Laccobius (Glyptolaccobius) yinziweii, Zhang & Jia, 2017

Zhang, Ruijuan & Jia, Fenglong, 2017, A new species of Laccobius Erichson and additional faunistic records of the genus from China, with a key to subgenus Glyptolaccobius Gentili (Coleoptera: Hydrophilidae), Zootaxa 4344 (2), pp. 395-400 : 396-398

Laccobius (Glyptolaccobius) yinziweii sp. nov.

Type locality. China, Yunnan, Lushui County, Yaojiaping., 26.01˚N, 98.7˚E. China, Yunnan, Yingjiang County, Nabang, 24.57˚ N, 97.56˚ E.

Type material. Holotype: ♂ ( SYSU): China, Yunnan Province, Lushui County, Yaojiaping. 26.01˚N, 98.7˚E, 2424m. 17.V. 2016, Yudan Tang & Ruijuan Zhang lgt. (with Chinese and English labels) . Paratypes (7): 1 male, 5 females ( NMPC? MSNV? SYSU): same date as the holotype (with Chinese and English labels) ; 1 female ( SYSU): China, Yunnan Province, Yingjiang County, Nabang Town, 24.75˚N, 97.56˚E, 27.V. 2016, 239m, Yudan Tang & Ruijuan Zhang lgt. (with Chinese and English labels).

Diagnosis. Length 1.8–2.1 mm. Black, head without pale preocular spots. Seven antennomeres, the third antennomere very small, globular. Pronotal margin with wide yellow band, posterior margin with short yellow band that connects with lateral band. Elytron with yellowish lateral margin and apex that is narrow in male but wide in female, each elytron with one or two yellow or yellowish white spots basally. Elytra with irregular punctures, each puncture with a white seta, parasutural stria reaching to anterior third. Aedeagus: parameres nearly 1.4× as long as phallobase, median lobe gradually narrowed from base to apex, emarginate apically. Parameres obtusely rounded apically, slightly wider than median lobe on anterior third.

Description. Total length 1.8–2.1 mm (holotype: 2.0 mm); maximum width 1.0– 1.2 mm (holotype: 1.2 mm). Total length / total width ratio =1.7. Body oval, moderately convex, maximum width in anterior third of elytra.

Head. Black, without preocular spots. Labrum about 2.7× as wide as long, without specula in both sexes, feebly emarginated on anterior margin, surface densely punctured posteriorly. Clypeus and frons blackish, surface with irregularly arranged punctures, punctures slightly impressed but larger than labral punctures, each puncture with decumbent white seta. Frontoclypeal suture scarcely apparent. Eyes oblong, oblique, closest to each other posteriorly, slightly protruding laterally, minimum interocular distance in dorsal view 2.5× of width of one eye. Mentum slightly rugose with fine punctures, submentum smooth with sparse punctures. Maxillary palpi ( Fig. 8 ) yellowish, dark at extreme apex; palpomere 1 short; palpomeres 2 and 3 nearly equal in length and inflated at apex, palpomere 4 asymmetrical, inner margin straight and outer margin convex. Antennae with 7 antennomeres ( Fig. 8, 9 ), yellow brown with darker club; scape ca. 2.5x as long as pedicel, the third antennomere very small, globular, cupule long and asymmetrical; antennomeres 5–7 with thick setae, antennomere 7 constricted near apex.

Thorax. Pronotum transverse; black, lateral margins with yellow stripe that extends to posterior margin near posterior corner ( Fig. 4, 5 ); punctures coarse and dense, bearing decumbent whitish setae. Scutellar shield equilaterally triangular, black with few punctures. Prosternum black with dense decumbent pubescence, with a longitudinal keel medially. Mesoventrite with longitudinal anteriorly arrow-shaped keel ( Fig. 10 ). Metaventrite pubescent with a longitudinal glabrous sulcus medioposteriorly. Elytra black and slightly elongate, ca. 1.1× as long as wide, lateral margin with a sinuate irregular yellowish band widening posteriorly in female ( Fig. 5 ), while in male with a thin yellow band ( Fig. 4 ), at the base of elytra with two or four distinct pale yellow spots ( Fig. 1, 2 ); elytra with irregular punctures and all punctures with whitish setae arranged in slightly regular rows posteriorly. Parasutural furrow reaching anterior third of elytral length, very conspicuous on posterior elytral third ( Fig. 1 ). Epipleura ending at level of metafemora.

Legs. Coxae dark brown, trochanters and other segments of legs yellowish brown. Trochanters pubescent; profemora with anterior surface closely pubescent on basal half but glabrous posterior surface, with tibial grooves; protibiae smooth, each bearing stiff setae. Mesotrochanters and mesofemora smooth, the latter with tibial grooves; mesotibiae with longitudinal rows of stiff setae. Metatrochanters and metafemora smooth, the latter with tibial grooves; metatibiae with longitudinal rows of stiff setae. Tarsal natatory setae nearly absent. All tarsi with with five tarsomeres; second tarsomere as long as third and fourth combined.

Abdomen. Ventrites 1–4 smooth, without microsculpture, sparsely pubescent; posterior part of ventrites 5 and 6 densely pubescent.

Aedeagus. ( Fig. 6, 7 ). Total length 0.5 mm. parameres nearly 1.4× as long as phallobase. Phallobase 1.3× as long as wide. Median lobe shorter than parameres, gradually narrowed from base to apex, emarginate apically. Parameres slightly divergent, obtusely rounded apically, slightly wider than median lobe on basal third.

Differential Diagnosis. This species can easily be distinguished from other species by its antennae possessing only 7 antennomeres. It may be close to L. jaechi Gentili, 1988 and L. pluvialis Gentili, 2006 , but can be distinguished from them by its seven antennomeres, the third antennomere very small, globular; parasutural furrow reaching to anterior third, aedeagus with parameres subparallel, with broad apex in dorsal view and lateral view. Based on the aedeagus, the new species is close to L. munus Gentili, 1995 , but may be very easily distinguished from the latter by elytra without regular series of punctures, elytra without yellow stripes and each puncture with a white seta (striae glabrous in L. munus ). It can be easily distinguished from L. qinlingensis Jia, Gentili & Fikáček, 2013 , the sole species of Glyptolaccobius known from China by its smaller size (2.7–2.9 mm in L. qinlingensis ), each puncture on pronotum and elytra with a seta, elytra with lateral yellow margin, with large yellow portion apically and with white basal spots, parameres slightly wider than median lobe on anterior third and median lobe without spines laterally.

Etymology. This species is named after Mr. Zi-wei Yin, a specialist on Pselaphinae , Staphylinidae in Shanghai Normal University.

Figures

FIGURES 1 – 10. Laccobius (Glyptolaccobius) yinziweii sp. nov. 1 – 5: general habitus (1. dorsal view, male; 2. dorsal view, female; 3. ventral view; 4. lateral view, male; 5. lateral view, female). 6 – 7: aedeagus (6. dorsal view; 7. lateral view). 8: labial, maxillary palpi and antennae. 9: antennae. 10: mesoventrite