Exocelina bacchusi herzogensis Shaverdo & Balke

Shaverdo, Helena, Surbakti, Suriani, Warikar, Evie L., Sagata, Katayo & Balke, Michael, 2019, Nine new species groups, 15 new species, and one new subspecies of New Guinea diving beetles of the genus Exocelina Broun, 1886 (Coleoptera, Dytiscidae, Copelatinae), ZooKeys 878, pp. 73-143 : 73

6a. Exocelina bacchusi herzogensis Shaverdo & Balke ssp. nov. Figs 17 , 23

Exocelina undescribed sp. MB1383: Toussaint et al. 2014: supplementary figs 1-4, tab. 2; Toussaint et al. 2015: supplementary figs S1, S2, tab. S3, and information S5, S6.

Type locality.

Papua New Guinea: Central Province, Woitape, 08°33.17'S, 147°15.48'E, 1500 m a.s.l.

Type material.

Holotype: male "Papua New Guinea: Central, Woitape, 1500m, i.2008, [08°] 33.178S 147.15.481E, Posman (PNG 167)", "DNA M.Balke 3401" [green] (ZSM). Paratypes: 1 male, 2 females with the same labels as the holotype (NHMW, ZSM). 1 male "Papua New Guinea: Morobe, Wagau, Herzog Mts., 1150m, 19.xi.2006, 06.51.067S 146.48.068E, Balke & Kinibel (PNG 102)", "DNA M.Balke 1383" [green] (ZSM).

Description.

Body size and form: Beetle small: TL-H 3.4-3.6 mm, TL 3.8-4.0 mm, MW 1.85-2.0 mm (holotype: TL-H 3.6 mm, TL 4.0 mm, MW 2.0 mm), with oblong-oval habitus.

Colouration: Yellow reddish to brown. Head reddish brown to brown, dark brown posterior to eyes. Pronotum yellowish reddish, with small dark area on disc or brown, with paler sides. Elytra yellow reddish to brown. Head appendages and legs proximally yellowish, legs distally darker, reddish brown ( Fig. 17 ). Teneral specimen yellowish.

Surface sculpture: Shiny dorsally, with very fine punctation and weakly impressed microreticulation. Elytral punctation and microreticulation finer then in nominotypical subspecies. Elytral punctation usually invisible.

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, slightly convex, with distinct bead and few setae laterally. Abdominal ventrite 6 slightly truncate.

Male: Protarsomere 4 with anterolateral seta rather long and thing, evenly curved, smaller than more laterally situated large seta. Protarsomere 5 ventrally with anterior band of more than 60 and posterior row of ten relatively long setae ( Fig. 23D ). Abdominal ventrite 6 with 6-8 lateral striae on each side. Median lobe simple, evenly tapering towards apex in lateral and ventral views; in lateral view, apex elongate, thin, with slightly enlarged, rounded tip ( Fig. 23A, B ). Paramere as in Fig. 23C .

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

Variability.

Colouration of the specimens from Woitape distinctly paler, yellowish; the specimen form Wagau much darker, brown.

Affinities.

From the nominotypical subspecies, it can be distinguished by shinier dorsal surface, shorter setae of male protarsomere 4, and by apex of the median lone elongate, thinner, with slightly enlarged tip. The further study is necessary to confirm the status of this taxon, which seems to replace the nominotypical subspecies in the Papuan Peninsula.

Distribution.

Papua New Guinea: Morobe and Central Provinces ( Fig. 25 ).

Etymology.

The subspecies is named after Herzog Mts., where the subspecies was the first time discovered. The name is an adjective in the nominative singular.

Figures

Figure 25. Map of the eastern part of New Guinea showing distribution of the species of the E. bacchusi group.

Figures 12 - 17. Habitus and colouration 12 Exocelina oiwa sp. nov. 13 E. akameku sp. nov. 14 E. erteldi (Balke, 1998) 15 E. oksibilensis sp. nov. 16 E. bacchusi (Balke, 1998) 17 E. bacchusi herzogensis sp. nov.

Figures 22, 23. 22 Exocelina bacchusi (Balke, 1998), paratype (Madang, Damanti) 23 E. bacchusi herzogensis ssp. nov. A median lobe in ventral view B median lobe in lateral view C paramere in external view D male protarsomeres 4 - 5 in ventral view.