Shield Shrimp/Tadpole Shrimp
I kept some of these crustaceans about 15 years ago! I am talking about the oldest surviving crustacean in the word with fossils found dating over 350 "million" years ago, 150 million years before the dinosaurs roamed the earth.
ANY IDEA YET?
Ok more clues, They belong to the class called "Branchiopods" Order " Notostraca" Family "Triopsidae" No I am not swearing at you!
More clue's There are two genera, of these strange little shrimp world wide, Triops and lepidurus both genra are considered living fossils, having not changed significantly in outward form since before the Triassic period.
Both genera are represented in Australia by a single species each, T. Australiensis and L.Apus Virdis Common names :- "Tadpole Shrimp /or Shield Shrimp".!!
The most prominent and easily recognizable feature is the dorsal carapace or shield which covers the majority of the animal.There are a pair of fixed eyes at the front of the shield and two small antennae . The body of the shrimp is long and segmented and carries up to 70 sets of small flattened legs. The last segment on the abdomen has two tails The size of both species in Australia range between 2 to 9 cm. With their broad carapace and long slender abdomen gives them an overall shape of a tadpole ,from which the name Tadpole Shrimp derives.
Triop Australiensis is only found in the north of Australia, both species can be found on the South east parts of the country with an overlap into north Victoria and L. apus virdis is found in the southern parts of the country. The two species can be easily distinguished with T. Australiensis having a smaller rounder carapace and a longer abdomen with L. Apus Virdus has a longer narrower carapace and a shorter thicker abdomen and an anal plate between the tails not found in the triops. However both species share the common names of tadpole shrimp or shield shrimp.
These little animals have a very short life span in the wild, it is estimated that they will live for about 10 to 14 days, or until their water source has dried up. In captivity they can live from 30 to 90 days depending on water conditions and temperature. In the Northern parts of Australia these strange little crustaceans literally explode out of the ground after heavy rains which create temporary pools and ponds for the shrimp to live in.
These little shrimp require male and female shrimp to mate. The female carries her eggs in a modified sack under her body the eggs are retained for a short period only after fertilization before being "laid" some larvae will develop directly without passing through metamorphosis while others will go into a period of suspended animation and will remain in this state berried under the mud on the bottom of a dried up pool until the next heavy rains, when they will hatch directly into fully formed tadpole shrimp.
These shrimp can be kept in captivity and a fairly easy to care for. All you need is a small aquarium or plastic viewing tank that will hold a minimum of three litres of pure water. They need a steady water temperature between 22-29 deg c they don't need a filter or an air pump. They do need " pure" Water, that is water that has been purified for human consumption ( not tap water) or RO water They will eat almost anything smaller than themselves but they are mainly filter feeders feeding on small microscopic animals in the sediment , they sometimes catch small water animals and can be seen grazing on some water plants Even cannibalism of recently molted fellows has been noted.
information sources :- Queensland Museum ,billabongbugs, Notostraca- Wikipedia .