How many species of Cephalochordata are there?

How many species of Cephalochordata are there?

Acrania, or Cephalochordata, is a taxon of marine invertebrate chordates comprising 30 species belonging to three genera, Branchiostoma, Epigonichthys, and Asymmetron ( Poss and Boshung 1996 ).

What are the classes of Cephalochordata?

The subphylum Cephalochordata comprises a single family Brachiostomatidae with two genera Branchiostoma (Costa, 1834) and Asymmetron (Andrews, 1893).

What are the examples of cephalochordates?

Cephalochordate/Lower classifications

What makes cephalochordates unique?

Several features unique to cephalochordates and vertebrates suggest that they are “sister groups” more closely related to each other than either is to other chordates. These features include the segmented musculature and its innervation, the pattern of circulation, and several biochemical features.

What is the common name of Cephalochordata?

A cephalochordate (from Greek: κεφαλή kephalé, “head” and χορδή khordé, “chord”) is an animal in the chordate subphylum, Cephalochordata. They are commonly called lancelets.

Why are cephalochordates called so?

General features. The lancelets are also called cephalochordates (Greek: kephale, “head”) because the notochord extends from near the tip of the tail to well into the anterior of the body.

What are the three classes of subphylum Urochordata?

The Subphylum Urochordata includes a large number of species which exhibit high degree of biological diversities. The members are classified under three classes: Ascidiacea, Thaliacea and Larvacea or Appendicularia.

What is the phylum of Cephalochordata?

ChordateCephalochordate / Phylum

Are hagfish cephalochordates?

Cephalochordata (or lancelets, traditionally known as amphioxus, plural amphioxi) is a subphylum of marine invertebrates of the phylum Chordata. They are usually found in shallow parts of temperate or tropical seas….Cephalochordata.

Kingdom: Animalia
Phylum: Chordata
Subphylum: Cephalochordata Owen, 1846

Are cephalochordates exclusively marine?

Cephalochordata is the subphylum of Protochordata. They are lower vertebrates, do not have a cranium, vertebral column, and skull. They are marine animals. They have the three primary chordate characters- Notochord, dorsal hollow nerve cord, and paired gill slits.

Are cephalochordates filter feeders?

The cephalochordates like Amphioxus and lancelets are called filter feeders. Cephalochordates have developed a filter-feeding system is called the oral hood, it serves as the entrance for the incoming food particles. The free edge of the oral hood contains Buccal cirri and a small filament.

Do cephalochordates have hearts?

Circulatory system The most notable difference is that cephalochordates lack a heart. Blood is forced through the closed system by contractile blood vessels (especially one called the ventral aorta) and by blood vessels of the gills.

Does cephalochordates have a brain?

The central nervous system of the cephalochordates is very simple. A dorsal nerve cord extends through the length of the body, giving rise to segmentally arranged nerves. No brain is detectable. The skin is rich in sensory nerve endings that probably help produce a sense of touch and are important for burrowing.

What is the difference between Urochordata and Cephalochordata?

The main difference between Urochordata and Cephalochordata is the location and presence of notochord. In urochordates, the notochord is present in the larval tail, whereas, in cephalochordates, the notochord is present throughout the life and extends from the head to the tail region.

How many species of tunicates are there?

3,000 tunicate species
About 3,000 tunicate species are found in salt water habitats throughout the world.

Are tunicates cephalochordates?

Tunicates or urochordates (appendicularians, salps and sea squirts), cephalochordates (lancelets) and vertebrates (including lamprey and hagfish) constitute the three extant groups of chordate animals.

Why are cephalochordates called amphioxus?

Known as lancelets or as amphioxus (from the Greek for “both [ends] pointed,” in reference to their shape), cephalochordates are small, eel-like, unprepossessing animals that spend much of their time buried in sand.

Do Cephalochordates have hearts?

How do Cephalochordates feed?

Cephalochordates have developed a filter feeding system, called the oral hood, that serves as the entrance for incoming food particles. The free edge of the oral hood contains Buccal cirri, small filament-like projections, that assist in sifting out larger food particles before they enter the buccal cavity.

How do cephalochordates reproduce?

Cephalochordates reproduce by releasing their eggs and sperm into the water, where they are fertilized externally. The fertilized eggs develop into free-swimming larvae that drift in the water for up to 200 days, feeding on plankton and other suspended matter, before settling down as adults.