Lancelet
A small marine chordate in the subphylum Cephalochordata, with a notochord extending the length of its body and no skull or backbone.
Chordate: An animal defined by a notochord, dorsal hollow nerve cord, pharyngeal slits, and post-anal tail at some life stage. Lancelets display the defining chordate features throughout adulthood.
Ciliary feeding: A feeding method in which beating cilia move particles or fluid toward a feeding structure. Cilia help draw food-bearing water through the lancelet’s pharynx.
Chordate evolution: The evolutionary history of chordates, including tunicates, lancelets, and vertebrates. Lancelets help illuminate the early history of chordate body plans.
Evolutionary developmental biology: The study of how evolutionary changes arise through changes in development. Lancelet embryos help compare ancestral chordate development with vertebrate development.
Tunicate: A marine chordate in the subphylum Tunicata, often sessile as an adult and encased in a tunic. Adult tunicates often lose or remodel chordate traits that lancelets retain.
Notochord: A flexible, rod-like support structure found in chordate embryos and retained throughout life in some chordates. It runs from head to tail and supports the lancelet’s swimming movements.
Endostyle: A mucus-secreting groove in the pharynx of some chordates that captures food particles. Its mucus traps suspended particles as water flows through the pharynx.
Pikaia: An extinct, slender animal from the Cambrian Burgess Shale, often interpreted as an early chordate. Its fossils preserve a body plan compared with that of lancelets.
Branchiostoma floridae: A species of lancelet native to the western Atlantic and widely used in genomic research. Its sequenced genome supports comparisons with vertebrates and other chordates.
Vertebrate: A chordate with a vertebral column or its evolutionary precursor and a skull. Lancelets lack the skull and backbone that define vertebrates.