Grouvellinus leonardodicaprioi, Freitag, Hendrik, Pangantihon, Clister V. & Njunjic, Iva, 2018

Freitag, Hendrik, Pangantihon, Clister V. & Njunjic, Iva, 2018, Three new species of Grouvellinus Champion, 1923 from Maliau Basin, Sabah, Borneo, discovered by citizen scientists during the first Taxon Expedition (Insecta, Coleoptera, Elmidae), ZooKeys 754, pp. 1-21 : 3-5

Grouvellinus leonardodicaprioi sp. n. Figures 2, 5, 6

Type locality.

Malaysia, Sabah (Eastern Borneo Island), Maliau Basin, upstream Giluk Falls, ca. 4°44'49"N, 116°52'38"E, ca. 950 m a.s.l. (Fig. 12A)

Type material.

Holotype ♂ (BOR/COL): "MALAYSIA: Sabah: Maliau Basin: \ upstr. Giluk Falls; bottom rock, run; \ ca. 4°44'49"N, 116°52'38"E, ca.950m a.s.l. \ 01.X.2017, leg. I. Njunjić, CV. Pangantihon, P. Serail (GilF3g)"; terminal parts of abdomen incl. aedeagus glued separately; right foreleg, left protarsus incl. parts of protibia and left antenna lacking; right elytral apex slightly damaged.

Etymology.

The new species is named in honour of the actor Leonardo DiCaprio to acknowledge his inspiring work in promoting environmental awareness and bringing the problems of climate change and biodiversity loss into the spotlight. The species name was selected during a naming ceremony at Maliau Basin Studies Centre on 6 October 2017, in which expedition participants as well as a large number of field centre staff and porters took part.

Description.

Body obovate, 2.97 mm long (CL), 1.60 mm wide (EW), 1.9 times as long as wide (CL/EW).

Dorsal colouration (Figs 2, 5A) black with slight metallic lustre; claws and antennae dark brown; pubescence yellow. Ventral side (Figs 5B, C) very dark brown. Plastron pubescence shiny golden.

Head 0.65 mm wide (HW); ID 0.27 mm; partly retractable; labrum with dense fringes of moderately long setae, punctures very small and dense; frons and clypeus moderately pubescent, setae moderately long, punctures small and moderately dense; intervals almost flat and glabrous. Frontoclypeal suture distinct, slightly concave. Eyes moderately protruding. Antennae genus-typical, slightly shorter than HW.

Pronotum (Fig. 5A) 0.85 mm long (PL), 1.12 mm wide (PW), distinctly wider than long (PL/MW), widest posterior 0.25, distinctly narrower than elytra, anteriorly distinctly attenuate; anterior margin convex; median carina absent, distinct sublateral carinae present posterior 0-0.3; oblique impressions very shallow; laterobasal impression very shallow, indistinct; pronotal disc moderately vaulted, densely punctate; punctures moderately big and shallowly impressed; interstices glabrous and flat; setae comparably short; pronotal impressions appearing rugose by irregularly enlarged punctures. Hypomeron rugose, increasingly pubescent (plastron) ventrad.

Prosternum (Fig. 5B) very short, lateral portions with very dense, fine pubescence (plastron); median portion and process glabrous; prosternal process distinctly parti tioned and elevated from remaining prosternum, short, distinctly wider than long, posteriorly broadly rounded; margins conspicuously fringed; sub-posteriolateral portion slightly impressed, rugose.

Scutellum (Fig. 5A) elongate sub-cordiform, posteriorly impressed, glabrous.

