Pycnodonts are blunt-toothed barracuda

What are pycnodonts?
Citing Cawley et al 2021, Wikipedia reports, “They are considered to belong to the Neopterygii, but their relationship to other members of that group is uncertain.”

Just tilt down the head of Sphyraena, the barracuda,
and you’ll see similarities to Flagellipina the pycnodont. Then tilt down the head of Flagellipina and you’ll see similiarities to Pycnodus, the original pycnodont (Fig 1).

That’s the way the large reptile tree (LRT, 2315 taxa) recovers these taxa.

Figure 1. Sphyraena, the barracuda, compare to two pycndonts, Flagellipina and Pycnodus. ” data-image-caption=”

Figure 1. Sphyraena, the barracuda, compare to two pycndonts, Flagellipina and Pycnodus.

” data-medium-file=”https://pterosaurheresies.files.wordpress.com/2024/03/sphyraena_flagellipinna_pycnodus588.jpg?w=120″ data-large-file=”https://pterosaurheresies.files.wordpress.com/2024/03/sphyraena_flagellipinna_pycnodus588.jpg?w=410″ class=”size-full wp-image-84803″ src=”https://pterosaurheresies.files.wordpress.com/2024/03/sphyraena_flagellipinna_pycnodus588.jpg?w=584&h=1460″ alt=”Figure 1. Sphyraena, the barracuda, compare to two pycndonts, Flagellipina and Pycnodus. ” width=”584″ height=”1460″ srcset=”https://pterosaurheresies.files.wordpress.com/2024/03/sphyraena_flagellipinna_pycnodus588.jpg?w=584&h=1460 584w, https://pterosaurheresies.files.wordpress.com/2024/03/sphyraena_flagellipinna_pycnodus588.jpg?w=60&h=150 60w, https://pterosaurheresies.files.wordpress.com/2024/03/sphyraena_flagellipinna_pycnodus588.jpg?w=120&h=300 120w, https://pterosaurheresies.files.wordpress.com/2024/03/sphyraena_flagellipinna_pycnodus588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />

Figure 1. Sphyraena, the barracuda, compare to two pycndonts, Flagellipina and Pycnodus.

Pycnodus platessus
(Agassiz 1835; Late Jurassic, 30cm long) is the first known pycnodontiform, a clade traditionally considered extinct, but now known as a clade close to Sphyraena, the extant barracuda and Late CretaceousFlagellipina.

Flagellipinna rhomboides
(Cawley and Kriwet 2019; Late Cretaceous) is traditionally considered a diamond-shaped pycnodontiform fish, but here this angelfish-mimic nests between Sphyraena, the extant barracuda and Pycnodus.

Sphyraena barracuda
(originally Esox sphyraena Linneaus 1758; up to 165cm in length) is the extant barracuda, closely related to other long, fast, sharp-toothed predators, like Tylosurus – and to slow, blunt-toothed coral nibblers, like the pycnodonts.

The process of making discoveries like this is a driving force.

Build your own LRT. You’ll find it a powerful tool for learning.

References
Agassiz JLR 1835. Recherches sur les Poissons fossiles, 5 volumes. Imprimerie de Petitpierre et Prince, Neuchaatel, 1420 pp.
Cawley JJ and Kriwet J 2019. A new genus and species of pycnodontid fish Flagellipinna rhomboides, gen. et sp. nov. (Neopterygii, Pycnodontiformes), from the Upper Cretaceous (Cenomanian) of Lebanon, with notes on juvenile form and ecology. Journal of Vertebrate Paleontology 39(2): e1614012
Cawley JJ et al (6 co-authors) 2021. Rise and fall of †Pycnodontiformes: Diversity, competition and extinction of a successful fish clade. Ecology and Evolution. 11(4): 1769–1796.
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/Flagellipinna – not yet posted
wiki/Pycnodontiformes
wiki/Sphyraena
wiki/Pycnodontiformes