Exocelina may Shaverdo & Balke

Shaverdo, Helena, Sumoked, Bob & Balke, Michael, 2017, Descriptions of two new species and one new subspecies from the Exocelinaokbapensis-group, and notes on the E. aipo-group (Coleoptera, Dytiscidae, Copelatinae), ZooKeys 715, pp. 17-37 : 26-27

2. Exocelina may Shaverdo & Balke sp. n. Figs 4, 7

Exocelina undescribed sp. MB0662: Toussaint et al. 2014: Supplementary figs 1-4, tab. 2.

Exocelina undescribed sp. MB0671: Toussaint et al. 2014: Supplementary figs 1-4, tab. 2.

Type locality.

Papua New Guinea: Sandaun Province, May River, 04°49.80'S; 141°38.17'E, above 2000 m a.s.l.

Type material.

Holotype: male "M. Balke 662", "Papua New Guinea: Sandaun, May River (WB47), 15.x.2003, K. Sagata, M. Balke: MB 662" (ZSM). Paratypes: 1 male, 2 females "Papua New Guinea: Sandaun, May River, 8.x.2003, 2627m, 4 49.779S 141 38.174E K. Sagata (WB47)", male with an additional label "M. Balke 663" (ZSM). 1 male "M. Balke 664", "Papua New Guinea: Sandaun: Sandaun, May River (WB47), 15.x.2003, K. Sagata, M. Balke: MB 664" (ZSM).

Additional material.

1 male "M. Balke 671", "Papua New Guinea: Sandaun, Mekil (WB106), 14.x.2003, K. Sagata, M. Balke: MB 671" (ZSM). 1 male "M. Balke 679", "Papua New Guinea: Sandaun, Mekil (WB106), 14.x.2003, K. Sagata, M, Balke: MB 679" (ZSM).

Diagnosis.

Beetle medium-sized; piceous, with brown head and sides of pronotum; submatt, with distinct punctation and microreticulation; male antennae simple; male protarsomere 4 with small (smaller than more laterally situated large seta), weakly curved anterolateral “hook-like” seta; male protarsomere 5 long and narrow, without concavity, with anterior and posterior rows of relatively short setae; median lobe curved, with apex curved downwards and slightly rounded in lateral view. The species is similar to the submatt representatives of the E. aipo -group with non-modified antennae but differs from them in non-modified male protarsomere 5. From E. okbapensis sp. n., it differs in the small and weakly curved anterolateral “hook-like” seta of the male protarsomere 4.

Description.

Size and shape: Beetle medium-sized (TL-H 3.6-4.65 mm, TL 3.75-5.1 mm, MW 1.9-2.4 mm), with oblong-oval habitus, broadest at elytral middle. Coloration: Head, pronotum and elytra dark brown to piceous, pronotal sides sometimes reddish brown; head appendages and legs reddish brown, distally darker (Fig. 4).

Surface sculpture: Head with relatively dense and coarse punctation (spaces between punctures 1-2 times size of punctures); diameter of punctures equal to diameter of cells of microreticulation. Pronotum with finer, sparser punctation, and more evenly distributed punctation than on head. Elytra with sparser punctation than on pronotum. Pronotum and elytra with distinct microreticulation, dorsal surface submatt. Head with microreticulation slightly stronger. Metaventrite, metacoxa, and abdominal ventrites distinctly microreticulate. Metacoxal plates with longitudinal strioles and transverse wrinkles; abdominal ventrites with strioles. Ventrum with inconspicuous punctation, more evident on metacoxal plates and two last abdominal ventrites.

Structures: Pronotum with distinct 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 and smooth, with distinct lateral bead and few lateral setae; neck and blade of prosternal process evenly joined. Abdominal ventrite 6 broadly rounded.

Male: Antennae simple (Fig. 4). Protarsomere 4 with small (smaller than more laterally situated large seta), weakly curved anterolateral “hook-like” seta. Protarsomere 5 long and narrow, without concavity, ventrally with anterior row of 14-22 and posterior row of 4-9 relatively short setae (Fig. 7D). Median lobe curved, with apex curved downwards and slightly rounded in lateral view. Paramere with distinct notch on its dorsal side and small, evidently separated subdistal part with a tuft of very dense, strong setae; proximal setae inconspicuous (Fig. 7 A–C). Abdominal ventrite 6 with 4-9 lateral striae on each side.

Holotype: TL-H 4.25 mm, TL 4.7 mm, MW 2.15 mm.

Female: Without evident differences in external morphology from males, except for non-modified pro- and mesotarsi and abdominal ventrite 6 without striae.

Variability.

Two males from Mekil have dorsal punctation finer and microreticulation less strongly impressed, therefore, they are shinier. Shape and setation of the genitals are very similar to those of the May specimens but also difficult to estimate precisely since both beetles are teneral. For these reasons, they are considered to belong to the species but are not included into the type series.

Distribution.

Papua New Guinea: Sandaun Province. The species is known from two localities in the southern part of the province (Fig. 12).

Etymology.

The species is named after May River. The name is a noun in the nominative singular standing in apposition.