Exocelina tekadu Shaverdo & Balke

Shaverdo, Helena, Sagata, Katayo & Balke, Michael, 2016, Taxonomic revision of New Guinea diving beetles of the Exocelinadanae group, with the description of ten new species (Coleoptera, Dytiscidae, Copelatinae), ZooKeys 619, pp. 45-102 : 49

Taxon classification Animalia Coleoptera Dytiscidae

3. Exocelina tekadu Shaverdo & Balke sp. n. Figs 4, 26

Type locality.

Papua New Guinea: Morobe Province, Tekadu, ca. 07°38'19.4"S; 146°32'12.4"E, 400-500 m a.s.l.

Type material.Holotype: male "PAPUA N.G.: Morobe Prov., Lakekamu Bas., Tekadu 28.2.1998, 400-500 m leg. Riedel" (NHMW).

Diagnosis.

Beetle medium-sized; brown, with reddish head and pronotum; shiny; male antennomeres modified: antennomere 2 distinctly enlarged, antennomeres 3-6 stout; protarsomere 4 with large, thick, strongly curved anterolateral hook-like seta; median lobe with slightly curved, broad apex in lateral view and with concave apex in ventral view, on both lateral sides with small bunch of fine distal setae; paramere without notch on dorsal side. The species is similar to Exocelina miriae and Exocelina rufa in the presence of the enlarged male antennomere 2, but differs from them in the shape and setation of the median lobe, as well as in distinctly finer dorsal punctation and microreticulation; from Exocelina rufa also in size and coloration.

Description.

Size and shape: Beetle medium-sized (TL-H 3.95 mm, TL 4.5 mm, MW 2.2 mm), with oblong-oval habitus, broadest at elytral middle. Coloration: Head reddish brown, with small darker areas posterior to eyes; pronotum reddish brown, with small brown to dark brown area on disc; elytra dark brown, with narrow reddish sutural lines; head appendages yellowish red, legs reddish, distally darker, especially metathoracic legs (Fig. 26).

Surface sculpture: Head with rather dense punctation (spaces between punctures 1-2 times size of punctures), evidently finer and sparser anteriorly; diameter of punctures smaller than diameter of cells of microreticulation or equal for some punctures. Pronotum with much sparser and finer punctation than on head. Elytra with very sparse and fine punctation. Pronotum and elytra with weakly impressed microreticulation, dorsal surface shiny. Head with microreticulation stronger. Metaventrite and metacoxa distinctly microreticulate, metacoxal plates with longitudinal strioles and transverse wrinkles. Abdominal ventrites with distinct microreticulation, strioles, and very fine sparse punctation.

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 narrow, slightly convex, with distinct lateral bead and few setae; neck and blade of prosternal process evenly jointed. Abdominal ventrite 6 slightly truncate.

Male: Antennomere 2 distinctly enlarged, antennomeres 3-6 stout (Fig. 26). Protarsomere 4 with large, thick, strongly curved anterolateral hook-like seta. Protarsomere 5 ventrally with anterior band of more than 50 and posterior row of 7 rather long setae (Fig. 4A). Median lobe with slightly curved, broad apex in lateral view and with concave apex in ventral view, on both lateral sides with small number of fine setae situated in a bunch on distal part of median lobe close to apex. Paramere without notch, slightly concave on dorsal side and with dense setae on subdistal part; proximal setae inconspicuous (Fig. 4 B–D). Abdominal ventrite 6 with 7-8 lateral striae on each side.

Female: unknown.

Distribution.

Papua New Guinea: Morobe Province. The species is known only from the type locality (Fig. 40).

Etymology.

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