The Jurassic piranha mimic, Dapedium: why even a little reconstruction matters

Finding a fossil is one thing. 
Cleaning the fossil to reveal the specimen in all of its wonder and detail is another thing. Recontructing a tracing of the fossil to its in vivo appearance is the final necessary step. For this specimen of the Early Jurassic deep-bodied fish, Dapedium, the preliminary steps were taken by Smithwick 2015. The final step was added here.

Figure 1. The skull of Dapedium (Early Jurassic) from Smithwick 2015, plus original tracing plus DGS colors and colors restored to in vivo positions.

Figure 1. The skull of Dapedium (Early Jurassic) from Smithwick 2015, plus original tracing plus modified tracing to match photo, plus DGS colors plus colors restored to in vivo positions. Note the several bones that are homologs to the squamosal (magenta) and jugal (cyan) in tetrapods.

Earlier Dapedium was added
to the large reptile tree (LRT, 1654+ taxa), but this skull provides more data in the form of this higher resolution image.

Figure 3. Dapedium with skull bones colorized and reconstructed using DGS methods.

Figure 2. Dapedium with skull bones colorized and reconstructed using DGS methods.

Dapedium granulatus, D. caelatum (Leach 1822; Thies and Hauff 2011; Lower Jurassic; UHH 2) nests between Lepisodetes and the extant gar, Lepisosteus, in the LRT. This piranha-mimic has a deep skull and small strong jaws. The tail is just barely heterocercal (Fig. 2).


References
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.
Smithwick F 2015. Feeding ecology of the deep-bodied fish Dapedium (Actinopterygii, Neopterygii) from the Lower Lias (Sinemurian) of Dorset, England. Palaeontology 58(2):293–311.

wiki/Dapedium

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