Thysanarthria ceylonensis Hebauer, 2001

Fikáček, Martin & Liu, Hsing-Che, 2019, A review of Thysanarthria with description of seven new species and comments on its relationship to Chaetarthria (Hydrophilidae: Chaetarthriini), Acta Entomologica Musei Nationalis Pragae 59 (1), pp. 229-252 : 240-242

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.

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.

Figures

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).

Fig. 11. Distribution of Thysanarthria and American Chaetarthria in Asia (A–B) and Near East (C), and examples of habitats of Thysanarthria (D–F). Localities: D – India, Madhya Pradesh, Bhadhua Chora stream ca. 10 km E of Matkuli Jhir, habitat of T. ceylonensis Hebauer, 2001; E – Republic of South Africa, Western Cape, 8 km NEE of Stanford, habitat of T. atriceps (Régimber, 1903), collecting spot marked by an arrow; F–G – Taiwan, Wufeng distr., 4.3 km SEE of Chaoyang University of Technology, habitat of T. chui sp. nov. (G – detail of sandy shore with one alive beetle). Photo D by M. Jäch, photo E by M. Fikáček, F–G by H.-C. Liu.