NHMW, ZSM).

Additional material.

1 female "Indonesia: Papua Barat, Tamrau Mts. N of Kebar, sandy sunny riverbank", "758m, -0,78387424 133,07218533 (BH032)" (ZSM). 78 females "Indonesia: Papua Barat, Kebar to Aibogar, slow forest stream, 503m, -0,86241595 132,82993928 (BH025)", the females are a mixture of Exocelina manokwariensis sp. n. and Exocelina polita (Sharp, 1882) (MZB, NHMW, ZSM).

Diagnosis.

Beetle small, brown to blackish brown, usually with paler clypeus and pronotal sides or head and pronotum, shiny, with almost invisible dorsal punctation; pronotum with distinct lateral bead; male antennomeres 3-4 strongly enlarged and triangular (3 distinctly larger than 4), 5 distinctly enlarged, 6-8 somewhat enlarged; male protarsomere 4 with medium-sized, slender, evidently curved anterolateral hook-like seta; median lobe with strong submedian constriction in ventral view, apex of median lobe truncate; paramere with notch on dorsal side and subdistal part short and small, with relatively short, thick, and flattened setae.

Description.

Size and shape: Beetle small (TL-H 3.2-3.75 mm, TL 3.45-4.15 mm, MW 1.7-2.05 mm; holotype: TL-H 3.3 mm, TL 3.7 mm, MW 1.75 mm), with oblong-oval habitus, broadest at elytral middle.

Coloration: Head reddish brown to blackish brown, paler on clypeus and vertex; pronotum reddish brown to blackish brown, with paler sides and darker disc; elytra brown to blackish brown, sometimes with brown sutural lines; head appendages and legs yellowish to yellowish red, legs darker distally (Fig. 1). Teneral specimens paler.

Surface sculpture: Head with relatively dense punctation (spaces between punctures 1-3 times size of punctures), evidently finer and sparser anteriorly; diameter of punctures smaller than diameter of cells of microreticulation. Pronotum with extremely sparse and fine punctation, almost invisible. Elytra with punctation finer than on pronotum, indistinct. Pronotum and elytra with weakly impressed microreticulation, dorsal surface shiny. Head with microreticulation stronger. Metaventrite and metacoxa distinctly microreticulate, metacoxal plates with longitudinal strioles and transverse wrinkles. Abdominal ventrites with distinct microreticulation, strioles, and extremely fine, sparse punctation, almost invisible, only slightly 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, less rounded and smooth anteriorly, without anterolateral extensions. Blade of prosternal process lanceolate, relatively elongate, 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: Antennomeres 3-4 strongly enlarged and triangular (3 distinctly larger than 4), 5 distinctly enlarged, 6-8 somewhat enlarged (Fig. 2A); antennomeres 3-7 rugose ventrally. Protarsomere 4 with medium-sized, slender, evidently curved anterolateral hook-like seta. Protarsomere 5 ventrally with anterior row of 12 and posterior row 6 short setae (Fig. 2B). Abdominal ventrite 6 with 8-16 lateral striae on each side, slightly truncate apically. Median lobe with strong submedian constriction in ventral view, apex of median lobe truncate, with relatively short tip in lateral view and relatively asymmetric in ventral view (Fig. 2C, D). Paramere with notch on dorsal side and subdistal part short and small, with numerous, relatively short, thick, and flattened setae (Fig. 2E).

Female: Antennae simple, abdominal ventrite 6 broadly rounded apically, without striae.

Variability.

The species has three subspecies, which are isolated geographically, occurring in restricted regions (Fig. 9). They are very similar morphologically and show (at least on material we have) no much variability in their morphology. Comparisons are given as separate notes after the descriptions.

Here, we discuss the variability of the nominative subspecies, which is more widely distributed (Fig. 9). This subspecies demonstrates variability mainly in shape of the apex of median lobe and setation of the subdistal part of the paramere. The truncate margin of the median lobe apex varies from almost straight (especially specimens from Manokwari) to slightly concave (especially specimens from Kedar, Fumato, Sorong) in lateral view. This variability is observed within and among the populations. Also, number of the subdistal flattened setae of the paramere varies thought it is not possible to estimate that quantitatively, since they are numerous and densely attached. The specimens from western populations have less numerous subdistal flattened setae then specimens from Manokwari.

Comparative notes.

In the Exocelina ekari -group, the new species is similar to the species of the Exocelina polita -complex: Exocelina polita (Sharp, 1882), Exocelina alexanderi Shaverdo, Hendrich & Balke, 2012, Exocelina anggiensis Shaverdo, Hendrich & Balke, 2012, and Exocelina arfakensis Shaverdo, Hendrich & Balke, 2012; see descriptions and illustrations in Shaverdo et al. 2012. From all these species, Exocelina manokwariensis sp. n. can be distinguished by its smaller size (TL-H: 3.1-3.85 mm, MW: 1.65-2.1 mm; for Exocelina polita -complex: TL-H: 3.7-4.3 mm, MW: 2.05-2.3 mm) and apex of the median lobe almost truncate in lateral view (elongate for Exocelina polita -complex, if slightly truncate (in Exocelina alexanderi ), then anntenomeres 3 and 4 of almost equal size). With its very fine dorsal punctation, the new species particularly resembles Exocelina alexanderi , which also has a slightly truncate apex of the median lobe in lateral view, but differs from it by the smaller size and distinctly different shape of the male antennomeres 3 and 4. Exocelina polita also has fine dorsal punctation and it was found together with the new species in two localities. From Exocelina polita , Exocelina manokwariensis sp. n. can be separated by its smaller size, truncate apex of the median lobe in lateral view, and slightly different shape of the male antennomeres 3 and 4.

The nominative subspecies can be distinguished from all the other subspecies by more numerous flattened setae on the subdistal part of the paramere, the slightly shorter median lobe, and the prosternal ridge being less rounded anteriorly. From Exocelina manokwariensis batanta ssp. n. and Exocelina manokwariensis nokensis ssp. n., it can be also separated by slightly darker coloration and the stronger dorsal microreticulation. From Exocelina manokwariensis batanta ssp. n. and Exocelina manokwariensis hendrichi ssp. n., by the more asymmetric apex of the median lobe in ventral view and the smaller subdistal part of the paramere.

Distribution.

Indonesia: West Papua Province: Sorong and Manokwari Regencies (Fig. 9).

Etymology.

The species is named after Manokwari Regency where it is occur. The name is an adjective in the nominative singular.

Ecology.

The species was collected in localities BH 023 and BH 025 together with Exocelina polita in ratios 1:4 and 1:1, respectively.