Pisces (lat. Pisces) is an extensive group of aquatic maxillofacial vertebrates, previously considered a superclass. Fish are characterized by gill respiration at all stages of postembryonic development of the organism. From the point of view of cladistics, quadrupeds are specialized lobe-finned fish. However, since traditionally the concept of "fish" refers to a paraphyletic group that does not include quadrupeds, there are no fish as a taxon in modern taxonomy.

Fish live in both salty and freshwater reservoirs — from deep oceanic depressions to mountain streams. Fish play an important role in most aquatic ecosystems as a component of food chains. Many species of fish are eaten by humans and therefore have an important commercial value.

Title

The word "fish" (Old Russian. fish) comes from the Proto-Slavic ryba of unclear etymology. It is compared with D.-V.-N. rûrra, rûpa "caterpillar", also "burbot", cf.-v.-N. ruppe, rûpe "burbot". According to Fasmer, the word is a taboo name instead of the older zv, cf. lit. žuvìs "fish", Greek. ἰχθῦς (cf. ichthyology — "the science of fish") "fish", arm. jukn, which, due to consonance with the verb "to call", the fishermen tried not to use.

The Latin name of the fish, pisces, unit. ch. piscis, comes, apparently, from the Proto-Indo-European * pisk-, from which the English fish, that is, "fish", also originated

Classification

In early classifications, fish were considered as a class or superclass of vertebrates, which included all known groups of cartilaginous, bony and other fish. Currently, taxonomists consider fish as a paraphyletic group, since in addition to the others, lobe-finned fish are included in it, among the fossil representatives of which were the ancestors of terrestrial vertebrates — tetrapods (Tetrapoda), which are not fish.

Modern fish are divided into 3 classes: cartilaginous, ray-finned and lobe-finned fish. Back in the second half of the XX century, the last two groups were included as subclasses in the class of bony fish, but in recent decades, most ichthyologists have considered them as independent classes. Nevertheless, some reputable researchers in recent years tend to combine ray-finned and lobe-finned fish into one class of Osteichthyes again.

The relationships of the main subgroups of fish are presented below:

Pisces

Class Placodermi — Shelled fish, or placoderms †

Chondrichthyes class — Cartilaginous fish

Acanthodii class — Acanthodes †

Superclass Osteichthyes — Bony fish

Class Actinopterygii — Ray - finned fish

Class Sarcopterygii — Lobe - finned fish

Pisces (lat. Pisces) is an extensive group of aquatic maxillofacial vertebrates, previously considered a superclass. Fish are characterized by gill respiration at all stages of postembryonic development of the organism. From the point of view of cladistics, quadrupeds are specialized lobe-finned fish. However, since traditionally the concept of "fish" refers to a paraphyletic group that does not include quadrupeds, there are no fish as a taxon in modern taxonomy.

Fish live in both salty and freshwater reservoirs — from deep oceanic depressions to mountain streams. Fish play an important role in most aquatic ecosystems as a component of food chains. Many species of fish are eaten by humans and therefore have an important commercial value.

Title

The word "fish" (Old Russian. fish) comes from the Proto-Slavic ryba of unclear etymology. It is compared with D.-V.-N. rûrra, rûpa "caterpillar", also "burbot", cf.-v.-N. ruppe, rûpe "burbot". According to Fasmer, the word is a taboo name instead of the older zv, cf. lit. žuvìs "fish", Greek. ἰχθῦς (cf. ichthyology — "the science of fish") "fish", arm. jukn, which, due to consonance with the verb "to call", the fishermen tried not to use.

The Latin name of the fish, pisces, unit. ch. piscis, comes, apparently, from the Proto-Indo-European * pisk-, from which the English fish, that is, "fish", also originated

Classification

In early classifications, fish were considered as a class or superclass of vertebrates, which included all known groups of cartilaginous, bony and other fish. Currently, taxonomists consider fish as a paraphyletic group, since in addition to the others, lobe-finned fish are included in it, among the fossil representatives of which were the ancestors of terrestrial vertebrates — tetrapods (Tetrapoda), which are not fish.

Modern fish are divided into 3 classes: cartilaginous, ray-finned and lobe-finned fish. Back in the second half of the XX century, the last two groups were included as subclasses in the class of bony fish, but in recent decades, most ichthyologists have considered them as independent classes. Nevertheless, some reputable researchers in recent years tend to combine ray-finned and lobe-finned fish into one class of Osteichthyes again.

The relationships of the main subgroups of fish are presented below:

Pisces

Class Placodermi — Shelled fish, or placoderms †

Chondrichthyes class — Cartilaginous fish

Acanthodii class — Acanthodes †

Superclass Osteichthyes — Bony fish

Class Actinopterygii — Ray - finned fish

Class Sarcopterygii — Lobe - finned fish