Exocelina adelbertensis 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 : 11

1. Exocelina adelbertensis Shaverdo & Balke sp. n. Figs 14, 38

Exocelina undescribed sp. MB1297: Toussaint et al. 2014: supplementary figs 1-4, table 2;

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

Exocelina adalbert _New_Guinea_MB1297: Toussaint et al. 2015: supplementary information S5-S6.

Type locality.

Papua New Guinea: Madang Province, Adelbert Mts, Keki to Sewan, 04°41.80'S, 145.25.46'E, 650 m a.s.l.

Type material.

Holotype: male "Papua New Guinea: Madang, Adalbert [sic!] Mts., Keki to Sewan, 650m, 7.v.1994, 04.41.802S 145.25.460E, Balke (PNG 54)", "M.Balke 1297" [green] (ZSM).

Description.

Body size and form: Beetle small: TL-H 3.1 mm, TL 3.4 mm, MW 1.9 mm, with broader, oval habitus.

Coloration: Brownish, with head and pronotum paler. Head reddish brown, darker posterior to eyes. Pronotum reddish brown on sides, dark brown on disc. Elytra brown. Head appendages yellowish red, legs reddish, distally darker, especially metathoracic legs (Fig. 14).

Surface sculpture: Submatt dorsally. As in E. sumokedi sp. n., except for more strongly impressed microreticulation.

Structures: Pronotum with lateral bead. Its lateral sides with longitudinal impressions. Base of prosternum and neck of prosternal process with distinct ridge, rounded anteriorly. Blade of prosternal process lanceolate, relatively broad, slightly convex, with distinct lateral bead and few setae. Abdominal ventrite 6 slightly truncate.

Male: Antennae simple (Fig. 14). Protarsomere 4 with medium-sized, thick, curved anterolateral hook-like seta. Protarsomere 5 long and narrow, with anterior row of 17 and posterior row of 6 relatively short, thin setae (Fig. 38D). Median lobe in lateral view slightly curved, with thickened, angulate apex; in ventral view, subparallel, very slightly narrowed distally, and with broadly truncate apex. Paramere slightly concave on dorsal side and with dense setae on subdistal part; proximal setae sparser (Fig. 38 A–C). Abdominal ventrite 6 with 4-5 lateral striae on each side.

Female: Unknown.

Affinities.

Exocelina adelbertensis sp. n. is very similar to E. sumokedi sp. n. and E. bewani sp. n. but it has slightly more strongly impressed microreticulation, therefore, dorsal surface is distinctly less shiny. Median lobe is more thickened, similar to that of E. sumokedi sp. n. but its apex is curved downwards and with stronger terminal angulation. The species is also similar to E. cyclops sp. n., E. pseudopusilla sp. n., and E. pusilla sp. n., see their “Affinities” and the “Key”.

Distribution.

Papua New Guinea: Madang Province. The species is known only from the type locality (Fig. 50).

Etymology.

The species is named after Adelbert Mountains. The species name is an adjective in the nominative singular.