Ray fin fish phylogeny, slowly coming into focus

Updated February 11, 2021
with new data some taxa are reordered.

Every day there are changes 
in the ray-fin fish subset of the large reptile tree (LRT, 1796+ taxa). This constant involvement, day-after-day has been as rewarding as frustrating. Earlier we looked at some of the more interesting and unexpected pairings. Here (Fig. 1) is the latest iteration:

Figure x. Rayfin fish cladogram

Figure x. Rayfin fish cladogram

This, then, is a step back to look at the clade in toto,
to see if any taxa or clades don’t belong together. I don’t profess that this cladogram is finished or perfect. Rather, it is presented to expose its frailties in order to repair them.

Some takeaways (at present):

  1. Basalmost taxa are derived from Gregorius and the moray eel clade
  2. Basalmost taxa retain teeth on the maxilla and the parietals are not separated medially
  3. Basalmost taxa are related to spiny sharks on the other bony fish clade, the one that leads to placoderms, catfish, lobefins and tetrapods
  4. Basalmost taxa skew toward a deep sea niche today, perhaps not in the past
  5. Basalmost taxa radiated in the Late Silurian to Early Devonian
  6. Xiphactinus represents the largest size attained by tested clade members
  7. Sea horses, like Hippocampus, are among the smallest and least similar to ancestral taxa
  8. The loosening of the maxilla occurred by convergence several times
  9. The appearance of the palatine as a cheek bone occurred several times
  10. Basalmost taxa are generally small and slow. Transitional taxa are speedy, open-sea predators. Derived taxa return to bottom-dwelling sit-and-wait predation
  11. Some basal taxa (e.g. Amia) can breathe air. Lepidogalaxias estivates.
  12. Only the mudskipper, Periophthlamus (Fig. 2), crawls out above the surface, keeping its gills bathed with cheekfulls of water. No other ray-fin taxa develop anything like a crawling, lobe-like fin.
Figure 4. The mudskipper, Periophthalmus, nests with the neon goby, Elacatinus, in the LRT.

Figure 2. The mudskipper, Periophthalmus, nests with the neon goby, Elacatinus, in the LRT.

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