Updated April 23, 2020
by adding taxa. This moved the moray eel, Gymnothorax (Fig. 2, 3), to nest with tiny Gregorius (Fig. 1), the outgroup taxon to all other bony fish.
Figure 1. Tiny Gregorius rexi nests basal to moray and gulper eels and also basal to all bony fish in the LRT.
you can see the origin of the long straight tail of the moral eel evolving from the straight/diphycercal tail of Gregorius. The lateral fins are missing in the moray eel. Gregorius is a suitable predecessor despite its late appearance in the Early Carboniferous after a likely Late Silurian radiation.
Figure 2. Moray eel skeleton. Note the two gray dots represent absent fins. The apparent second set of jaws are gill bars able to jump forward to grab bitten prey and pull it back to the esophagus.
Many hundreds of millions of years have passed since the Devonian.
In the meantime one branch of lobefins gave rise to dinosaurs, bats, and blog readers. Another branch gave rise to most ray-fin fish. A third branch, a basal branch, gave rise to Gymnothorax, a newly recovered basalmost bony fish that lost several facial bones and four fins since the Devonian. What remains is a scale-less eel with a bad reputation.
Figure 3. The skull of the moray eel, Gymnothorax, in 3 views. Colors added as homologs to tetrapod skull bones. The nares exit is above the eyes.
Compare the snake-like skull of Gymnothorax
(Fig. 3) to Boa (Fig. 4). The convergence is remarkable.
Figure 4. Boa constrictor skull from 4 angles. Note the similarities, by convergence, to the Gymnothorax skull in figure 2.
Figure x. Subset of the LRT focusing on basal vertebrates. This represents the latest hypothesis of interrelationships and includes several changes from prior versions of this section.
Gymnothorax afer (Bloch 1795, type genus) Gymnothorax funebris (Ranzani 1839) is the extant green moray eel, which has no limbs or fins and traditionally nests within the Teleostei. Here this 2m eel nests with Gregorius, a much more primitive node than basal Teleostei. Several cheek bones are also reduced or missing. Note the elongate torso (Fig. 1), prior to the anterior chevrons. That is a primitive trait in vertebrates.
Figure 6. GIF animation showing the dual bite of the dual jaws in moray eels. Both are derived from gill bars. Note: this makes Gymnothorax one of the few fish with a neck, prior to what would have been the pectoral girdle. Seahorses are another. The external naris exit is that little pipe above the orbit. This skull is an inaccurate cartoon. The naris does not perforate the skull at midline nor is the skull split at midpoint in reality. Compare to figure 2.
Bloch ME 1795. Naturgeschichte der ausländischen Fische. Berlin. v. 9. i-ii + 1-192, Pls. 397-429.