posterior root the posterior, or sensory, division of each spinal nerve, attached centrally to the spinal cord and joining peripherally with the anterior root to form the nerve before it emerges from the intervertebral foramen; each posterior root bears a spinal ganglion that conveys sensory fibers to the spinal cord.he sensory division of each spinal nerve, attached centrally to the spinal cord and joining peripherally with the ventral root to form the nerve before it emerges from the intervertebral foramen.
Most published information about the life span of saltwater fish are from public aquariums where the fish are kept in the best possible conditions. Many saltwater fish succumb to illness early in life due to poor husbandry. Some saltwater species only live an average of 2 to 4 years.
Little is known about how the fish lives, what it eats, how it reproduces, or how many of them are left. The new discovery was based on dissections (pictured) and scans of infant and adult coelacanth samples, as well as 3D reconstructions.he structure is of no use to the living species, which, like all other fish, breathes using gills. Coelacanth fossils have been dated to around 400 million years ago and the species was thought to have died out towards the end of the Mesozoic era, which stretched from 250 to 66 million years ago.