Laccobius (Cyclolaccobius) motuoensis, Jia, Fenglong, Chen, Jia-Hui & Fikacek, Martin, 2019

Jia, Fenglong, Chen, Jia-Hui & Fikacek, Martin, 2019, A new species of Laccobius Erichson, 1837 (Hydrophilidae, Coleoptera) from the Chinese Himalaya, with comments on taxonomic status of subgenera Glyptolaccobius Gentili, 1989 and Cyclolaccobius Gentili, 1991 and additional faunistic records from China, ZooKeys 889, pp. 65-80 : 65

Laccobius (Cyclolaccobius) motuoensis sp. nov. Figs 1-6 , 7-16 , 17-22 , 23-25

Type locality.

China, Xizang, Linzhi Prefecture, Motuo County, Lagong, 29°18'50"N, 95°19'07"E.

Type material.

Holotype: ♂ (SYSU): China, Xizang, Linzhi Prefecture, Motuo County, Lagong (中国, 西藏, 林芝, 墨脱县, 拉贡), 29°18'50"N, 95°19'07"E, 1271 m. 22.vi. 2018, Shi-shuai Wang & Zu-long Liang let. (transcribed from Chinese). Paratypes (47 spec.): 39 spec. (SYSU, NMPC): same label data as the holotype; 8 spec. (SYSU): China, Xizang: near road of Motuo to Bomi, Wudang waterfall, 18.viii.2018, Run Zhou.

Diagnosis.

Length 1.9-2.2 mm. Dorsal surface dark brown or black with broad lateral yellow band on pronotum and elytra, posterior half of elytra yellowish. Head and pronotum without shagreen on interstices. Head without pale preocular spots. Antenna with seven antennomeres, the third antennomere very small, globular. Elytra often with a pair of yellow spots on the base of third primary series of punctures. Elytra without sulci, with 10 primary series of punctures; primary series of punctures strong and coarse, secondary ones consisting of smaller and more scarcely arranged punctures, punctures with short yellow setae. Aedeagus: total length 0.45 mm; median lobe as long as parameres, broad basally, narrowest medially, subapically with a series of backward directed setae; parameres subrectangular apically, almost as wide as medial lobe at apex.

Description.

Total length 1.9-2.2 mm (holotype: 2.15 mm); maximum width 1.35-1.45 mm (holotype: 1.4 mm). Total length / total width ratio = 1.5. Body oval, moderately convex, maximum width at anterior third of elytra ( Fig. 1 ).

Head. Black with greenish reflection, without preocular spots, smooth. Labrum about 2.7 × as wide as long, without specula in both sexes, feebly emarginated on anterior margin, surface densely punctured ( Fig. 7 ). Clypeus and frons blackish, surface with irregularly arranged punctures, punctures sparse and less impressed than on labrum, each puncture with decumbent white seta on disc, punctures in anterior corner of clypeus as dense as on labrum. Frontoclypeal suture scarcely apparent. Eyes oblong, oblique ( Fig. 8 ), closest to each other posteriorly, slightly protruding laterally, minimum interocular distance in dorsal view 2.7 × the width of one eye. Mentum with mesh-like microsculpture anteriorly and laterally ( Fig. 7 ), without punctures, but smooth and with a few punctures in posterior half; submentum smooth with sparse punctures. Maxillary palpi ( Fig. 14 ) yellowish, not becoming dark at extreme apex; palpomere 2 almost same length as palpomere 3, palpomere 4 asymmetrical, inner margin straight and outer margin convex, ca. 1.5 × as long as palpomere 3. Apical labial palpomere asymmetrical with straight inner face and convex outer face ( Fig. 7 ), about as long as penultimate one. Antennae with 7 antennomeres ( Fig. 9 ), yellow brown with antennal club of the same color; scape ca. 2.2 × as long as pedicel, antennomere 3 very small, globular, cupule globular and asymmetrical; antennomeres 5-7 with densely arranged setae, antennomere 7 constricted near apex.

