Alona guttata Sars, 1862

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 : 1266

Alona guttata Sars, 1862

Vávra (1900) found this species near Stanley but gave no description of his specimens, only stating ‘‘Die mir vorliegenden Exemplare stimmen mit der genannten Art überein’’. Smith and Sayers (1971) and Brooks et al. (2005) have also recorded this species from the Falkland Islands. Smirnov (1974) lists six subspecies, two of which are known from South America, namely A. guttata tuberculata whose valves and head are covered with pits, and A. guttata guttata , which is supposedly cosmopolitan. Our specimens were of average size, 0.45 mm (slightly larger than European specimens); valves with longitudinal lines; length:height51.5; antennules do not reach tip of rostrum; ocellus in the middle between tip of rostrum and eye, smaller than the latter; dorsal margin of post-abdomen variable, more curved than European specimens from Lake Dümmer, Germany ( Hollwedel and Poltz 1985), 9–12 denticles with distally increasing length. Several of our specimens were noticeably different. They possessed a distally rounded post-abdomen and additionally bore two to three smaller denticles ( Figure 9 ). These are referred to as Alona cf. guttata .

Figures

Figure 9. Alona cf. guttata, female, post-abdomen. Scale bar: 0.5 mm.