Exocelina simbaiensis Shaverdo & Balke

Shaverdo, Helena, Sagata, Katayo & Balke, Michael, 2018, Introduction of the Exocelinacasuarina-group, with a key to its representatives and descriptions of 19 new species from New Guinea (Coleoptera, Dytiscidae, Copelatinae), ZooKeys 803, pp. 7-70 : 37-38

21. Exocelina simbaiensis Shaverdo & Balke sp. n. Figs 19, 43

Exocelina undescribed sp. MB3315: Toussaint et al. 2014: supplementary figs 1-4, table 2;

Toussaint et al. 2015: supplementary figs S1-S2, table S3.

Exocelina simbaiensis _New_Guinea_MB3315: Toussaint et al. 2015: supplementary information S5-S6.

Exocelina inengensis MB3309: Toussaint et al. 2015: supplementary figs S1-S2, table S3, and information S5-S6.

Type locality.

Papua New Guinea: Western Highlands Province, Simbai, Ineng River, 05°14.94'S, 144°32.82'E, 2,000 m a.s.l.

Type material.

Holotype: male "Papua New Guinea: Western Highlands, Simbai, Ineng River, 2000m, 27.ii.2007, 05.14.943S 144.32.818E, Kinibel (PNG 135)" (ZSM). Paratypes: 4 males, 9 females with the same label as the holotype, one male with an additional green label "M.Balke 3309" (NHMW, ZSM). 1 male, 1 female "Papua New Guinea: Western Highlands, Simbai area, 2200m, 6.iii.2007, 05.18.752S 144.31.849E, Kinibel (PNG 149)", male additionally with "M.Balke 3316" [green] (ZSM). 2 females "Papua New Guinea: Western Highlands, Simbai area, 2500m, 8.iii.2007, 05.14.202S 144.33.651E, Kinibel (PNG 150)" (NHMW, ZSM). 1 female "M.Balke 3315" [green], "Papua New Guinea: Western Highlands, Jimi Valley, above Sendiap Station, 2000m, 6.iii.2007, 05.19.314S 144.31.266E, Kinibel (PNG 148)" (ZSM).

Description.

Body size and form: Beetle small to medium-sized: TL-H 3.3-4.15 mm, TL 3.65-4.5 mm, MW 1.8-2.15 mm (holotype: TL-H 3.9 mm, TL 4.25 mm, MW 2.0 mm), with rather oblong habitus.

Coloration: Dark brown to piceous, sometimes with reddish pronotum. Head dark brown to piceous, paler anteriorly. Pronotum dark brown to piceous, with reddish brown lateral sides and sometimes anteriorly and narrowly posteriorly. Elytra dark brown to piceous, sometimes with narrow reddish sutural lines. Head appendages and legs proximally yellowish red, legs distally darker, reddish (Fig. 19).

Surface sculpture: Matt dorsally. Head with dense punctation (no spaces between punctures or spaces 2 times size of punctures), finer and sparser anteriorly; diameter of punctures equal to diameter of cells of microreticulation. Pronotum and elytra with slightly sparser and finer punctation than on head. Head, pronotum and elytra with strongly impressed microreticulation. Metaventrite and metacoxae distinctly microreticulate, metacoxal plates with longitudinal strioles and transverse wrinkles. Abdominal ventrites with distinct microreticulation, strioles, and fine, sparse but distinct punctation.

Structures: Pronotum with distinct lateral bead. Its lateral sides with distinct longitudinal impressions. 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: Antennomere simple, slightly stout (Fig. 19). Protarsomere 4 with anterior angle slightly expanded, with large, thick, strongly curved anterolateral hook-like seta. Protarsomere 5 long and narrow, slightly concave ventrally, with anterior band of ca 40 and irregular posterior row of 17 relatively long setae (Fig. 43D). Median lobe in lateral view slightly curved, its apex thickened, bent downwards; in ventral view, slightly broadened medially, with broadly pointed apex. Paramere very slightly concave on dorsal side and with dense setae on subdistal part; proximal setae inconspicuous (Fig. 43 A–C). Abdominal ventrite 6 with 7-12 lateral striae on each side.

Female: Without evident differences in external morphology from males, except for not modified protarsi and abdominal ventrite 6 without striae.

Variability. The specimens from Ineng River are larger: TL-H 3.5-4.15 mm; remaining specimens: TL-H 3.3-3.7 mm. In addition, the population from Ineng River shows variability in how strongly apex of the median lobe bent downwards in lateral view.

Affinities.

Exocelina simbaiensis sp. n. is similar to E. yoginofi sp. n. in body form, size, and coloration, but differs from it in distinctly stronger punctation and microreticulation and in thickened apex of the median lobe.

Distribution.

Papua New Guinea: Western Highlands Province, near Simbai (Fig. 50).

Etymology.

The species is named after Simbai area. The name is an adjective in the nominative singular.