Grouvellinus andrekuipersi, 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 : 9-15

Grouvellinus andrekuipersi sp. n. Figures 4, 9, 10

Type locality.

Malaysia, Sabah (on 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. Paratypes: 2♂, 2♀ (BOR/COL) same data as holotype; 5♂, 3♀ (BOR/COL) "MALAYSIA: Sabah: Maliau Basin: \ Creek E Nepenthes Camp; bottom rock, \ run; ca. 4°43'57"N, 116°52'45"E, ca. 1000m a.s.l. \ 01.X.2017, leg. I. Njunjić, P. Serail, C. de Groot (NepC3g)"; 1♂, 1♀ (BOR/COL) "MALAYSIA: Sabah: Maliau Basin: Creek W Nepenthes Camp; bottom rock, run; ca. 4°44'04"N, 116°52'41"E, 1000 m a.s.l.; 01.X.2017, leg. I. Njunjić & H. Freitag (NepC4g)"; 2 ♂, 2 ♀ (BOR/COL) "MALAYSIA: Sabah: Maliau Basin: \ Giluk River; Cryptochorinae water plants, \ run; ca. 4°44'36"N, 116°52'21"E, ca. 980m a.s. \ l.01.X.2017, leg. I. Njunjić, H. Freitag, L. Seip, P. Piccoli (GilR2r)"; 7♂, 7♀, 7exs. (NMW) "Malaysia, Sabah, Crocker \ Range, Rafflesia Centre, \ around km 61 of road Kota \ Kinabalu, Tambunan, \ 13-14.VI. 1996, 6 a"; 1♂ (NMW) "Malaysia, Sabah, ca. 7 km S \ Sapulut, Saupi riv. in primary \ forest, ca. 500m a.s.l.,J.F. Kočiam lgt."; 1♂, 4♀, (NMW) "Malaysia, Sabah, Crocker, \ Range, Sunsuron, 10.-11.VI. \ 1996, 8a, Sunsuron riv. flowing \ through deforested area"; 1♂, 1 ex. (NMW) "MAL., Sarawak 1993 \ Kelabit HL, Umg. Bario \ 26.2., ca 1000 m \ leg. M. Jäch (14)"; 1♂, 1 ♀, 1 ex. (NMW) "MAL., Sarawak 1993 \ Kelabit HL, 6km E Bario \ Pa Ukat, 27.2., ca 1000 m \ leg. M. Jäch (16)"; 1♂, 2exs. (SP) "MALAYSIA: Sabah: Tawau, Lucia River, 750 m a.s.l.".

Etymology.

The new species is named after the Dutch astronaut André Kuipers in recognition of his engagement against the loss of the planet’s natural resources and his ambassadorship for various entomological organizations. The name was elected in an online public contest organized by the science program De Kennis van Nu of the Dutch public broadcaster NTR.

Description.

Body elongate obovate, 1.7-1.8 mm long (CL), 0.86-0.91 mm wide (EW), 2.0 times as long as wide (CL/EW).

Dorsal colouration (Fig. 4) predominantly dark brown; pronotum black; elytra darkest at disc; basal area between shoulder and sutural interval usually with a pair of more or less distinct and extended yellowish brown spot; commonly also sub-apical elytral areas with indistinct faint paler spots; legs dark brown increasingly paler distad; tarsi and antennae golden brown; maxillary and labial palps brown; pubescence shiny yellowish. Ventral side (Fig. 9B, C) reddish dark brown.

Head 0.35-0.39 mm wide (HW); ID 0.16-0.17 mm; partly retractable; frons, clypeus, and anterior and lateral areas of labrum moderately pubescent; punctures small; intervals medially flat and glabrous, laterally rugulose. Frontoclypeal suture straight, indistinct. Eyes slightly protruding. Antennae genus-typical, usually semi-circularly folded around anterio-lateral eye margin.

Pronotum (Fig. 9A) 0.52-0.55 mm long (PL), 0.62-0.64 mm wide (PW), wider than long (PL/MW), widest posterior 0-0.3, distinctly narrower than elytra, anteriorly attenuate; anterior margin slightly convex; median carina absent, but with a pair of short posterior-median rugose patches (anterior of the scutellum); sublateral carinae very indistinct and short; oblique impression moderately deep, narrow, extending approx. anterior 0.3-0.75; laterobasal impression shallow and indistinct; pronotal disc slightly vaulted; entire pronotum moderately sparsely punctate; punctures very small and shallowly impressed; setae moderately long; interstices glabrous and flat; laterobasal impression and lateral margins rugulose. Hypomeron rugose, moderately densely pubescent.

Prosternum (Fig. 9B) short; lateral portions with very dense, fine pubescence (plastron); median portion including process medially broadly impressed, rugulose except for glabrous median portion; prosternal process sub-quadrate, approx. as wide as long; lateral margins finely striate.

