Exocelina lembena Shaverdo & Balke

Shaverdo, Helena, Sagata, Katayo, Panjaitan, Rawati, Menufandu, Herlina & Balke, Michael, 2014, Description of 23 new species of the Exocelinaekari-group from New Guinea, with a key to all representatives of the species group (Coleoptera, Dytiscidae, Copelatinae), ZooKeys 468, pp. 1-83 : 13-15

Taxon classification Animalia Coleoptera Dytiscidae

9. Exocelina lembena Shaverdo & Balke sp. n. Figs 26, 51

Exocelina undescribed sp. MB4922: Toussaint et al. 2014: Supplementary figs 1-4, Tab. 2.

Type locality.

Papua New Guinea: East Sepik Province, Lembena, 04°57.33'S; 143°57.30'E.

Type material.

Holotype: male "Papua New Guinea: East Sepik, Lembena, 297m, 8.ix.2009, 04 57.329S 143 57.297E, Ibalim & Pius (PNG247)" (ZSM). Paratypes: 10 males, 9 females with the same label as the holotype, two males additionally with labels "DNA M. Balke 4922", "DNA M. Balke 4923" (NHMW, ZSM). 1 male "Papua New Guinea: East Sepik, Lembena, 335m, 10.ix.2009, 04 56.859S 143 59.375E, Ibalim & Pius (PNG250)", "DNA M. Balke 4919" (ZSM). 1 male "Papua New Guinea: East Sepik, Lembena, 335m, 10.ix.2009, 04 56.859S 143 57.379E, Ibalim & Pius (PNG251)" (ZSM). 1 male, 1 female "Papua New Guinea: East Sepik, Lembena, 335m, 10.ix.2009, 04 56.921S 143 57.478E, Ibalim & Pius (PNG252)" (ZSM). 1 female "Papua New Guinea: East Sepik, Lembena, 117m, 8.ix.2009, 04 57.513S 143 57.296E, Ibalim & Pius (PNG248)" (ZSM).

Diagnosis.

Beetle small, dark brown to piceous, with paler head or only its anterior part and pronotal sides, shiny; pronotum without lateral bead or with weak traces of lateral bead; male antennomeres simple; male protarsomere 4 with large, thick, evidently curved anterolateral hook-like seta; median lobe with strong submedian constriction in ventral view and almost truncate apex in lateral view; paramere with strong notch on dorsal side and subdistal part elongate but broad, with numerous long, dense, thick, flattened setae, some of them curved at apex; setae of proximal part evident, long. The species is very similar to Exocelina brahminensis Shaverdo, Hendrich & Balke, 2012, from which differs with shape of the median lobe apex and, especially, with setation of the subdistal part of the paramere: it has only thick, flattened setae. From Exocelina mantembu Shaverdo, Hendrich & Balke, 2012, it differs with shape of the median lobe and stronger notch on dorsal side of the paramere.

Description.

Size and shape: Beetle small (TL-H 2.95-3.45 mm, TL 3.3-4.5 mm, MW 1.6-1.9 mm), with oblong-oval habitus, broadest at elytral middle. Coloration: Head dark brown to piceous, paler anteriorly; pronotum dark brown to piceous, with red to reddish brown sides; elytra uniformly dark brown to piceous; head appendages red to reddish brown, legs darker, especially metathoracic legs (Fig. 51).

Surface sculpture: Head with dense (spaces between punctures 1-3 times size of punctures) but fine punctation; diameter of punctures evidently smaller than diameter of cells of microreticulation. Pronotum with much sparser and finer punctation than on head. Elytra with extremely sparse and fine punctation, almost invisible. Pronotum and elytra with weakly impressed microreticulation, dorsal surface shiny. Head with microreticulation stronger. Metaventrite and metacoxa distinctly microreticulate, metacoxal figs with longitudinal strioles and transverse wrinkles. Abdominal ventrites with distinct microreticulation, strioles, and fine sparse punctation, coarser and denser on two last abdominal ventrites.

Structures: Pronotum without lateral bead or with weak traces of lateral bead. Base of prosternum and neck of prosternal process with distinct ridge, smooth and rounded anteriorly, with small anterolateral extensions. Blade of prosternal process lanceolate, relatively narrow, slightly convex, with distinct lateral bead and few setae; neck and blade of prosternal process evenly jointed. Abdominal ventrite 6 broadly rounded apically.

Male: Antenna simple (Fig. 26A). Protarsomere 4 with large, thick, evidently curved anterolateral hook-like seta. Protarsomere 5 ventrally with anterior row of 11 and posterior row of 4 short setae (Fig. 26B). Abdominal ventrite 6 with 6-8 lateral striae on each side. Median lobe with strong submedian constriction in ventral view and almost truncate apex in lateral view (Fig. 26C, D). Paramere with strong notch on dorsal side and subdistal part elongate but broad, with numerous long, dense, thick, somewhat flattened setae, some of them curved at apex; setae of proximal part evident, long (Fig. 26E).

Holotype: TL-H 3.45 mm, TL 3.8 mm, MW 1.85 mm.

Female: Without evident differences in external morphology from males, except for abdominal ventrite 6 without striae.

Distribution.

Papua New Guinea: East Sepik Province. This species is known only from localities near Lembena (Fig. 53).

Etymology.

The name refers to the village of Lembena where this species was collected. The name is a noun in the nominative singular standing in apposition.