Cyclops Kikuchii Smirnov, 1932 (Copepoda, Cyclopoida), Eine Selbständige Art Aus Süddeutschen Gewässern

Abstract

The hitherto existing subspecies Cyclops vicinus kikuchii Smirnov, 1932 was originally described by materials from Japan; later it was found in Russia, Poland, and Czechoslovakia. Compared with Cyclops vicinus Uljanin, 1875 the subspecies is characterized mainly by the short inner furcal seta (no. 1) in proportion to furcal and body length. According to Wierzbicka (1934) both types could interbreed to produce fertile offspring. Materials collected in an old reservoir, the Neuweiher near Meersburg (Lake Constance), and further in Lake Seeg and in the Schwaltenweiher (southern Bavaria), allowed morphological and morphometrical studies (fig. 1, tab. I), completed by comparative chromatin diminution and enzyme electrophoresis. The morphological studies (tab. I) confirmed the differences in length of the inner furcal seta compared with C. vicinus. The only five specimens from Lake Seeg at least indicate the probability of a seasonal variation. The course of chromatin diminution (fig. 2) appears identical in qualitative aspects for both cyclopids. In the enzyme electrophoresis remarkable differences were found in GOT (glutamate oxaloacetate transferase), APK (arginine phosphokinase) and PGM (phosphoglucomutase) (fig. 3). Together with the morphological details and the sympatric occurrence with C. vicinus in Lake Seeg and in the Schwaltenweiher, these results confirm the separate status of the species Cyclops kikuchii Smirnov, 1932. This species passes its diapause during summer in the fifth copepodid instar, while C. vicinus aestivates in the fourth instar.