What are the 2 types of Osteichthyan?
Osteichthyan Diversity. Two major living groups: Actinopterygii (Devonian – Quaternary) – Living ray-finned fish and their fossil relatives. Sarcopterygii (Silurian – Quaternary) – living lobe-finned fish (including tetrapods) and their fossil relatives.
What are differences between Ray-finned fish and lobe-finned fish?
The lobe-finned fish are characterized by fleshy lobed fins, as opposed to the bony fins of the ray-finned fish. They also possess two dorsal fins with separate bases, as opposed to the single dorsal fin of ray-finned fish. All lobe-finned fishes possess teeth covered with true enamel.
Are dinosaurs Sarcopterygii?
The group Tetrapoda, a superclass including amphibians, reptiles (including dinosaurs and therefore birds), and mammals, evolved from certain sarcopterygians; under a cladistic view, tetrapods are themselves considered a group within Sarcopterygii.
Are tetrapods Sarcopterygii?
The Sarcopterygii, or lobe-finned fishes, is a clade containing the coelacanths, lungfishes, tetrapods, and their fossil relatives, including the osteolepiformes and panderichthyids.
What are the 3 types of bony fish?
Living Osteichthyes are divided into three subclasses: Dipnoi, Crossopterygii, and Actinopterygii.
Are sexes separate in Osteichthyes?
Sexual maturity means that they are capable of producing offspring. Through this process, most Osteichthyes develop into either males or females. There are some hermaphroditic Osteichthyes, meaning they have both male and female sex organs, but they do not make up the majority of this class.
What is the difference between bony and cartilaginous fish?
Technically, the most obvious disparity between bony vs cartilaginous fish comes from the fact that the skeleton of bony fish is made of bones alone, while that of cartilaginous fish is made of cartilage. There are more than 20,000 fish species in the world. Of the class Chordata, Pisces is a super class.
Are birds Sarcopterygii?
Sarcopterygii are the lobe-finned fishes and, on the basis of their shared evolutionary ancestry (cladistics), comprise lungfishes, coelacanths, and the tetrapods (amphibians, reptiles, birds, and mammals).
Are Sarcopterygii extinct?
Not extinct
Lobe-finned fish/Extinction status
Are Actinistia tetrapods?
Among living fish, the coelacanth Latimeria chalumnae (Actinistia), which is the only recent representative of the Crossopterygii (Actinistia and Rhipidistia), the lungfish (Dipnoi) and ray-finned fish (Actinopterygii), have each been considered as sister-groups of the tetrapods.
Why are Acanthostega and Ichthyostega called fish like tetrapods?
In a nutshell, the “fish–tetrapod transition” usually refers to the origin, from their fishy ancestors, of creatures with four legs bearing digits (fingers and toes), and with joints that permit the animals to walk on land.
What are the 4 classes of fish?
Classification of Fish. There are about 28,000 existing species of fish, and they are placed in five different classes. The classes are commonly referred to as hagfish, lampreys, cartilaginous fish, ray-finned fish, and lobe-finned fish (see the table in the previous lesson).