Daphnia pulex Leydig, 1860

Dartnall, Herbert J. G. & Hollwedel, Werner, 2007, A limnological reconnaissance of the Falkland Islands; with particular reference to the waterfleas (Arthropoda: Anomopoda), Journal of Natural History 41 (21 - 24), pp. 1259-1300 : 1271-1272

Daphnia pulex Leydig, 1860

Although Ekman (1905) emphasized the similarities between the specimens he found on the Falkland Islands with Daphnia obtusa from Tierra del Fuego by Vávra (1900), our specimens are definitely D. pulex , not D. obtusa .

Female: 1.42–1.65 mm, valves broad and oval, dorsal and ventral margin with denticles, inner ventral margin without setae, shell spine short or absent, all juveniles with spines; ventral margin of head concave; antennulae do not reach tip of rostrum. Post-abdominal claw with a pecten of eight to nine denticles.

Juvenile male: 0.62–0.95 mm; anterior ventral margin with long spines; rostrum short; antennulae nearly as long as flagellum, not on a curved projection. Second abdominal projection relatively short, not reaching the root of abdominal setae; dorsal margin of postabdomen straight as in D. obtusa . Daphnia pulex was reported from the Falkland Islands by both Smith and Sayers (1971) and Brooks et al. (2005). According to Benzie (2005) the occurrence of D. pulex in South America is doubtful, suggesting our specimens may belong to a different species. This needs clarification.