00:01
The given question is the jaw first occurred in which of the following group of fishes.
00:05
The options are lamprey, rayfin fishes, platyperums and lastly contrastines.
00:09
Let us start with the first option that is given is lamprey.
00:16
Lampres do not have jaws however but have a sucking disc for mouth.
00:26
So this option is incorrect.
00:29
Now the second one, the jaws of a ray fin fish.
00:39
Rayfin fish have undergone many modifications through their evolution.
00:43
The neoptery regions, the lost the connection, between the cheekbones and the posterior of the upper jaw.
00:49
So this option is incorrect.
00:53
Let us talk about the placodums.
00:59
Placodoms, it is known as prehistoric armored fishes...