Exocelina mianminensis 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

17. Exocelina mianminensis Shaverdo & Balke sp. nov. Figs 38 , 43

Exocelina undescribed sp. MB0688: 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: Sandaun Province, Mianmin, 04°52.86'S, 141°31.71'E, 700 m a.s.l.

Type material.

Holotype: male "Papua New Guinea: Sandaun, Mianmin (pool), 700m, 21.x.2008, 04.52.858S 141.31.706E, Ibalim (PNG 198), "DNA M.Balke 3749" [green] (ZSM). Paratypes: 16 males, 8 females with the same label as the holotype, one male with an additional green label "DNA M.Balke 3758" (NHMW, ZSM). 2 males, 3 females "Papua New Guinea: Sandaun, Mianmin (pool), 700m, 21.x.2008, 04.52.858S 141.31.706E, Ibalim (PNG 197) (ZSM). 1 male "Papua New Guinea: Sandaun, Mianmin (pool), 990m, 23.x.2008, 4.54.570S 141.35.490E, Ibalim (PNG 193) (ZSM). 4 males "Papua New Guinea: Sandaun, May River, 970m, 19.x.2003, 4.49.779S 141.38.174E, K. Sagata (WB43)", one of them with an additional green label "DNA MB688" (ZSM).

Description.

Body size and form: Beetle medium-sized: TL-H 3.75-4.25 mm, TL 4.15-4.6 mm, MW 1.95-2.3 mm (holotype: TL-H 3.75 mm, TL 4.15 mm, MW 1.95 mm), with oblong habitus.

Colouration: Piceuos. Head piceous, with reddish brown anterior margin. Pronotum dark brown to piceous, with reddish brown to brown sides. Elytra uniformly piceous. Head appendages and legs proximally yellowish, legs distally darker, reddish brown ( Fig. 38 ). Teneral specimen paler.

Surface sculpture: Submatt dorsally, with dense and coarse punctation and weakly impressed microreticulation. Head with very dense and coarse punctation (no spaces between punctures or spaces 1-2 times size of punctures); diameter of punctures equal to diameter of cells of microreticulation. Pronotum with distinct punctation, finer than on head. Punctation on elytra distinct, finer and sparser than on head. Elytra with weakly impressed microreticulation; head and pronotum with microreticulation stronger than on elytra. Metaventrite, metacoxae, and abdominal ventrites distinctly microreticulate. Metacoxal plates with longitudinal strioles and weak transverse wrinkles; abdominal ventrites 2-4 with few strioles, two last one without strioles but with very weak wrinkles. Punctation on venter fine but distinct.

Structures: Pronotum with narrow lateral bead. Base of prosternum and neck of prosternal process with distinct ridge, rounded anteriorly. Blade of prosternal process lanceolate, narrow, slightly convex, with distinct bead and few setae laterally. Abdominal ventrite 6 truncate or very slightly concave.

Male: Protarsomere 4 with large, thick, strongly curved anterolateral hook-like seta. Protarsomere 5 ventrally with anterior band of ca. 60 and posterior row of 17 relatively long setae ( Fig. 43D ). Abdominal ventrite 6 without lateral striae on each side, except one with setae. Median lobe slender, lateral sides slightly thickened; in lateral view, apex short, pointed, and curved downwards; in ventral view, lateral sides evenly expanded subdistally and apex slightly concave ( Fig. 43A, B ). Paramere with distinct dorsal notch and subdistal part well developed, with long and dense subdistal and inconspicuous proximal setae ( Fig. 43C ).

Female: Without evident differences in external morphology from males, except for not modified protarsi.

Affinities.

In the area of its distribution, E. mianminensis co-occurs with species of the E. ekari , E. okbapensis , E. broschii , E. casuarina and E. danae groups. From species of the E. ekari group, the species differs in larger size, presence of the pronotal bead, evidently stronger dorsal punctation, and the shape of the median lobe. From the other species, E. mianminensis sp. nov. can be distinguished by body size, form, and colouration, dorsal punctation, simple male antenna, and shape and setation of its median lobe and paramere. In the general appearance, the new species is more similar to E. ibalimi Shaverdo et al., 2018, but can be easily distinguished from it in presence of the pronotal bead. Male abdominal ventrite 6 without lateral striae was so far known only for E. sima Shaverdo et al., 2018 among New Guinea Exocelina . For affinities within the group, see the “Key”.

Distribution.

Papua New Guinea: Sandaun Province ( Fig. 45 ).

Etymology.

The species is named after Mianmin Village. The name is an adjective in the nominative singular.

Figures

Figure 45. Map of the eastern part of New Guinea showing distribution of the species of the E. larsoni and takime groups.

Figures 35 - 39. Habitus and colouration 35 Exocelina larsoni (Balke, 1998) 36 E. nomax (J. Balfour-Browne, 1939) A holotype B specimen from Tapini 37 E. warahulenensis sp. nov. 38 E. mianminensis sp. nov. 39 E. takime (Balke, 1998).

Figures 43, 44. 43 Exocelina mianminensis sp. nov. 44 E. takime (Balke, 1998) 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.