Laccobius (Glyptolaccobius) silvester, Gentili, 2006

Gentili, Elio, 2006, Revisional notes on the genus Laccobius. I. Subgenus Glyptolaccobius (Coleoptera: Hydrophilidae), Acta Entomologica Musei Nationalis Pragae 46, pp. 57-76 : 72-74

Laccobius (Glyptolaccobius) silvester sp. nov.

( Figs. 34-35 )

Type locality. India, Uttar Anchal, W Loharket Village, 30 km N Bageshwar, 1800-1900 m a.s.l.

Type material. HOLOTYPE: 1 J, 2.2 × 1.2 mm ( NHMW): ‘ INDIA: Uttaranchal / 30 km N Bageshwar / W Loharket [village] // 1800-1900 m. / 24.VI.2003; leg. Z. / Kejval & M. Tryzna’.

Description. Small-sized species (holotype 2.2 mm long and 1.2 mm wide). Body oval, moderately convex, its outline not interrupted between pronotum and elytra; elytra not explanate.

Head. Labrum of males without specula; trapezoidal in dorsal view, with straight anterior and posterior margins and feebly oblique sides, shiny black. Clypeus moderately convex, not deflexed towards margins, shiny black, with sparse and faint punctures, without distinct ‘systematic punctures’. Eyes oblique, weakly convex, not protruding, separated by slightly more than two times width of one eye, nearly reniform in lateral view, emarginate posteriorly. Maxillary palpi less than 0.5 times as long as head wide; palpomere 2 not swollen, narrower and nearly as long as palpomere 3; palpomere 4 1.5 times as long as palpomere 3, outer margin nearly straight, inner margin rounded, with truncate apex. Mentum ca 0.5 times as wide as long, almost flat, at least in centre, covered with faint punctures. Eight antennomeres; scape (antennomere 1) longer than three following antennomeres together; pedicel (antennomere 2) cone-shaped; two intermediate antennomeres (3-4) very short; cupule (antennomere 5) asymmetrical, oval in ventral view, crescent-shaped and emarginate in dorsal view; club with segments 1 and 3 nearly equal in length, segment 1 more stout, segment 2 shorter and narrower.

Thorax. Pronotum without distinct ‘systematic punctures’ but covered with sparse and faint punctation; smooth and shining; black in centre and along anterior and posterior margins, yellow coloration of lateral margins widening posteriorly. Prosternum well developed, tectiform medially and with fine, clearly traced median carina. Scutellum black, equilateral. Mesoventrite reaching anterior mesothoracic margin at single point, rather flat except for median carina, the latter more raised anteriorly and forming small acute tooth slightly anterior of middle coxae. Metaventrite with rather weakly raised middle portion, the latter slightly projecting anteriorly between middle coxae, with hydrofuge pubescence except for posteromedian glabrous area on raised middle portion. Anepisternum 3 ca 4.5 times as long as wide, subparallel. Elytra with complete parasutural furrow and ca 20 longitudinal series of punctures: ten primary rows of well discernible setigerous punctures, and ten alternate, scarcely visible rows; lateral margins neither serrate nor denticulate; epipleura oblique, pseudepipleura nearly vertical and separated by distinct ridge consisting of small arcs; their anterior dilated portion ending before hind coxae.

Legs. Fore coxae almost contiguous, fore trochanters pubescent; middle coxae separated by median carina of mesoventrite; tip of hind trochanters free, not abutted to hind femora. Femora with distinct tibial grooves distally on inner faces; basal third of ventral side of fore femora covered with hydrofuge pubescence; middle and hind femora nearly glabrous. Tibiae relatively short and stout, progressively wider towards apices, spiny (ventral face with three longitudinal rows of stiff setae, apices with two long spurs), without swimming hairs; hind tibiae curved inwards. Fore tarsomeres 2 and 3 expanded in males. Middle and hind tarsi with fine and sparse swimming hairs on dorsal face; hind tarsomere 1 much shorter than tarsomere 2. Claws of moderate size, robust, weakly curved.

Abdomen. Six distinct ventrites, ventrites 1-5 rather shiny and sparsely pubescent, ventrite 6 more dull, densely pubescent and somewhat retractable; ventrite 1 not carinate; posterior margin of ventrite 5 subtruncate.

Male genitalia. Median lobe slender, straight, excised at apex; parameres nearly as long as median lobe and slightly longer than phallobase ( Figs. 34-35 ).

Differential diagnosis. Laccobius silvester sp. nov. pertains to the group of Glyptolaccobius species with curved hind tibiae and elytra with longitudinal rows of punctures. Within the group it differs from L. celsus and L. munus by the lack of sulciform punctural rows, from L. sharmai by the lack of yellowish dots and stripes near the elytral base and suture, and from L. shorti sp. nov. by the parameres nearly as long as phallobase.

Etymology. The mountain zones of Uttar Anchal are rich of luxuriant forests.

Distribution. India (Uttar Anchal).

Figures

Figs. 30-38. 30-31 – Laccobius senguptai Gentili, 1979, holotype. 30 – aedeagus, dorsal view; 31 – ditto, lateral view. 32-33 – L. sharmai Gentili, 1995, holotype. 32 – aedeagus, dorsal view; 33 – ditto, lateral view. 34-35 – L. silvester sp. nov., holotype. 34 – aedeagus, dorsal view; 35 – ditto, lateral view. 36-38 – L. shorti sp. nov. 36 – holotype, aedeagus, dorsal view; 37 – paratype from Chiang Mai, aedeagus, lateral view; 38 – holotype, ventral view.