Two piranhas nest with the bowfin in the LRT

The extant Amazon river piranha,
Serrasalmus, nests in the large reptile tree (LRT, 1504 taxa; Figs. 1, 2) with the Jurassic pre-piranha, Diapedium (Fig. 3), itself derived from the bottom-dwelling bowfin, Amia (Fig. 4).

Like Amia,
the postorbital and jugal in Serrasalmus form large cheek plates, replacing the lost squamosal.

Dapedium caelatum (Leach 1822; Thies and Hauff 2011; Lower Jurassic; UHH 2) nests as a sister to the extant Amia, but shares more traits with the piranha, Serrasalmus).

Amia calva (Linneaus 1766; up to 70cm in length) is the extant bowfin, able to breathe both water and air. Rather than two dorsal fins, an single elongate undulating fin is present. Hatchlings look like tadpoles. The squamosal and quadratojugal are absent. The lacrimal and jugal break apart into several bones. Females produce 2000 to 5000 eggs. Fossil relatives of Amia have a worldwide distribution in fresh and salt waters.

So far,
the LRT continues to nest taxa as sisters that share a long list of traits. The character list was never designed for fish, but it still works! The present relationships are often different than traditional taxonomic hypotheses of relationships, especially different from genetic analyses.

References
de Lacepéde BG 1803. Histoire naturelle des poissons. Tome Cinquieme. 5(1-21):1-803 + index.
Leach WE 1822. Dapedium politum. P. 45 in HT de la Beche Remarks on the geology of the south coast of England, from Bridport Harbour, Dorset, to Babbacombe Bay,
Devon. Volume 1, Transactions of the Geological Society of London, Series 2. Geological Society of London, London.
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Linneaus C von 1766. Systema 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)
Thies D and Hauff RB 2011. A new species of Dapedium Leach, 1822 (Actinopterygii, Neopterygii, Semionnotiformes) from the EArly Jurassic of South Germany. Palaeodiversity 4:185–221.

wiki/Amia
wiki/Xiphias
wiki/Sphyraena
wiki/Piranha
wiki/Serrasalmus
wiki/Dapedium