Thorax. Pronotum transverse, smooth; black with greenish reflection, lateral margins with yellow stripe that extends to posterior margin near posterior corner ( Figs 1 , 2 ), the yellow patch with posterior margin 2 × as wide as anterior margin; punctures coarse and sparse, bearing decumbent yellowish setae; lateral stria fine, ending in posterior corner, but shortly continuous along anterior margin. Scutellar shield equilaterally triangular, black with few punctures. Prosternum black with dense decumbent pubescence, with a longitudinal keel medially ( Fig. 10 ). Mesoventrite with arrow-head-shaped elevation ( Fig. 10 ), the top of the elevation with a tuft of long setae; a longitudinal carina reaching to posterior margin of mesocoxae ( Fig. 10 ). Metaventrite pubescent with a very narrow longitudinal glabrous area medioposteriorly ( Fig. 10 ). Elytra smooth, slightly elongate, ca. 1.1 × as long as wide, dark brown with wide lateral yellow margin that always narrower than posterior margin of pronotal lateral yellow margin ( Figs 1 , 4 ); posterior half yellow, fused with lateral yellow margin ( Figs 1 , 2 ); base of elytra with a pair of distinct pale yellow spots ca. at mid width ( Figs 1 , 3 ), sometimes elytra almost black on disc, and the basal yellow spot absent or unclear ( Fig. 4 ); primary series punctures not sulciform; primary series of punctures strong and coarse, regularly arranged; secondary ones with small and scarce punctures ( Fig. 11 ). Epipleura oblique, ending at level of metafemora.

Legs. Yellow brown. Trochanters pubescent; profemora with anterior surface densely pubescent basally, with tibial grooves; protibiae smooth, bearing stiff setae ( Fig. 14 ). Mesotrochanters and mesofemora smooth ( Fig. 13 ), the latter with tibial grooves; mesotibiae with longitudinal rows of stiff setae ( Fig. 13 ). Metatrochanters and metafemora smooth ( Fig. 13 ), the latter with tibial grooves; metatibiae with longitudinal rows of stiff setae, long spur as long as first and second tarsomeres combined ( Fig. 16 ). Tarsal natatory setae nearly absent. Legs with five tarsomeres; second metatarsomere ca. 1.4 × as long as metatarsomere 3 ( Fig. 16 ).

Abdomen. Ventrites 1-5 smooth, without microsculpture, sparsely pubescent; each ventrite with long setae posteriorly, ventrite 6 densely pubescent ( Fig. 12 ).

Male. Second protarsomere dilated, with a clasping structure that contains 7 lobes ( Fig. 15 ).

Aedeagus. ( Figs 5 , 6 ). Total length 0.42 mm. parameres nearly 1.6 × as long as phallobase. Phallobase 1.3 × as long as wide. Median lobe as long as parameres, broad basally, gradually narrowed from base to mid length and then slightly widened to apex; with a series of backward directed setae subapically, apex rounded. Parameres subrectangular apically, almost as wide as medial lobe apically.

Differential diagnosis.

This species closely resembles L. yunnanensis Gentili, 2003 and L. sipeki Gentili & Fikáček, 2009 in the genital morphology (including the series of long hairs on distal half of the median lobe) and the coloration of elytra having a dark base with small basal spots and widely pale apical portion. It can be distinguished from L. yunnanensis by having an elytral series regular throughout (somewhat irregular at base in L. yunnanensis ), primary series of punctures distinctly stronger and coarser than secondary ones (with some punctures at least as large as those on primary series in L. yunnanensis ) and the median lobe ca. the same width in apical half (distinctly widened apically in L. yunnanensis ). It can be distinguished from L. sipeki by the absence of the parasutural furrow (with distinct rather deep parasutural groove in L. sipeki ) and the apex of the median lobe reaching the level of parameral apices only (slightly overlapping parameral apices in L. sipeki ).

Etymology.

This species is named after type locality.

Distribution.

Only known from two close localities in the eastern Himalaya (Xizang, Motuo County).

Figures

Figures 1 - 6. Laccobius (Glyptolaccobius) motuoensis sp. nov. 1, 2 habitus (1 dorsal view 2 lateral view) 3, 4 base of the elytron (3 specimen with yellow spot 4 specimen without yellow spot) 5, 6 male genitalia (5 dorsal view 6 lateral view).

Figures 7 - 16. Laccobius (Glyptolaccobius) motuoensis sp. nov. 7 head, ventral view 8 compound eye in lateral view 9 antenna 10 ventral view of thorax 11 punctures on elytral base 12 abdomen 13 mesothoracic leg 14 prothoracic leg 15 male protarsus 16 metathoracic leg.

Figures 17 - 22. Male genitalia of the species similar to Laccobius motuoensis sp. nov. 17 - 19 L. sipeki Gentili & Fikacek, holotype (17 ventral 18 lateral 19 ventral) 20 - 22 L. yunnanensis Gentili, specimen from China: Yunnan: Rehai Hot springs (coll. NMPC) 20 detail of the apical half of medial lobe 21 ventral view 22 lateral view.

Figures 23 - 25. Habitats of Laccobius motuoensis sp. nov. Xizang: near road of Motuo to Bomi, Wudang waterfall.