Basal Amiiformes in the LRT

The bowfin, Amia, usually nests alone
or with unrelated taxa (e.g. Polypterus) in traditional fish phylogenies.

Not here, in the LRT, where Amia has a long list of descendants. These examples (Fig 1) are toothy. long-bodied predators originating in fresh waters then transitioning to marine environs. Some labels have changed from the days of Gregory 1933 based on comparative anatomy shown here in standard DGS colors.

Figure 1. Amia and its phylogenetic descendants in the LRT. Note the change of labels in Esox in Tylosurus where the postorbital (amber) extends further anterior to the orbit and the former palatine is re-identified as a lacrimal (tan). Note the splitting of the supratemporals (green) in Esox creating a ‘scale bone’. These changes have not come easy, but become apparent in charts of comparative anatomy like this one.

Amia looks different
and was classified as different because it is so primitive. Of course, every taxon in the LRT is related, more or less, to every other taxon, even Amia.

Amia calva
(Linneaus 1766; up to 70cm in length) is the extant bowfin, a basal fish able to breathe both water and air. Hatchlings look like tadpoles. Deep lips rim the long teeth. Females produce 2000 to 5000 eggs. Fossil relatives of Amia have a worldwide distribution in fresh and salt waters.

References
Gregory WK 1933. Fish skulls. A study of the evolution of natural mechanisms. American Philosophical Society 23(2) 1–481.
Linneaus C von 1766. Sysema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio duodecima, reformata. pp. 1–532. Holmiæ. (Salvius) .

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