A review of Thysanarthria with description of seven new species and comments on its relationship to Chaetarthria (Hydrophilidae: Chaetarthriini) Author Fikáček, Martin Department of Entomology, National Museum, Cirkusová 1740, CZ- 19100 Praha 9 – Horní Počernice, Czech Republic & Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ- 12844 Praha 2, Czech Republic mfikacek@gmail.com Author Liu, Hsing-Che Department of Environmental Engineering and Management, Chaoyang University of Technology, No. 168, Jifeng E. Rd., Taichung City 413, Taiwan td965771@gmail.com text Acta Entomologica Musei Nationalis Pragae 2019 2019-06-20 59 1 229 252 journal article 8143 10.2478/aemnp-2019-0020 a03ecce2-b526-4f94-aa65-620016956099 1804-6487 4488918 9F309FCC-A2ED-47B9-BC37-D0C4A3B482E5 Thysanarthria ceylonensis Hebauer, 2001 ( Figs 6 K–O, 11 ) Thysanarthria ceylonensis Hebauer, 2001: 396 Type material examined. HOLOTYPE : ♂ ( MZLU ), SRI LANKA : NORTHERN PROVINCE : ʻCeylon, N. Prov. / Kudattanai / 6 mls SE Point Pedro / 13.II.62, Loc. 70 // At pond in semi- / desert // Lund University / Ceylon Expedition 1962 / Brinck-Andersson- / Cederholm // MZLU / Type no. / 3120:1 // Photo 2017 / by MZLU // MZLU / 2017 / 511’. Additional material examined. INDIA : MADHYA PRADESH: 1 ♂, 2 specimens ( NHMW , NMPC ): River Denwa, ca. 8 km SSE Matkuli, Satpura Range, 400 m , 28.ii.2008 , lgt. M. Jäch, S. & P. Sharma; 1 ♀ ( NHMW ): Hoshangabad Distr., Bandrabhan, ca. 60 km SSE Bhopal, ca. 5 km NE Hoshangabad, River Narmada, 280 m , 23.‒24.ii.2008 , lgt. M. Jäch, S. & P. Sharma; 1 spec. ( NHWM ): Chhindwara Distr., Bhadhua Chora (stream), ca. 10 km E Matkuli near Mahul Jhir, 400 m , 28.ii.2008 , lgt. M. Jäch, S. & P.Sharma; 1♀ ( NHMW ): Hoshangabad Distr., Dhobighat Nala (stream), ca. 2 km SE Pachmarhi,Saphura Range, 900 m , 27.ii.2008 , lgt. M. Jäch, S. & P. Sharma. Fig. 6. Male genitalia of Thysanarthria species, holotypes (A–I, K–O) and paratype (J). A–E – T.bifida sp. nov. (A–C – whole aedeagus in dorsal, lateral and ventral view; D–E – detail of median lobe and parameres in dorsal and ventral view). F–J – T. trifida sp. nov. (F–H – whole aedeagus of the holotype in dorsal, lateral and ventral view; I – details of parameres of the holotype; J – same of the paratype). K–O – T. ceylonensis Hebauer, 2001 (K–M – whole aedeagus in dorsal, lateral and ventral view; N–O – details of median lobe and parameres in dorsal and ventral view). Redescription. Body length 1.5–1.7 mm ( holotype 1.5 mm ), maximum body width 0.9–1.0 mm ( holotype 0.9 mm ). Head and labrum black and pronotum uniformly yellowish; elytra yellowish with slightly darker lateral parts; legs reddish to yellowish. Head with strong microsculpture on interstices; punctation sparse, each puncture bearing pointed seta. Eyes separated by 3.5× the width of one eye in dorsal view. Pronotum with sparse setiferous punctation similar to that on head; interstices without microsculpture. Elytra with 10 striae sharply impressed except anteromedially (near scutellar shield) where neither striae nor serial punctures are visible; intervals weakly convex at midlength and near apex; interval punctation sparse, setiferous; interstices without microsculpture. Aedeagus ( Figs 6 K–O) 0.4 mm long. Phallobase not much wider at base of parameres than more basally, only indistinctly narrowed at midlength; arcuate in lateral view. Paremere moderately wide basally, slightly narrowing towards apex, apex widely angulate. Median lobe widely bottle-shaped, rounded apically, without paired subapical projections; apex not reaching level of parameral apices; gonopore rounded, situated far from apex. Differential diagnosis. Thysanarthria ceylonensis resembles T. bengalensis , T. brincki and H. saurahana in having strong mesh-like microsculpture on the head, but it can be easily distinguished from all these species as well as from all other Thysanarthria by a very characteristic aedeagus. Biology. Specimens from Madhya Pradesh were collected at the sides of small to large rivers with stony banks (e.g., Fig. 11D ) but precise microhabitat is not known (M. A. Jäch, pers. comm.). Distribution. Described from Sri Lanka ( HEBAUER 2001 ) but here recorded from central India ( Madhya Pradesh ), hence the species is likely widespread in the Indian Peninsula.