Final answer:
The subphylum Cephalochordata includes lancelets, which are small marine chordates with a notochord, dorsal hollow nerve cord, pharyngeal slits, endostyle, and tail.
Step-by-step explanation:
Members of the subphylum Cephalochordata, commonly known as lancelets or Amphioxus, are small, fish-like marine animals.
These organisms share several key characteristics with the phylum Chordata: they possess a notochord, a dorsal hollow nerve cord, pharyngeal slits, an endostyle, and a tail throughout their adult stage.
Lancelets are suspension feeders and are unique in that the notochord extends into the head, a feature that gives Cephalochordata its name.
These creatures are important for understanding the evolutionary history of chordates as extinct members like Pikaia date back to over 500 million years ago during the Cambrian period.
Living lancelets are often found buried in sand in warm, temperate, and tropical seas.
While they lack a defined brain, their nervous system is largely built around a hollow nerve cord lying above the notochord, underscoring their importance in studies of vertebrate ancestry.
Lancelets exhibit sexual reproduction with separate sexes, releasing gametes into the water for external fertilization.
The anatomy of lancelets, such as their bladelike shape and feeding mechanisms, offers insight into the primitive features of the earliest chordates.
Complete question:
What is the type of Subphylum Cephalochordata - Lancelet, Amphioxus