Tetronarce (Torpedo) aand Palaeospondylus

Tetronarce fairchildi (originally Torpedo fairchildi Hutton 1872, 1m) is the extant New Zealand torpedo, an electric 'ray' on the outside. Here it nests with Sphyrna, the hammerhead shark, based on its skeleton. So this 'ray' is convergent with other rays. Note the broad nasals with open medial architecture, underslung jaws with tiny, single-cusp teeth and shark-like tail. Here the eyeball stalks are preserved, distinct from most other tetrapods tested in the LRT, probably due to careful dissection to get at its cartilaginous skeleton.

Palaeospondylus gunni(Traquair 1890, Hirasawa et al. 2016, 2022; Joss and Johanson 2007, Johanson et al. 2017, Thomson 2004; Middle Devonian) was an enigma until nested in the LRT where it nests with the New Zealand torpedo, Tetronarce. Perhaps only juvenile specimens are known.

Hirasawa T, Oisi Y and Kuratani S 2016. Palaeospondylus as a primitive hagfish. Zoological Letters. 2 (1): 20.

Hirasawa T, Hu Y, Uesugi, K. et al. 2022. Morphology of Palaeospondylus shows affinity to tetrapod ancestors. Nature https://doi.org/10.1038/s41586-022-04781-3

Hutton FW 1872. Catalogue with diagnoses of the species. Ed. Hutton, FW and Hector J (eds), Fishes of New Zealand, pp. 1-88 pls 1-12, Colonial Museum and Geological Survey Department, Wellington.

Joss J and Johanson Z 2007. Is Palaeospondylus gunni a fossil larval lungfish? Insights from Neoceratodus forsteri development. J Exp Zool B Mol Dev Evol. 2007 Mar 15;308(2):163-71. https://pubmed.ncbi.nlm.nih.gov/17068776/

Johanson Z et al. 5 co-authors 2017. Questioning hagfish affinities of the enigmatic Devonian vertebrate Palaeospondylus. Royal Society Open Science. 4 (7): 170214.

Smith A 1829. Descriptions of new, or imperfectly known objects of the animal kingdom, found in the south of Africa. South African Commercial Advertiser 3: 2.

Thomson KS 2004. A Palaeontological Puzzle Solved?. American Scientist. 92 (3): 209–211.

Thomson KS, Sutton M and Thomas B 2004. A larval Devonian lungfish. Nature 426(6968):833-834.

Traquair RH 1890. On the fossil fishes at Achanarras Quarry, Caithness. Ann Mag
Nat Hist 6th Ser. 1890;6:479–86.

wiki/Torpedo_fairchildi
wiki/Palaeospondylus

Chondrichthyes

Ozarcus

Squalus

Rhinopristiformes

Rhinobatos