REVISION OF SIMOCEPHALUS DAPHNIIDAE 

Fig. 6 S. vetulus. A, maxillule, B, antennule of male, C, antennule of female, D, mandibles, E, molar region of mandibles. 
populations of Simocephalus s. str. The dendrogram consists of 2 
large clusters. The first of them combines the populations 1—13 (thin 
line), and the second combines 14—16 (thick line). This means that 
the similarity within both clusters is stronger than between them. In 
other words, we can presume that populations 1-13 and 14-16 
belong to two separate species. The diagrams of characters provide 
support for this presumption (Fig. 19B,C). The areas occupied by 
populations |—13 (thin line) and by populations 14—16 (thick line) 
on the diagram only overlap to a minor extent at one point. There- 
fore, there is a morphological hiatus between these groups. 
Examination ofthe types shows that one of these species is S. vetulus 
(1-13); the other is S. mixtus (14-16). 
Similar reasoning shows that 2 species of Simocephalus s. str.: S. 
mixtus and S. vetuloides occur in Eastern Siberia (Fig. 20). There 
appear to be 3 species in Eurasia: S. vetulus in Europe, S. vetuloides 
in Eastern Siberia and S. mixtus in all regions of Asia and in Eastern 
Europe. The latter species is rather variable. 
All measured African specimens (9 series) belong to S. mixtus. I 
have also one series of S. vetulus from Morocco, but these specimens 
are in poor condition and it is impossible to measure them. 
S. vetulus (O.F. Miiller, 1776) 
Figs 3-18 
Daphne vetula O.F. Miiller, 1776: 199; Daphnia sima O.F. Miiller, 
1785: 91: Monoculus nasutus Jurine, 1820: 133; Monoculus sima: 
Jurine, 1820: 129; Simocephalus vetulus: Schédler, 1858: 18; S. 
vetulus var. angustifrons Lilljeborg, 1900: 171;S. vetulus var. brandti 
Cosmovici, 1900: 156 syn. nov. (nec Daphnia brandtii Fischer, 
1848); S. vetulus angustifrons: Behning, 1941: 181; S. vetulus 
gebhardti Ponyi, 1955: 313; S. mixtus hungaricus Ponyi, 1956: 57. 
TYPE MATERIAL. The types appear to be lost. S. vetulus is often 
confused with closely related species, so the designation of a 
neotype is necessary. Neotype (designated here): Denmark, Zea- 
land, vicinity of Copenhagen. Dyrehaven, 55°46'N, 12°34'E, 11. 5. 
1901: MPA: 9 ad. (ZMC, CRU-319). 
