Anatrepis - Anatrepis

Japanese: アナトレピス - あなとれぴす

…a general term for fishes with hard exoskeletal armor that lived in the Paleozoic Era, including the jawless ostracoderms and jawed placoderms. The oldest is Anatolepis , found in the Late Cambrian strata. The armor of a typical armored fish is made up of three layers: an outer dentate layer, a bony middle layer, and a basal layer.

From [Pteraspis]

…The Pteraspis family includes the oldest vertebrate fossils in the world. Anatolepis , discovered in the late Cambrian strata of Wyoming, USA, is one such fossil. The body of Pteraspis is covered with bony armor. …

From [Agnatha]

...A fish about 10 to 40 cm long that lived from the Silurian to Devonian periods, its body is flattened vertically and covered with small protrusions like shield scales. The oldest fish in the world is the Anatolepis genus of the Pterotophore subclass, discovered in a late Cambrian layer. [Ueno Teruya]...

*Some of the terminology explanations that mention "Anatrepis" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…古生代に生息した固い外骨格の装甲をもつ魚類の総称で，無顎綱の甲皮類ostracodermやあごのある板皮綱Placodermiに属する魚類が含まれる。最も古いものはカンブリア紀後期の地層から発見されているアナトレピスAnatolepisである。典型的な甲冑魚の装甲は3層からできており，外側の歯質の層と骨質の中層と基底層からなる。…