What are the 4 gnathostomes?

What are the 4 gnathostomes?

Among Recent vertebrates, the gnathostomes include sharks, rays, chimaeras, ray-finned fishes, lobe-finned fishes and land vertebrates. Extant gnathostomes fall into two major clades, the Chondrichthyes and Osteichthyes.

What is meant by Gnathostome?

: a vertebrate animal that possesses true jaws.

How many species of gnathostomes are there?

The vast majority of present-day fish belong to this group, which consists of approximately 30,000 species, making it the largest class of vertebrates in existence today. Nearly all bony fish have an ossified skeleton with specialized bone cells (osteocytes) that produce and maintain a calcium phosphate matrix.

Which of the following organisms are gnathostomes?

Animals that possess jaws are known as gnathostomes, which means “jawed mouth.” Gnathostomes include fishes and tetrapods.

What is chondrichthyes and osteichthyes?

Definition. Chondrichthyes refers to a class of fishes that includes those with a cartilaginous skeleton while Osteichthyes refers to a class of fishes that includes those with a bony skeleton.

Which is the best description of the group Gnathostomata?

Classification The group, Gnathostomata, is traditionally a superclass, broken into three top-level groupings: Chondrichthyes, or the cartilaginous fish; Placodermi, an extinct clade of armored fish; and Teleostomi, which includes the familiar classes of bony fish, birds, mammals, reptiles, and amphibians.

Is there a free Merriam Webster dictionary for Gnathostomata?

Start your free trial today and get unlimited access to America’s largest dictionary, with: Ad free! Join Our Free Trial Now! “Gnathostomata.” Dictionary, Merriam-Webster, Accessed 29 Aug. 2021.

Are there any extinct gnathostomes in the tree of life?

In addition, there are two extinct major gnathostome clades, the Placodermi (Early Silurian-Late Devonian) and the Acanthodii (Latest Ordovician or Earliest Silurian – Early Permian). There may be other fossil gnathostome taxa which fall outside of these four taxa.

How are placoderms and Gnathostomata alike and different?

All other gnathostomes share a special arrangement of the eye muscles (the superior oblique eye muscle being attached anteriorly in the orbit), whereas that of placoderms is similar to that in the Osteostraci (the superior oblique eye muscle being attached posteriorly in the orbit).