Question

Which fish is known as a living fossil?
A) Chimaera
B) Latimeria
C) Pristis
D) Harpodon

Answer 1

Hint: The term living fossils was first used by Darwin to describe organisms which were anomalous, meaning that new forms were very slowly formed. However this term is now used to describe species that were found first as fossils before the living example was discovered.

Complete answer:
Option B is the correct answer. Latimeria is known as such as it is the only known surviving member of its taxon. It is estimated to have evolved around 400 million years ago. This means that genetically it has not undergone significant changes.
Chimaera are now as ghost sharks, and are fish with a cartilaginous skeleton. Though they have been around since the Devonian period, they are related to sharks and rays, and are thus not living fossils. Option A is incorrect.
Pristis belong to the Sawfish genus, and members of this group are found all over the world in warmer waters, both freshwater and saline. They are not living fossils, but are on the verge of extinction. Option C is incorrect.
Harpodon may be a very unusual looking fish, but it belongs to a family known as lizard fish. It is commonly called Bombay duck. This is a commercially important species of fish. Option D is incorrect.

Hence the correct answer is OPTION(B)

Note: Latimeria may sound new, but they have been more commonly known as Coelacanths. There are some morphological differences between actual coelacanth fossils, and the living Latimeria, but this definitely did not occur at the same rate as other lines of vertebrate families.