Classification of agnathan fish
What are the classes of Agnatha?
agnathan, (superclass Agnatha), any member of the group of primitive jawless fishes that includes the lampreys (order Petromyzoniformes), hagfishes (order Myxiniformes), and several extinct groups.
What are two characteristics of agnathans?
The agnathans lack jaws and paired fins. Instead of jaws, they have a cyclostomic (circular) toothed mouth with which they bore into the side of a fish and suck the blood of their victim. Agnathans lack an internal skeleton made of ture bone.
What characteristics separate agnathan fishes from other fishes?
A defining feature of agnathans is the lack of paired lateral appendages or fins. Some of the earliest jawless fishes were the ostracoderms (Greek for “bone-skin”). Ostracoderms were vertebrate fishes encased in bony armor, unlike present-day jawless fishes, which lack bone in their scales.
What are the two classes of jawless fish?
There are two categories of jawless fish: hagfish and lampreys. Hagfish usually feed on dead or dying fish.
What class do lampreys belong to?
lamprey, any of about 43 species of primitive fishlike jawless vertebrates placed with hagfishes in the class Agnatha. Lampreys belong to the family Petromyzonidae. They live in coastal and fresh waters and are found in temperate regions around the world, except Africa.
What is a characteristic of the class Agnatha?
In addition to the absence of jaws, modern agnathans are characterised by absence of paired fins; the presence of a notochord both in larvae and adults; and seven or more paired gill pouches. Lampreys have a light sensitive pineal eye (homologous to the pineal gland in mammals).
What is the class of bony fish?
Class – Osteichthyes
Class – Osteichthyes
Class Osteichthyes includes all bony fishes. Like all fishes, Osteichthyes are cold-blooded vertebrates that breathe through gills and use fins for swimming.
What class do cartilaginous fish belong to?
Class Chondrichthyes
The cartilaginous fishes (Class Chondrichthyes) are one of the major groups of living fishes.
Is Agnatha a class?
Super Class: Agnatha
Members of the agnatha class are probably the earliest vertebrates. Scientists have found fossils of agnathan species from the late Cambrian Period that occurred 500 million years ago. Members of this class of fish don’t have paired fins or a stomach. Adults and larvae have a notochord.
What are the examples of agnathans?
Jawless fish/Lower classifications
Who are the agnathans give some examples?
Agnatha are jawless fish. Lampreys and hagfish are in this class. Members of the agnatha class are probably the earliest vertebrates. Scientists have found fossils of agnathan species from the late Cambrian Period that occurred 500 million years ago.
What are three characteristics of jawless fish?
Features of the jawless fish include a notochord, paired gill pouches, a pineal eye, and a two-chambered heart.
What are the peculiar features of the respiratory system of agnathans?
They have seven gill slits where oxygen diffuse. Agnatha breathe by sucking in water through the mouth and into the pharynx, then release water from the gill slits. Before leaving through the gill slits, water must pass through the feather-like gills.
What clade do hagfishes belong to?
Hagfish
| Hagfish Temporal range: | |
|---|---|
| Superclass: | Cyclostomi |
| Class: | Myxini |
| Order: | Myxiniformes |
| Family: | Myxinidae Rafinesque, 1815 |
What are the 3 types of bony fish?
Living Osteichthyes are divided into three subclasses: Dipnoi, Crossopterygii, and Actinopterygii.