Pleuroxus varidentatus Frey, 1993

Smirnov, Nikolai N., Kotov, Alexey A. & Coronel, Jorge S., 2006, Partial revision of the aduncus-like species of Pleuroxus Baird, 1843 (Chydoridae, Cladocera) from the southern hemisphere with comments on subgeneric differentiation within the genus, Journal of Natural History 40 (27 - 28), pp. 1617-1639 : 1630-1631

Pleuroxus varidentatus Frey, 1993

( Figures 50–52 )

Pleuroxus varidentatus Frey 1993b, p 177 –184, Figures 132–164; Smirnov 1996, p 46 –47, Figures 151–156.

Holotype: a parthenogenetic female 0.62 mm long on a slide in glycerol jelly, deposited in the La Plata Museum, Argentina ( Frey 1993b) . Paratypes (slides): two females, ALMG GEN 951 A; two females, AM P40973 ; two females, GOS 21292a; two females, NHM 1992.31–32; two females, USNM 251694 . Paratypes (tubes): five females, ALMG GEN 951 B; five females, AM P40974 ; five females, GOS 21292b; five females, NHM 1992.33– 37; five females, USNM 251694 .

Type locality

‘‘A marshy channel alongside a small wooden church in Pta. Bandera, Santa Cruz Province, Argentina’’ ( Frey 1993b).

Material examined

Twenty-three parthenogenetic females from ‘‘Arroyo aqua caliente’’, near San Salvador de Jujuy, Departamento de Cochinoca, Jujuy Province, Argentina, collected on 1 November 1901 by E. Nordenskiöld, SMNH Cladocera 24; one parthenogenetic and one ephippial female from ‘‘La Quinta’’ (Laguna La Quinta, 140 km from San Salvador de Jujuy), Jujuy Province, Argentina, collected on 1901 by E. Nordenskiöld, SMNH Cladocera 25.

Short diagnosis

Body ( Figure 50 ) relatively light and transparent, dorsum without a medial keel, posteroventral angle with one to three, rarely four denticles. Rostrum distinctly shorter than labral keel ( Figure 51 ). Head shield with rounded posterior end, anteriorly makes a blunt rostrum, PP53.0–3.6 IP. Striation on head shield and valve ill-defined. Setae at valve ventral margin situated exactly marginally. Setules on posterior margin of valve situated on inner face of valve submarginally. Postabdomen ( Figure 52 ) long, slightly narrowing distally, with rounded and slightly prominent dorso-distal angle, its anal, preanal, and postanal portions roughly equal in length, anal teeth strong, solitary or in series of two to three in distal half of postanal margin, and as series of fine setules in its basal portion. Anntenna I with a welldefined basal peg. On antenna II, one apical seta on each branch shorter than other two setae. On limb I smallest ODL seta short, two largest IDL setae greatly unequal in size. On innerdistal portion of limb II, scrapers 1–3 with size decreasing basally; setules on gnathobase delicate, naked, filter plate II with eight setae. On exopodite III setae 1 and 3 unequal in length, filter plate III with eight setae. Filter plate IV with six setae. Exopodite V with a single projection distally to distal seta 1 (according to Frey 1993b, Figure 164).

Description

See Frey (1993b).

Distribution

Our new findings change ideas on the distributional range of this species in South America, now, in addition to Frey’s (1993b) single locality in the Province of Santa Cruz, it is found in Jujuy Province, in the northern part of the Argentinian Andes.

Figures

Figures 47–55. Different species of Pleuroxus from the southern hemisphere. (47, 48) Pleuroxus carolinae from small rockpools near Fika Patso, Republic of South Africa, postabdominal claws. (49) Pleuroxus scopuliferus from unknown water body near Morro Chico, southern Chile, lectotype. (50–52) Pleuroxus varidentatus, ephippial female from La Quinta, Argentina. (53–55) Pleuroxus hardingi sp. nov. from pools near the city of Cochabamba, Bolivia, general view, postabdomen and postero-ventral portion of valve. Scale bars: 0.01 mm (47, 48, 55); 0.1 mm (49–54).