Limbodessus skalei, Hendrich & Surbakti & Balke, 2020

Hendrich, Lars, Surbakti, Suriani & Balke, Michael, 2020, Limbodessus skalei sp. nov., a new diving beetle species from the west Papuan Archipelago (Coleoptera: Dytiscidae, Bidessini), Zootaxa 4763 (4), pp. 587-592 : 588

Limbodessus skalei sp. nov.

Type locality. Riverbank of Werabiai River approx. 8 km from river mouth following the water course [0.2585S ° 130.9856E °], Waigeo, Raja Ampat Province, West Papua.

Type material: Holotype: Male, “ Indonesia, W-Papua, Raja Ampat Prov ., Waigeo, Werabiai River, 197m, -0.258519° 130.985685°, 11.1.2004 ”, “ HOLOTYPE Limbodessus skalei sp.n. Hendrich & Balke det. 2019” [red printed label] ( MZB) . Paratypes: One male and one female with same data as holotype ( ZSM). Each paratype is provided with a red printed paratype label.

Measurements. Holotype: TL = 2.05 mm, TL-H = 1.85 mm, MW = 0.95 mm, TL/MW = 2.16. Paratypes, male: TL = 2.05 mm, TL-H = 1.85 mm, MW = 0.95 mm, TL/MW = 2.16; female: TL = 2.0 mm, TL-H = 1.75 mm, MW = 1.0 mm, TL/MW = 2.00.

Description. A small yellow Limbodessus , with dark markings on elytra and slight habitus disruption between pronotum and elytron. Dorsoventrally rather flattened.

Coloration: Antennae, palpi and head yellowish, pronotum completely testaceous, basally darkened between pronotal striae. Elytron testaceous with a wide basal and subbasal dark blackish-brown band ( Fig. 1 ). Ventral side including prosternal process and metacoxal plates somewhat darkened, legs and epipleura yellowish.

Sculpture and structure: Head: Punctation fine, somewhat sparse, posteriorly slightly coarser and somewhat denser. Cervical line present (faint or partly dissolved into punctures in female). Pronotum: Broadest at posterior corners. Punctation coarse, dense, almost evenly distributed, microreticulation absent. Sides of pronotum margined and almost evenly rounded. Angle between pronotum and elytra rather distinct, pronotal and elytral plicae present. Striae almost straight, ¾ length of pronotum and strongly impressed. Elytra: Striae almost straight, 1/6 length of elytra. Punctation coarse, dense, almost evenly distributed, microreticulation not visible, shiny. Ventral side: Base of elytral epipleuron without raised transverse carina delineating a basal pit. Metacoxae and metaventrite covered with numerous larger punctures, surface shiny, without microreticulation. Sexes dimorphic considering shape of antennomeres (see below).

Male: Antenna filiform. Dorsal surface with coarse punctures but otherwise with shiny surface ( Fig. 1 ). Median lobe of aedeagus as in Fig. 2a, b . Shape of penis fairly uniform, apex straight and pointed, with tiny setae on tip. Paramere with hook or bent finger like apical part ( Fig. 2c ).

Female: Antenna more or less moniliform and body slightly broader (see measurements).

Etymology. The species is named after our friend and engaged coleopterist André Skale (Gera, Germany). The specific epithet is a substantive in the genitive case.

Differential diagnosis. The new species can be easily separated from all other epigean Limbodessus by the combination of its colorful dorsal surface ( Fig. 1 ), smaller size and form of the median lobe ( Fig. 2 ) (see Watts & Leijs 2005, Balke et al. 2016).

Distribution. Known only from the type locality on Waigeo, around eight kilometers upstream Werabiai Riv- er.

Ecology. The three specimens were collected at the edge of the Werabiai River ( Fig. 3 ), among stones and pebbles, of small, exposed puddles without any vegetation.

Figures

FIGURE 1. The Limbodessus species known from New Guinea and adjacent islands. Dorsal habitus of L. skalei sp. nov., holotype, male (a); L. alexanderi (b), L. baliem (c) and L. compactus (d). Scale bar = 1 mm.

FIGURE 2. Limbodessus skalei sp. nov., median lobe of aedeagus in ventral (a), lateral view (b), paramere, lateral view (c). Scale bar = 0.25 mm.

FIGURE 3. Werabiai River and river banks approx. 8 km from river mouth, Waigeo island (Photo Dmitry Telnov, Natural History Museum, London, 20.II.2012).