Thysanarthria wadicola, Fikáček & Liu, 2019

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 : 248-250

Thysanarthria wadicola sp. nov.

( Figs 10 F–J, 11 )

Thysanarthria sulcata (misidentification): HEBAUER (1997: 267; records from Oman, illustration of genitalia); HEBAUER (2001:399, taxonomic revision).

Thysanarthria cf. sulcata (part): FIKÁČEK et al. (2010: 139; misidentification).

Thysanarthria sp. (SLE127): SHORT & FIKÁČEK (2013; molecular phylogeny).

Thysanarthria wadicola: RIBERA et al. (2019: 264 ; review of Oman aquatic beetles).

Type material. HOLOTYPE: ♂ ( NMPC): OMAN: Wadi Andam, 20 km N Samad, 650 m, 17.–18.iv.1985, lgt. C. Holzschuh. PARATYPES: 2 ♂♂ ( SMNS): same data as the holotype; 3 spec. ( IBEB): Murri env., wadi Bani Ghafir, 759 m, stream with pools, 23º29′46.2″N 56º53′34.8″E, 7.iv.2010, Ribera & Cieslak lgt.; 1 spec. ( IBEB): Said Bin Sahran env., wadi Indam, Rd. 33, 463 m, residual pools, 22º45′15.2″N 58º00′56.9″E, 8.iv.2010, Ribera & Cieslak lgt.

Additional material examined. UNITED ARAB EMIRATES: 1 ♀ ( NMPC): Hatta, at light, 8.–26.iv.2006, lgt, A. van Harten. This female specimen was collected very close to the type locality of the species and externally corresponds well with the Oman specimen, we hence consider it conspecific. As no male is available from the locality, We are however not including it into the type series.

Redescription. Body length 1.6–1.7 mm (holotype 1.6 mm), maximum body width 0.9–1.0 mm (holotype 0.9 mm). Head and labrum black; pronotum uniformly dark brown; elytra uniformly dark brown; legs brown. Head without microsculpture on interstices; punctation sparse, each puncture bearing pointed seta. Eyes separated by 3.3× 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 (around 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 10 F–J) 0.4 mm long. Phallobase slightly widened at bases of parameres, slightly narrower than parameres combined, weakly narrowing more basally in ventral/dorsal view, in lateral view phallobase c. as long as parameres, arcuate, and strongly constricted subbasally. Parameres wide basally, continually narrowing into prolonged pointed apex, outer face slightly sinuate, in lateral view very wide basally and very narrow apically. Median lobe very short, less than half the length of parameres, without distinct membranous part on the apex, without paired projections, gonopore circular, situated apically.

Differential diagnosis. Thysanarthria wadicola differs from most species of the genus except T. persica in uniformly dark brown pronotum and elytra. For differences from T. persica see under that species.

Etymology. The species name is a combination of wadi (an Arabic word for seasonally dried-up riverbed) and the suffix -cola derived from the word incola (Latin, = inhabitant). Noun in apposition.

Biology. Part of the specimens was collected at margins of small rocky pools at the side of a drying-up stream (see RIBERA et al. 2019: Figs 7–8 ).

Distribution. The species is so far known only from few closely situated localities on the northeastern tip of the Arabian Peninsula.

Figures

Fig. 10. Male genitalia of Thysanarthria species, holotypes.A–E – T. persica sp. nov. (A–C – aedeagus in dorsal, lateral and ventral view; D–E – detail of median lobe and parameres in dorsal and ventral view). F–J – T. wadicola sp. nov. (F–H – aedeagus in dorsal, lateral and ventral view; I–J – detail 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.

Fig. 7. Male genitalia of Thysanarthria championi (Knisch, 1924).A–E – lectotype of Chaetarthria championi Knisch, 1924 (A–C – whole aedeagus in dorsal, lateral and ventral view; D – detail of median lobe and parameres in dorsal view; E – same after KOH treatment, with fully everted internal sac). F–J – lectotype of Chaetarthriomorphus sulcatus Chiesa, 1967 (F–H – whole aedeagus in dorsal, lateral and ventral view; I–J – details of parameres and median lobe in dorsal and ventral view).

Fig. 8. Male genitalia of Thysanarthria species, holotypes.A–E – T. chui 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. hongsonensis Hebauer, 2001 (F–H – whole aedeagus in dorsal, lateral and ventral view; I–J – details of parameres and median lobe in dorsal and ventral view). K–O – T. madurensis 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).