Odd Carboniferous Harpacanthus updated

The hypothesis that the six toothy elements
were gill bars with teeth, as in moray eels (Fig 5), continues today. Overall a better match was found in Neoclinus, which has toothy gill bars (Fig 3), but lacks the ability to move them. Sans the rest of the skeleton, in 1886 these curved toothy bars were the first loose parts of this taxon known leading to much speculation as to what sort of animal they belonged to until Lund and Grogan published in 2004.

Lund and Grogan 2004 produced
a Harpacanthus diagram (Fig 1, upper image) that was modified here a few years ago (Fig 1, lower image). That first attempt included several errors rectified today (Fig 2). Corrections are a continuing process here and hopefully elsewhere, too.

This new nesting also appears to be a novel hypothesis of interrelationships.
If not, please provide a citation so I can promote it here.

References
Lund R and Grogan E 2004. Five new euchondrocephalan Chondrichthyes from the Bear Gulch Limestone (Serpukhovian, Namurian E2b) of Montana, USA. In G. Arratia, M. Wilson, R. Cloutier (eds.), Recent Advances in the Origin and Early Radiation of Vertebrates 505-531.
Traquair RH 1886. On Harpacanthus, a new genus of Carboniferous Selachian Spines. Journal of Natural History. Series 5. 18(108): 493–496.