An aquatic living fossil with ancient origin and many primitive characters, which respires through book gills, is

Question

An aquatic living fossil with ancient origin and many primitive characters, which respires through book gills, is (A) Limulus (B) Cancer (C) Lucifer (D) Daphnia

Tardigrade Admin · Accepted Answer

Limulus or king crab is a large sized marine arthropod which represents a specialized group of chelicerate animals. It has remained almost unchanged since the last 200 million years. It is therefore, also called living fossil. Book gills serve the function of respiratory organs in Limulus.

Q. An aquatic living fossil with ancient origin and many primitive characters, which respires through book gills, is

Limulus

Cancer

Lucifer

Daphnia

Limulus or king crab is a large sized marine arthropod which represents a specialized group of chelicerate animals. It has remained almost unchanged since the last $200$ million years. It is therefore, also called living fossil. Book gills serve the function of respiratory organs in Limulus.