Brazilichthys macrognathus was a ray-finned fish that lived in Permian estuaries in the northeast of Brazil Pedra de Fogo Formation. It was originally described by Cox & Hutchinson (1991) based on a partially articulated skull. However, most of its anatomy was still unknown as it is embebed in the rocky matrix. My work published in 2019 with my MSc. advisors Valeria Gallo and Matt Friedman provided a closer look at this unique fish.
Our work provides novel information on skull and shoulder girdle anatomy for this species, which is only known from its type specimen. Previous interpretations of this taxon based on overall morphology of skull dermal bones and teeth proposed a close relationship to acrolepids or birgeriids. However, the new anatomical features uncovered in the micro-CT scan do not support these relationship hypotheses and places Brazilichthys well-within the ray-finned fish stem, crownward of Devonian taxa, far apart from Birgeria that appears within or close to the crown.
The most noticeable aspect of Brazilichthys macrognathus--its long jaws and large teeth--show unique features, but similar jaw anatomy is found in other predatory Paleozoic ray-finned fishes, including Tegeolepis, Cosmoptychius, Rhabdolepis, Nematoptychius, and Pygopterus. Future work on these and other predatory Paleozoic ray-finned fishes might shed light on the relationship of these taxa.
Cox, C. B., and P. Hutchinson. 1991. Fishes and amphibians from the Pedra de Fogo Formation of Northern Brazil. Palaeontology, 34:561–573
Figueroa, R.T., Fridman, M. and Gallo, V. 2019. Cranial anatomy of the predatory actinopterygian Brazilichthys macrognathus from the Permian (Cisuralian) Pedra de Fogo Formation, Parnaíba Basin, Brazil. Journal of Vertebrate Paleontology, 39(3): e1639722. doi: 0.1080/02724634.2019.1639722
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