Scutellum sub-triangular, medially slightly impressed, glabrous.

Elytra (Fig. 4) roundly elongate, moderately convex dorsally, 1.29-1.33 mm long (EL), ca. 1.5 times as long as wide (EL/EW), widest at the middle, slightly tapered anteriad; apices separately rounded, with eight longitudinal, slightly impressed rows of punctures; punctures much larger (in row 1: approx. as wide as intervals) and deeper impressed basally, increasingly smaller (in rows 1-4: 0.2 times of intervals) and more shallowly impressed apically, regularly arranged in median rows only, less regularly arranged in lateral rows; interstices glabrous; only interval 8 with (genus-typical) serrate carina; all carinae with row of yellowish pubescence; lateral elytral margin serrate.

Mesoventrite (Fig. 9C) with two pairs of deep sub-trapezoidal grooves, one behind procoxae, another medially, the latter more distinct in males.

Metaventrite (Fig. 9C) with large glabrous disc; longitudinal impression along median suture limited to posterior half; lateral portions with irregular impressions and irregularly micro-striate interstices; posterior-lateral portions with very dense, fine pubescence (plastron).

Abdominal ventrites (Fig. 9C). Ventrite 1 with pair of longitudinal carinae between glabrous disc and densely finely pubescent lateral portions (plastron); broad lateral portions of ventrites 1-2 and almost entire ventrites 4-5 (Fig. 9B) densely covered with plastron and scattered, moderately long setae; the latter more dense at apex and lateral margins of ventrite 5.

Legs (Fig. 4) approx. as long as body; hind leg longest; tibia longer than tarsus and femur in all legs; outer (dorsal) edge of all femora and tibiae with longitudinal row of robust trichoid setae (in both sexes); coxae and inner (ventral) faces of femora and tibiae densely covered with plastron-like short adpressed setae; inner (ventral) edge of distal tibia and tarsomeres 1-4 with fringe of long trichoid setae and short spine-like setae; apex of tibiae with pair of apical spines and a cluster of long spine-like setae (most conspicuous at hind tibia). Legs not conspicuously varying between sexes.

Aedeagus (Fig. 10A, B) ca. 440 μm long, ca. 100 μm wide. Base reaching basal 0.46 of total aedeagus length. Median lobe ca. four times as long as wide, distinctly overreaching parameres, slightly conical towards round apex in apical third. Ventral sac apically inflated, internally densely stippled and with dense sub-median fringes of moderately long, thin spines. Parameres apically conical (in both, ventral and lateral view), very slender in apical 2/3 in lateral view, usually with more than 20 trichoid setae in apical third, most of them at outer ventral face; most apical 2-4 setae longest and inserted at dorsal face.

Male sternite IX as in previous new species.

Ovipositor (Fig. 10C) similar to that of Grouvellinus quest sp. n., but overall slightly shorter (total length ca. 580 μm); stylus slightly shorter (30 μm long), and more bent outwards; coxite relatively longer (260 μm long), apically more broadened, ca. 2.8 times long as proximal portion; valvifer 330 μm long.

Larva.

Unknown.

Differential diagnosis.

Grouvellinus andrekuipersi sp. n. is similar in size, pronotal and elytral surface structure to G. thienemanni Jäch, 1984 and G. sumatrensis Jäch, 1984, but displays a slenderer pronotum in relation to the elytra and slightly convex lateral elytral margins (vs. slightly concave or straight in basal half in G. thienemanni and G. sumatrensis ). The yellowish elytral patterns commonly seen in G. andrekuipersi sp. n. were not observed in any examined specimen (n = 20) of the two congeners. Their entire elytra and pronotum appear overall slightly paler (brown). Additionally, the pronotal basis is entirely rugulose ( “shagreened”) in G. thienemanni and G. sumatrensis (vs. glabrous with a pair of median rugose patches in G. andrekuipersi sp. n.). In G. thienemanni , the pronotal disc is additionally more densely punctate. The aedeagus of the new species is also similar in size and proportions to that of G. thienemanni , but in G. andrekuipersi sp. n., the paramere tips are distinctly conical (vs. evenly rounded in G. thienemanni ) and the median lobe is wider and conically tapering towards apex (vs. evenly slender in apical 1/5 in G. thienemanni ). From the previous new species ( G. quest sp. n.), G. andrekuipersi sp. n. can easily be distinguished by 1) the pale elytral patches; 2) the smoother elytral surface due to the lack of any other elytral carinae than at interval 8; 3) the relatively broader and laterally convex elytra; 4) the sparse punctures of the pronotum; and 5) the smaller aedeagus with distinctly varying base, median lobe, and parameres.

Distribution.

This species is known only from Borneo Island, namely the upper Maliau Basin, Tawau Hills Park, and Crocker Range in Sabah and two sites in eastern Sarawak (Fig. 11).