Branchiopoda: Notostraca

Taxa on This Page

1. Notostraca

This content on this page copied verbatum from Encyclopedia of Earth - Crustacea under Creative Commons Attribution Share-Alike license. It is intended at some point to add additional material on evolution, paleontology, etc MAK120517

Notostraca

Introduction

Tadpole shrimp are large branchiopod crustaceans that occur in arctic Canada and on the prairies.

Morphology

(Source: Biodiversity Institute of Ontario)

Tadpole shrimp have a large, flattened carapace that covers their head and thorax. The rest of their body is elongate terminating in a pair of filamentous cercopods. Adults are from 10 to 58 mm long and have 35 to 70 pairs of thoracic legs that are often partially hidden by the carapace. The first pair of legs is used for swimming, while the rest are used for walking, digging and handling food as well as swimming.

Reproduction

Most notostracans have separate males and females (gonochoristic), but self-fertilizing hermaphrodites are not uncommon. Females have a specialized brood pouch on their eleventh pair of legs which carries their eggs. The eggs are carried in the brood pouch until they hatch into either nauplius or metanauplius larvae. These larvae undergo around 12 moults before becoming mature in 2 to 3 weeks. Adults moult throughout their life.

Ecology

Most species of notostracans occur in very temporary ponds, though one species Lepidurus arcticus is also found in large arctic lakes. Within Canada, notostracans occur in the north and the west. Notostracans feed on detritus and on anostracans, conchostracans and other benthic invertebrates.

Because of their resemblance to primitive arthropods, such as the trilobites, the tadpole shrimp are celebrities. Their dried eggs are sold in tiny boxes and you can grow your own!