Exocelina kailaki 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

12. Exocelina kailaki Shaverdo & Balke sp. nov. Figs 28 , 32

Exocelina undescribed sp. MB3409: 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, Kailaki, 09°24.134'S, 147°33.521'E, 827 m a.s.l.

Type material.

Holotype: male "Papua New Guinea: Central, Moroka area, Kailaki, 827 m, 26.x.2009, 9.24.134S 147.33.521E, Sagata (PNG225)" (ZSM). Paratypes: 14 males, 27 females with the same label as the holotype (NHMW, ZSM). 3 males, 5 females "Papua New Guinea Central, Moroka, Kailaki Wareaga, 760m, 27x2009 9.25.424S 147.31.068E Sagata (PNG227)" (ZSM). 1 male "Stn. No. 200B", "PAPUA: Musgrave River, Sogeri Plateau, Nr. Pt. Moresby 16.iii.1965", "M.E. Bacchus. B.M. 1965-120" (BMNH). 15 males, 16 females "Papua New Guinea: Central, Myola, 1110m, i.2008, 09 12.630S 147.31.880E, Posman (PNG 177)", one male with an additional green label "DNA M.Balke 3409" (NHMW, ZSM). 7 males, 6 females "Papua New Guinea: Central, Kokoda Trek, 1390m, i.2008, [09°] 00.338S 147.44.252E, Posman (PNG 173)" (NHMW, ZSM). 1 male "Papua New Guinea: Central, 755m, 28.x.2009 S9.25.47.5 E147.32 59.1, Sagata (PNG229)" (ZSM).

Description.

Body size and form: Beetle small: TL-H 3.1-3.85 mm, TL 3.45-4.35 mm, MW 1.7-2.05 mm (holotype: TL-H 3.4 mm, TL 3.75 mm, MW 1.85 mm), with oblong-oval habitus.

Colouration: Piceous, with paler sides of pronotum and head anteriorly. Head reddish brown to dark brown, paler anteriorly. Pronotum dark brown, to piceous on disc and to reddish on sides. Elytra uniformly dark brown to piceous. Head appendages and legs proximally yellowish to reddish, legs distally darker, reddish brown ( Fig. 28 ). Teneral specimen paler, brown to reddish brown with to yellowish pronotum and head.

Surface sculpture: Shiny dorsally, with extremely fine, sparse punctation and weakly impressed microreticulation. Head with fine and sparse punctation (spaces between punctures 2-3 times size of punctures); diameter of punctures smaller than diameter of cells of microreticulation. Pronotum with much finer and sparser punctation than on head, very inconspicuous. Punctation on elytra invisible. Pronotum and elytra with weakly impressed microreticulation; head with microreticulation slightly stronger. Metaventrite, metacoxae, and abdominal ventrites distinctly microreticulate. Metacoxal plates with longitudinal strioles and weak transverse wrinkles. Punctation on venter invisible; inconspicuous on two last abdominal ventrites.

Structures: Pronotum with narrow 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 truncate.

Male: Protarsomere 4 with large, thick, strongly curved anterolateral hook-like seta. Protarsomere 5 ventrally with anterior narrow band of 26 setae and posterior row of six relatively long setae ( Fig. 32D ). Abdominal ventrites 1-3 with long strioles, abdominal ventrites 4-6 without strioles or with 1-2 small lateral strioles on each side. Median lobe with apical lobes weakly developed, not rounded, truncate in lateral view, “nose” usually indistinct ( Fig. 32A, B ). Paramere as in Fig. 32C .

Female: Without evident differences in external morphology from males, except for not modified protarsi. Abdominal ventrites 1-2 with strioles, abdominal ventrites 3-6 without strioles.

Variability.

Shape of apex of the medial lobe varies. In some specimens, especially from Myola, it is not clearly truncate in lateral view but very slightly concave and, due to that, the “nose” is more distinct.

Affinities.

Exocellina kailaki sp. nov. can be distinguished from the species of the E. danae group, E. nomax and E. pulchella sp. nov., co-occurring in the same area by its size, dorsal colouration and punctation, and shape and setation of its median lobe and paramere. For the affinities within the group, see the “Key”.

Distribution.

Papua New Guinea: Central Province ( Fig. 34 ).

Etymology.

The species is named after Kailaki Village. The name is a noun in the nominative singular standing in apposition.

Figures

Figure 34. Map of the eastern part of New Guinea showing distribution of the species of the E. jaseminae group.

Figures 26 - 29. Habitus and colouration 26 Exocelina aseki sp. nov. 27 E. jaseminae (Balke, 1998) 28 E. kailaki sp. nov. 29 E. pseudojaseminae sp. nov.

Figures 32, 33. 32 Exocelina kailaki sp. nov. 33 E. pseudojaseminae sp. 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.