The flying fish and the ocean sunfish just became cousins in the LRT

Figure 1. Flying fish (Exocoetus) skull.

Figure 1. Flying fish (Exocoetus) skull.

This one caught me by surprise, too.
It came about because I re-examined the details.

Superficially
the speedy flying fish (Exocoetus, Fig. 1) seems to have little in common with the lethargic ocean sunfish (Mola, Fig. 2) and opah (Lampris, Fig. 3). Traditionally flying fish nest with speedy needlefish, like Tylosurus. The large reptile tree (LRT, 1647+ taxa) adds 25 more steps to move Exocoetus next to Tylosurus.

Figure 4. Mola mola is a relative of Diodon in the LRT. It has no circumorbital bones, but as a hatchling has pufferfish proportions and spines.

Figure 2. Mola mola is a relative of Diodon in the LRT. It has no circumorbital bones, but as a hatchling has pufferfish proportions and spines.

Skeletal details 
provide a different hypothesis of interrelationships. You can see a short deep mandible and a deep coracoid in these three taxa (Figs. 1-3), along with a long list of other homologous traits.

Figure 2. More traits unite the opah with the flying fish than separate these two, given the present taxon list.

Figure 3. More traits unite the opah with the flying fish than separate these two, given the present taxon list. Note the deep coracoids, as in birds and pterosaurs, here again used to flap the pectoral fins.

All three taxa are derived from
the speedy high-fin amberjack, Seriola rivoliana.

Figure x. Subset of the LRT focusing on basal vertebrates (= fish).

Figure x. Subset of the LRT focusing on basal vertebrates (= fish).

Exocoetus volitans (Linneaus 1758; up to 30cm ) is the extant blue flyingfish, here related to the much larger and nonvolant opah, Lampris (above). Exocoetus travels in schools or schoals. Sometimes they exit the water to avoid predators. Juveniles have a relatively shorter torso. Hatchlings are slow-moving and tiny. Distinctly flying fish and their relatives have a jaw joint directly below the orbit. The coracoid is larger than the scapula, raising and powering the pectoral fins.


References
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

wiki/Lampris
wiki/Almaco_jack
wiki/Exocoetus_volitans

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