Xiphactinus has living relatives in the Amazon

Short one today
because all the work is not yet done with regard to ray fin fish phylogeny. This is just an update.

Previously I overlooked this novel hypothesis of interrelationships.
Now it seems obvious (Fig. 1). But first I had to better understand the crushed skulls of Xiphactinus (Figs. 1, 3) and Portheus (a traditionally junior synonym for Xipactinus, here resurrected due to several differences in the skull and post-crania, Figs. 2,4). Lots of little nips and tucks here.

Figure 1. Revised skull of Xiphactinus.

Figure 1. Revised skull of Xiphactinus.

Figure 2. Revised skull of Portheus.

Figure 2. Revised skull of Portheus.

Figure 2. Xiphactinus fossil. The famous fish-within-a-fish. Note the posterior pelvic fins.

Figure 3. Xiphactinus fossil. The famous fish-within-a-fish. Note the posterior pelvic fins.

Figure 4. Skeleton of Portheus.

Figure 4. Skeleton of Portheus, close to but distinct from Xiphactinus. 

Figure 1. The araimaia, Hopolerythrinus, enters the LRT with the piranha, Serrasalmus.

Figure 5. The araimaia, Hopolerythrinus, nests with the Cretaceous giants, Xiphactinus and Portheus (Figs. 1–4).

Figure 3. Araimaia (Hoplerythrinus) skull.

Figure 6. Araimaia (Hoplerythrinus) skull.

At present these three taxa
share a last common ancestor with an ancestor to Serrasalmus, the piranha.

Figure 8. Subset of the LRT focusing on ray fin fish. Eel-like taxa are highlighted.

Figure 7. Subset of the LRT focusing on ray fin fish. Eel-like taxa are highlighted.

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