Rhithrodytes BAMEUL , 1989

Fery, Hans, 2016, Notes on Rhithrodytes BAMEUL, 1989, with the description of R. minimus nov. sp. from Algeria (Coleoptera, Dytiscidae. Hydroporini, Siettitiina), Linzer biologische Beiträge 48 (1), pp. 431-450 : 432

The genus Rhithrodytes BAMEUL, 1989

The generic name Rhithrodytes was introduced by BAMEUL (1989) for a group of species which before were treated as members of genus Graptodytes SEIDLITZ, 1887 . BAMEUL (1989) established the separation of the new genus based on the distinct sublateral striae of the pronotum which extend from the anterior to the posterior margin and on the symmetric and distinctly curved apex of the median lobe of aedeagus. The declivity of the prosternum between its anterior margin and the procoxae is very weak. In contrast to all other members of Siettitiina SMRŽ, 1982 , species of Rhithrodytes have the elytral epipleuron provided with a distinct oblique carina near the shoulder (see Fig. 5 , arrow "a") – similar to the epipleural carina e.g. in members of Hygrotini PORTEVIN, 1929. This observation was reported in FERY (2013) (cf. Figs 6 and 7 for R. bimaculatus and Hygrotus impressopunctatus (SCHALLER, 1783) , respectively, which are reproductions from FERY 2013). For information about the subtribe Siettitiina see MILLER & BERGSTEN (2014) and FERY & BOUZID (2016: 451-481).

Figures

Figs 4-5: Ventral surface of Rhithrodytes minimus nov.sp.: (4) head; (5) part of metathorax and abdomen (significance of arrows explained in text).

Figs 6-7: Part of ventral surface showing epipleural carina of: (6) Rhithrodytes bimaculatus; (7) Hygrotus impressopunctatus (reproductions from FERY 2013).