But seriously, strict taxonomy at higher levels is really messy and groups like Holocephali (the sub-class containing Chimeras) is essentially a catch-all taxon that isn’t well supported. I’ve seen plenty of gene trees that support Elasmos and Holos as a single subclass (there’s less diversity between them than there is within other chordate subclasses).
Ratfishes are not elasmobrachs either… just sayin’…
Ratty just feels left out. Why do y’all always have to exclude him during the holidays?!
But seriously, strict taxonomy at higher levels is really messy and groups like Holocephali (the sub-class containing Chimeras) is essentially a catch-all taxon that isn’t well supported. I’ve seen plenty of gene trees that support Elasmos and Holos as a single subclass (there’s less diversity between them than there is within other chordate subclasses).
This paper has some nice trees that illustrate that: http://onlinelibrary.wiley.com/doi/10.1002/jez.b.21293/pdf