Cladocera and Other Branchiopoda

This chapter focuses on the class Branchiopoda, which includes the common Daphnia, and other members of the suborder Cladocera (order Diplostraca). Branchiopods are a heterogeneous group linked by similar mouthparts and leaf-like thoracic legs (phyllopods). Virtually all species within the eight extant orders of Branchiopoda are limited to inland waters (mostly freshwater lentic systems). Branchiopods occupy key positions in aquatic communities. As consumers, they are algivorous herbivores, detritivores (often assimilating bacteria on benthic or suspended organic matter), and occasionally predators of small invertebrates. They are important prey items in the diets of many fish, waterfowl, and certain other vertebrate and invertebrate predators. Many species are planktonic while others live in shallow water benthic habitats. Some, like the fairy shrimp Artemia, are adapted to temporary ponds and to hypersaline ponds and lakes. Scientists estimate that the United States and Canada contain ?645 species of cladocera and nearly 100 species of the generally larger, noncladoceran branchiopods. This chapter introduces the general biology, morphology, phylogeny, evolution, ecology, physiology, and classification of Branchiopods, with focus on those found in freshwaters of North America.