Keeping amphioxus in the laboratory: an update on available husbandry methods.

Cephalochordates, commonly known as amphioxus or lancelets, are small, marine animals that can be found in coastal habitats of temperate, subtropical, and tropical waters. Together with vertebrates and tunicates, the cephalochordates belong to the chordate phylum, whose members are characterized by a number of conserved morphological features, such as a dorsal nerve cord, a notochord, a pharynx, a segmented musculature as well as a post-anal tail. Due to their basal position within the phylum, cephalochordates have become essential models for studying the evolutionary origin and diversification of vertebrates. Here, we present the currently available methods for maintaining and rearing cephalochordates in a laboratory environment, focusing on five species: the European amphioxus (Branchiostoma lanceolatum), the Florida amphioxus (Branchiostoma floridae), the Chinese amphioxus (Branchiostoma belcheri), the Japanese amphioxus (Branchiostoma japonicum), and the Bahamas lancelet (Asymmetron lucayanum). In addition to reviewing the protocols for capture, transport, aquaculture, and feeding of adults, we discuss methods for controlling gonad development and spawning, as well as for growing embryos and larvae. This information is complemented by observations from our animal facility on the European amphioxus (Branchiostoma lanceolatum). In sum, this work summarizes the latest advances in cephalochordate animal husbandry and highlights challenges for improving the use of these animals as laboratory model systems.