The number of living fish species is over 26,400 which is 51.9% of almost all vertebrates. Like other vertebrates, fish have an unequal abundance and diversity. Their ancestors were widespread 500 million years ago. They spread through a massive time-wide evolution and had the opportunity to originate and become extinct in major phyletic streams, even … Read more
Teleost is a diverse group of ray-finned fishes which belongs to largest infraclass Teleostei under the class Actinopterygii. The group teleost includes 40 orders and 448 families with over 26000 species. They are the most advanced fish among the bony fishes. The world`s important sport and commercial fishes include this group. The length of the … Read more
Fish are the prime aquatic animals. Because only fish have evolved there in the aquatic environment with origin. The origin and development of any other vertebrate species have not been completed in the aquatic environment. Various changes have been made in the anatomical and physiological functions of fish for successful adaptation to the aquatic environment. … Read more
According to E.O. Wilson, there are 1.7 million species in the world. At present, this number is considered a small part of the world’s biodiversity. There are 751,000 species of insects known worldwide, including 112,000 species of Lepidoptera, 103,000 species of Hymenoptera, and 290,000 species of Coleoptera. There are also 290,000 beetle species. On the … Read more
The sac-like structure between the intestines and the kidneys of most fish is called a swimbladder. However, many times it is also called gas or air sac. It contains a mixture of carbon dioxide (CO2), oxygen (O2) and nitrogen (N2) gases. With the exception of a few areas, almost all bony fish contains swimbladder. The … Read more
Scoliodon is an Indo-Pacific species which belongs to the family Ceacharrhinidae under order Carcharhiniformes of Class Elasmmobranchii. It has an elongated and spindle-shaped body which tappers at the end. The head is dorso-ventrally compressed with laterally compressed trunk and tail. The mouth is situated on the ventral side and the entire body is covered by … Read more