Definition
noun, plural: lancelets
A small fishlike chordate of the taxonomic order Amphoxiformes
Supplement
The lancelets are small fishlike chordates of the order Amphoxiformes. The Amphoxiformes belongs to class Leptocardii of the subphylum Cephalochordata (cephalochordates). The lancelets serve as the modern representatives of this subphylum. Other members of cephalochordates are already extinct. One of the distinctive features of the cephalochordates is the rudimentary condition of the species’ organs. Thus, searching for fossilized specimens of these species is difficult.
The lancelets as a chordate possess a notochord, a dorsal nerve cord, an endostyle, a pharynx, and a post-anal tail. The notochord of lancelets, unlike other chordates, persists till adulthood. Other chordates have a vertebral column that replaces the notochord during embryonic development.
There are about 32 species of lancelets and one of them is Branchiostoma (Amphioxus) lanceolatus, a marine cephalochordate. This species is used as a model organism in various studies such as evolution and taxonomy. Apart from research studies, the lancelets are also used commercially as food for humans and domesticated animals.
Scientific classification:
- Kingdom: Animalia
- Phylum: Chordata
- Subphylum: Cephalochordata (Haeckel, 1866)
- Class: Leptocardii (Müller, 1845)
- Order: Amphoxiformes
Other common name(s):
- amphioxus
See also:
- chordate
- cephalochordate
