This time we are covering the first major group that will take more than one image to illustrate, the Anaspida. They get their name which in Latin means "shield less ones" from the fact they have fairly small scales that do not form a shield like set of armor compared to other Ostracoderms (A Paraphyletic group we'll cover later.
Speaking of taxonomy there is quite a bit of contention here. Once thought to be the direct ancestors of the lamprey this is no longer thought to be the case with the much smaller clade we met last time, the Euphanerida, likely being the candidate.
In terms of their anatomy I mentioned their scales before but it is believed to have helped them swim more effectively. They also developed the first paired fins in a manner independent of other groups which were held up by these large spines and extensions of the body wall. As an order they are divided into eight families
That one species being Cowielepis ritchiei which is known from the Cowie Formation in what is the small town of Cowie in Kincardineshire, Scotland and from which it's name comes from. The date of this formation is a bit disputed but estimates range from the Wenlock Epoch of the Silurian 433 mya to the Lochkovian stage of the Early Devonian 419 mya or so.
Top Row: Cowielepis ritchiei, Hoburgilepis papillata
Second Row: Kerreralepis carinata, Maurylepis lacrimans
Third Row: Rytidolepis quenstedtii, Schidiosteus mustelensis
Bottom Row: Silmalepis erinacea, Vesikulepis funiforma
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