Yes that is true as sloss
yes
Ostracoderms were ancient fish with an an armor of bony plates. However, your question is very muddled and therefore we can not answer it properly.
They were jawless fish that lived during the Paleozoic era Stunningly some of our oldest ancestors came from ostracoderms!
Ostracoderms were a group of extinct jawless fishes that lived from the late Cambrian to the end of the Devonian period. They were characterized by their bony armor covering their bodies, lack of jaws, and typically, had a cartilaginous skeleton. Ostracoderms are considered to be among the earliest vertebrates.
Agnatha, also known as jawless fish, are the oldest vertebrate fossils with no jaws. This group includes ancient species like the ostracoderms and the agnathan fish.
They're both extinct bony fishes. The difference is that ostracoderms were jaw-less and placoderms had jaws.
Ostracoderms were a group of early jawless fish that lived in marine environments during the Paleozoic era. They were found in oceans worldwide, with fossil records indicating distribution in regions such as North America, Europe, and Australia.
Lampreys are in the superclass Agnatha, jawless fish. They are of the class Cyclostomata, which includes hagfish, as opposed to the extinct Ostracoderms.
The genus of old red sandstone fish-like creatures is known as Ostracoderms. These ancient jawless fish lived during the Paleozoic era and are characterized by their bony outer covering.
Ordovician Period
lobe-finned fish
Sea horses are vertebrates. They are fish and are descended from pipe fish.