Elytra (Figs 2, 5A) roundly elongate, strongly convex dorsally, 2.31 mm long (EL), ca. 1.4 times as long as wide (EL/EW); apices separately conically pointed in posterior 0.05, with eight to nine (most lateral row partly divided anterior 0.3-0.7) longitudinal rows of punctures (striae); striae moderately (anterior portion) to inconspicuously (posterior portion) impressed; punctures of rows 2 and 3 dissolved beyond anterior 0.8; remaining punctures somewhat regularly arranged (except for most lateral row), but distinctly varying in size and degree of impression: much larger (2-6 times of intervals) and deeply impressed medio-basally, small (0.1-0.3 times of intervals) and shallowly impressed sub-apically; interstices glabrous; intervals 7 and 8 with finely crenulate carinae approx. from basal 0.1 to 0.9; carinate interval 8 extending as "shoulder crest" basad up to pronotal angle; intervals 1-3 slightly broadly elevated basal 0.1-0.2; at least intervals 1, 3, 5, 7, 8 with rows of scattered setae (most of them presumably broken off in the specimen examined); lateral elytral margin serrate and with row of setae.

Mesoventrite (Fig. 5C) with two pairs of moderately deeply impressed grooves, one sub-rectangular pair behind procoxae and another sub-trapezoidal pair medially behind prosternal process.

Metaventrite (Fig. 5C) disc glabrous, with longitudinal impression along median suture, medioanteriorly impressed; anterior angles (bordering mesocoxae) process-like elevated; lateral metaventrite portions with large irregular punctures or impressions; their interstices rugulose; most lateral portion (approx. between hind coxae and shoulder) with dense plastron pubescence.

Abdominal ventrites (Fig. 5C). Ventrite 1 with pair of longitudinal carinae between glabrous disc and densely pubescent lateral portions (plastron); broad lateral portions of ventrites 1-4 and almost entire ventrite 5 densely covered with plastron (Fig. 5C); median glabrous portions with sparse punctures and small setae.

Legs (Fig. 2) slightly shorter than body, hind leg longest; hind tibiae slightly broader than those of the other legs; tibia longer than tarsus and femur in all legs; parts of coxae, proximal femora and entire inner (ventral) face of tibiae and femora moderately densely covered with short adpressed setae; outer (dorsal) edge of femora and tibiae and inner (ventral) edge of tarsomeres 1-4 with fringes of long trichoid setae; remaining portions with scattered short setae; distal portion of tibiae and inner edge with longitudinal rows of robust setae; apex of tibiae additionally with pair of spines.

Aedeagus (Fig. 6 A–C) ca. 840 μm long, ca. 180 μm wide. Phallobase slightly asymmetrical basally, reaching basal 0.41 of total aedeagus length. Median lobe almost four times as long as wide, distinctly overreaching parameres, evenly slightly conical towards round apex. Ventral sac large, apically inflated beyond apex (presumably more inflated than in regular position), internal surface entirely densely covered with moderately short and thin spines, outer surface also covered with such spines up to the level of the parameres (presumably because more inflated than in regular position). Parameres distinctly shorter than median lobe, apices evenly rounded (lateral view), conical from insertion to half-length and very slender in apical half in lateral view, with approx. 20 trichoid setae in apical fourth of ventrolateral margin; most apical setae distinctly longer than all others.

Male sternite IX ('spiculum gastrale’) with posterior margin rounded and entirely fringed with a broad, distinctly sclerotized margin; paraprocts closely attached to posterior portion, sub-equally long, not reaching apical margin; median strut broken and not examined.

Female and larva.

Unknown.

Differential diagnosis.

By its unusually large size, Grouvellinus leonardodicaprioi sp. n. resembles G. hercules Jäch, 1984 from Nepal, which also shares some other characters with the new species (only 7th and 8th elytra interval crested, margins of prosternal process fringed, elytral apices pointed), but G. leonardodicaprioi , sp. n. can be distinguished by the slenderer elytra, the fully glabrous (in between punctures) and not elevated median pronotum, the shallower elytral striae, as well as by its conspicuously varying aedeagus with broad main piece which distinctly overreaches the evenly rounded paramere tips (vs. very slender main piece only slightly overreaching the conically tapered paramere tips in G. hercules ). The large size and other characters mentioned above also allow clear distinction from the species described below and any known congeners from Malaysia and Indonesia.

Distribution.

This species is only known from the type locality, the Giluk Falls of the upper Maliau Basin, Sabah (Figs 11, 12A).