

REVISION OF SIMOCEPHALUS DAPHNIIDAE 
Paralectotypes collected with lectotype: CBS: 9 9 Qad., 29 Q juv. 
(ZMO, F 9176, F 9177), Argentina: MPA: 152 Qad., 109 Qjuv., 
62 Qe.,c'(ZMO, F 18438); MPA: 272 Qad., 22 Qjuv., 32 Ge. 
(BMNH, 1901. 12. 12. 251-261). 
MATERIAL EXAMINED 
DIAGNOSIS. Measurements. @ 9 ad.: 1.0-2.0mm,2 Qe. 1.0- 
1.5mm,o"": 0.7—1.0mm. 
Female (Fig. 44). Dorso-posterior valve prominence small, sepa- 
rated from the rest part of valves by shallow embayments. Its length 
less than the diameter of circle inscribed in its contour. Denticles 
cover less than 2 of posterior and less than 1/3 of dorsal margin. No 
denticles on ventral margin. Ocellus short. Frons with denticles. 
Morphology of trunk limbs unstudied, because it was impossible to 
dissect the type material. 
(Fig. 43). Lectotype, paralectotypes. 
DISTRIBUTION. (Fig. 43) Argentina, Brasil (Sao Paulo). 
REMARKS. Daday (1905) believes S. semiserratus and S. capensis 
to be one species. Kanduru (1981) and Michael & Sharma (1988) 
sink S. semiserratus into the synonymy of S. serrulatus. Sars (1901) 
writes: ‘I am enabled to state with full certainty its [S. semiserratus] 
distinctness from the European species [S. serrulatus]. In addition to 
its somewhat larger size, it is easily distinguished by the far less 
prominent posterior projection of the carapace, and somewhat dif- 
ferent shape of the head. The marginal denticles, moreover, which in 
S. serrulatus extend throughout the whole length of the hind margin, 




> 
@ S. latirostris © S$. heilongjiangensis 
49 
are in this species always limited to their uppermost part only’. It 1s 
my belief that S. semiserratus is a separate species. First, statistical 
analysis shows that it is separated from S. serrulatus in two pairs of 
independent metric characters (Orlova-Bienkowskaja, 1995a). Sec- 
ond, it differs from it in the marginal denticles of the valves. Third, 
it occurs in South America sympatrically with S. serrulatus and 
cannot be a geographical subspecies of this species. 
S. mirabilis sp.nov. 
Figs 45; 46 
ETYMOLOGY. The name ‘Mirabilis’ means ‘Surprising’. 
TYPE MATERIAL. Holotype: U.S.A., Alabama, Mobil Co., lower part 
of Langan Park lake, 24. 5. 1987, leg. Fitzpatrik: MPA: 9 ad. (BMNH 
1997. 1709). Paratypes: collected with holotype: MPA: 11 9 Qad., 
92 Qjuv. (BMNH 1997. 1710-1719); U.S.A., Oklahoma, Tulsa, 
Oxley Nature Center, Mallard lake, 36°10'N, 98°W, 12. 6. 1991, leg. 
Berner: MPA: 109 Qad., 29 Qjuv. (AC); Argentina, Rio Parana, 
Catay pond, leg. Frutos: MPA: 49 Qad., 72 Qjuv. (AC). 
MATERIAL EXAMINED. (Fig. 43) Holotype, paratypes. 
DIAGNOSIS. Measurements. 9 9 ad. 1.0—1.2mm. 
Female (Figs 45; 46). Dorso-posterior valve prominence moderate, 
separated from the rest part of valves by moderate embayments. Its 
length less than the diameter of circle inscribed in its contour. 
Denticles cover less than 2 of posterior and less than 1/3 of dorsal 
CEOS 
oul 
O S. lusaticus 
@S. lusaticus & gs. heilongjiangensis 
Fig. 51 Locations where the species of S. (Aquipiculus) were collected for this study or reported in literature. 
