Dictionary > Cephalochordate

Cephalochordate

Definition
noun, plural: cephalochordates
Any of the small, elongated, segmented, fish-like chordates that belong to the subphylum Cephalochordata, such as lancelets
Supplement
Chordates are primarily characterized by having a notochord, dorsal hollow nerve cord, muscular post anal tail, and pharyngeal slits for at least some period of the life cycle of an animal. The phylum Chordata has three subphyla: Vertebrata (vertebrates), Tunicata (tunicates), and Cephalochordata (cephalochordates).
As a chordate, the cephalochordates possess a notochord. However, their notochord (as well as the dorsal nerve cord, endostyle, pharynx, and post-anal tail) persists till adulthood. Their notochord extends from head to tail. The cephalochordates are small and lack any hard parts. The lancelets (of about 32 species) serve as the modern representatives of this subphylum.
Other species belonging to the subphylum are already extinct. For instance, Pikaia gracilens species were recovered from the Burgess Shale (i.e. a fossil-bearing deposit located in the Canadian Rockies of British Columbia, Canada). They look similar to the lancelet and probably swam like the eels. Cathaymyrus species were found from the Chengjiang County, Yuman Province in China. They possessed an elongated, segmented body but without distinctive head.
Word origin: Ancient Greek kephalḗ (“head”) + chordata
Scientific classification:

  • Kingdom: Animalia
  • Phylum: Chordata
  • Subphylum: Cephalochordata (Haeckel, 1866)

See also:


You will also like...

Genetics – Lesson Outline & Worksheets
Genetics – Lesson Outline & Worksheets

  Topics Modules Quizzes/Worksheets Description Introduction to Genetics Genetics – Definition: Heredity and ..

Bryophytes
Bryophytes

Bryophytes are a plant group characterized by being nonvascular. They include the mosses, the liverworts, and the hornwo..

Plant Water Regulation
Plant Water Regulation

Plants need to regulate water in order to stay upright and structurally stable. Find out the different evolutionary adap..

DNA carries genes coding for proteins
Genetic Information and Protein Synthesis

Genes are expressed through the process of protein synthesis. This elaborate tutorial provides an in-depth review of the..

Physical growth
Physical Development in Humans

This tutorial elaborates on the physical development of humans, particularly from puberty to adulthood. Read this tutori..

bryophyte - sporophyte and gametophyte
Meiosis and Alternation of Generations

Plants are characterized by having alternation of generations in their life cycles. This tutorial is a review of plant m..