Graptodytes SEIDLITZ , 1887

Fery, Hans & Bouzid, Slimane, 2016, Notes on Graptodytes SEIDLITZ, 1887, re-instatement of G. laeticulus (SHARP, 1882) as valid species and description of Tassilodytes nov. gen. from Algeria (Coleoptera, Dytiscidae, Hydroporinae, Siettitiina), Linzer biologische Beiträge 48 (1), pp. 451-481 : 453

The genus Graptodytes SEIDLITZ, 1887

SEIDLITZ (1887: 59) introduced the subgenus Graptodytes as one of three subgenera of the genus Hydroporus CLAIRVILLE, 1806 . His subgenus comprised all species with sublateral longitudinal impression on each side of the pronotum, except those of the genus Oreodytes SEIDLITZ, 1887 . He divided the subgenus into three species groups: the first one comprising those species which are treated today in the genus Stictonectes BRINCK, 1943 , the second group comprising species which are now in Rhithrodytes BAMEUL, 1989 , and the third group comprising those which are treated today in Graptodytes . ZIMMERMANN (1919: 147) raised Graptodytes to generic rank and included, additionally to the species of SEIDLITZ' s first two groups, Siettitia balsetensis ABEILLE DE PERRIN, 1904 , Metaporus meridionalis ( AUBÉ, 1838) , and those species which are treated today in the genus Porhydrus GUIGNOT, 1945 (the latter two genera were introduced by GUIGNOT 1945).

Today the genus Graptodytes is included in the subtribe Siettitiina SMRŽ, 1982 of the tribe Hydroporini AUBÉ, 1836 . Originally, SMRŽ introduced the tribe Siettitiini "... to include multiple unrelated Hydroporinae ..." (MILLER & BERGSTEN 2014: 144). These originally included genera are given in SMRŽ (1981). This classification was afterwards either overlooked, not accepted or refused ( ÁDÁM 1996: 23). MILLER & BERGSTEN (2014: 144) gave SMRŽ' s tribe a new status – the subtribe Siettitiina SMRŽ, 1982 (in the tribe Hydroporini ). The type genus of this subtribe is Siettitia ABEILLE DE PERRIN, 1904 . In this subtribe they included Graptodytes SEIDLITZ, 1887 , Metaporus GUIGNOT, 1945 , Porhydrus GUIGNOT, 1945 , Rhithrodytes BAMEUL, 1989 , Stictonectes BRINCK, 1943 , and several subterranean genera, e.g. Siettitia . For more information on this subtribe see MILLER & BERGSTEN (2014) and PEDERZANI (1995: 64; under tribe Siettitiini SMRŽ ).

Graptodytes species are characterised by the pronotal striae relatively short and reaching neither the anterior nor the posterior pronotal margins; members of this genus have the apex of the median lobe in lateral view more or less straight and in many of them asymmetric in ventral view. Species of Porhydrus and Metaporus can be separated from Graptodytes by the lack of the sublateral pronotal striae, and species of Stictonectes (which possess also the sublateral pronotal striae) can be separated from Graptodytes by their stellate punctation (cf. figs 2A and 4A-C in BILTON 2012) of large parts of the dorsal and ventral surfaces (present also in Porhydrus ). Species of the genus Rhithrodytes can be easily distinguished from all other epigean members of the subtribe by the long sublateral stria stretched from the anterior to the posterior margin of the pronotum and by the symmetric and distinctly curved apex of the median lobe. Additionally, in contrast to all other members of Hydroporini , species of Rhithrodytes have the elytral epipleuron provided with a distinct oblique carina near the shoulder (see fig. 1 in FERY 2013) – similar to the epipleural carina e.g. in members of Hygrotini PORTEVIN, 1929 .