Urochordata (sea squirts, tunicates; phylum Chordata) A subphylum that has a reliable fossil record from the Permian, and possible remains in Silurian sediments. Urochordates have tadpole-like larvae with notochords in their tails and a dorsal, tubular nerve cord, features that link them with the Chordata. The adults have a gelatinous or leathery protective test (the tunic) made from a ...
Chordata Chordata is a large and diverse group of animals, with roughly 50,000 living species included. The majority of chordates belong to a group called Vertebrata. Vertebrates have backbones that are composed of vertebrae. Some examples of vertebrates are sharks, fish, dinosaurs, and human beings. A second group of chordates, called Urochordata, consists of animals found mostly in oceans ...
Chordates Chordates are a diverse group of animals that comprise the phylum Chordata. The phylum is divided into three subphyla based on general physical characteristics: Urochordata, Cephalochordata, and Vertebrata. Urochordates have a notochord (a hollow dorsal nerve cord) while in the larvae stage but lose it later in their adult stage. Source for information on Chordates: The Gale ...
Ascidiacea (sea squirts; subphylum Urochordata) A class of sea squirts, most of which inhabit shallow waters where they attach themselves to such structures as rocks, pilings, the bottoms of ships, and coral reefs. Deep-water species inhabit soft substrates and are known to occur at depths exceeding 2000 m. Most ascidians are inconspicuous and are often covered by smaller sessile animals ...
Thaliacea (salps; phylum Chordata, subphylum Urochordata) A class of tunicates in which two siphons occur at opposite ends of the body, so the current of water passing through the animal is used for gas exchan Source for information on Thaliacea: A Dictionary of Zoology dictionary.