REVISION OF SIMOCEPHALUS DAPHNIIDAE 
Monoculus exspinosus De Geer, 1778: 457; Daphnia exspinosa: 
Koch, 1841: 35; Daphnia sima: Lievin, 1848; Baird, 1850: 95; 
Simocephalus exspinosus Schédler, 1858: 20; Lilljeborg, 1900: 177; 
Daphnia australiensis Dana, 1852: 1271; Sars, 1888: 15; S. 
exspinosus australiensis: Dumont, 1983: 104; S. sibiricus Sars, 
1898: 329 syn. nov. ; S. productus Sars, 1903: 173; S. himalayensis 
Chiang & Chen, 1974: 129 syn. nov.; S. vamani Rane, 1985b: 225. 
TYPE MATERIAL. The types appear to be lost. There are no speci- 
mens of this species in the collection of De Geer deposited in the 
Museum of Natural History in Stockholm (L. Sandberg, curator of 
Crustacea, personal communication). The type locality is not indi- 
cated in the original description (De Geer, 1778). 
MATERIAL EXAMINED. Type material of junior synonyms: S. sibiricus 
Sars, 1898: Lectotype (designated here): Russia, Siberia, 
Verkhoyansk, 1885: MPA: 9 ad. (ZICC, 4691). Paralectotypes col- 
lected with lectotype: 99 Qad. (ZICC, 4691). S. productus Sars, 
1903: Lectotype (designated here): Kazakhstan, Akmolinsk region: 
MPA: @ ad. (ZICC, 7098). Paralectotypes collected with lectotype: 
35 2 Qad. (ZICC, N7098). Other specimens: more than 1000 speci- 
mens (2 Qad., 9 Qjuv., 9 Qe,c'o’) from 56 localities in Russia, 
Ukraine, Georgia, Kazakhstan, Uzbekistan, Tadjikistan, Mongolia, 
23 
China, India, Pakistan, Bangladesh, Egypt, Algeria, Rwanda, South 
Africa and Australia. Material is deposited in AC, ZICW, ZICC, 
MCA, SAM, AM. Some specimens are selected from the samples 
from ZIPD. 
DIAGNOSIS. Measurements. 9 9 ad.: 1.8-3.5mm., 9 Qe.: 1.2 
1.9mm,o'o": 1.0-1.3. 
Female. (Fig. 28). 12-22 anal teeth. Prominence of dorso-posterior 
valve angle small or absent. Basal pecten of postabdominal claw of 
8—12 spines of moderate size. 
DISTRIBUTION. This species is assumed to be cosmopolitan by 
many authors, but its range needs to be redefined. It occurs with 
certainty in Europe, Asia, Africa, Australia (Fig. 32). The available 
specimens from different continents belong to one morphological 
species. Unfortunately, I have no specimens from America. 
REMARKS. The original description of S. exspinosus is very short: 
‘Monoculus exspinosus branchiis dichotomis cauda simplici inflexa 
testa postice rotundata non spinosa’ (De Geer, 1778). This is appro- 
priate for any species of Simocephalus. Koch and Schdédler are often 
erroneously thought to be the authors of the species, because Koch 
(1841) described and drew it and Schédler (1858) was the first to 

Fig. 23S. mixtus, type series A, parthenogenetic female, lectotype, B, ventral part of the head of paralectotype. 
