Cladoselache kepleri is a flat-head shark close to flat-head placoderms

The phylogenetic line between
traditional sharks and traditonal placoderms continues to intertwine. Case in point (Fig 1): Cladoselache kepleri shares a long list of traits with other flat-head extinct fish.

This is why the LRT (built using tetrapod characters) is about to blow a gasket.
Shark? Or placoderm? It’s a transitional taxon in the LRT.

Figure 1c. Cladoselache kepleri nests with these flathead sharks derived from flathead placoderms in the LRT ” data-image-caption=”

Figure 1c. Cladoselache kepleri nests with these flathead sharks derived from flathead placoderms in the LRT

” data-medium-file=”https://pterosaurheresies.files.wordpress.com/2024/02/gladbachus.dickosteus.fossil588.jpg?w=121″ data-large-file=”https://pterosaurheresies.files.wordpress.com/2024/02/gladbachus.dickosteus.fossil588.jpg?w=412″ src=”https://pterosaurheresies.files.wordpress.com/2024/02/gladbachus.dickosteus.fossil588.jpg” alt=”Figure 1c. Cladoselache kepleri nests with these flathead sharks derived from flathead placoderms in the LRT” class=”wp-image-84251″ />

Some of the images
have been updated from prior postings as learning continues.

Cladoselache kepleri
(Newberry 1889; Dean 1909, Late Devonian; AMNH FF7328, skull length about 26cm) has a shorter, wider skull than Cladoselache fyleri. Currently it nests closer to smaller flat-head sharks and placoderms, like Gladbachus and Dickosteus.

References
Newberry JS 1889. On the fossil fishes of the Eerie shale of Ohio (Abstract). Transactions of the New York Academy of Sciences, 7, 178– 180.

wiki/Cladoselache