Branchinecta gaini
From Wikipedia, the free encyclopedia
| Branchinecta gaini | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Branchiopoda |
| Order: | Anostraca |
| Family: | Branchinectidae |
| Genus: | Branchinecta |
| Species: | B. gaini |
| Binomial name | |
| Branchinecta gaini | |
Branchinecta gaini is a species of fairy shrimp from Antarctica and Patagonia. It is the largest freshwater invertebrate in Antarctica, at 16 mm (0.63 in) long. It lives on bacteria and other organisms, surviving the winter as resting eggs.
Branchinecta gaini is found from "half-way down the Antarctic Peninsula" northwards, including southernmost South America and subantarctic islands such as South Georgia and the South Orkney Islands.[2] It is the only fairy shrimp on mainland Antarctica, where it is "rather widespread on the Antarctic Peninsula";[3] records of "Branchinecta granulosa" from Antarctica are all misidentifications of B. gaini.[4] In the South Shetland Islands, B. gaini has been recorded from the lakes on the ice-free Byers Peninsula of Livingston Island (alongside Boeckella poppei and the benthic cladoceran Macrothrix ciliata),[5] in Lake Wujka, and in Sombre Lake on Signy Island (alongside Boeckella poppei and the carnivorous Parabroteus sarsi).[6]
The only known fossil records of the genus Branchinecta are of B. gaini; its eggs have been found in mid to late Holocene (4,200 BP)[7] lake deposits on James Ross Island, on the east side of the Antarctic Peninsula.[8] B. gaini no longer occurs on James Ross Island, presumably because the lakes are unfrozen for too short a period for B. gaini to complete its life cycle.[8] The egg cases were found to be most abundant during the Holocene climatic optimum, indicating that cyanobacterial mats must have been present in the lake then.[9] Eggs dating from 5,500 BP have also been found on Signy Island, where the species persists.[7]
Description
Branchinecta gaini can reach a total length of 16 millimetres (0.63 in), making it the largest freshwater invertebrate in Antarctica.[10] It uses its trunk limbs to scrape food from the substrate.[11]