Mioplosus labracoides

This was a predatory fish, growing up to 50 cm in length. This specimen nicely shows some of its distinctive anatomical characteristics, such as fusiform body shape, two distinct dorsal fins (the more anterior spiny, and the posterior with segmented rays) and a moderately forked tail fin. According to Grande (2013, p. 161), Mioplosus labracoides is the fish species in Fossil Lake basin with the most specimens fossilized with a partially ingested fish in their throat, including examples of cannibalism. This shows that Mioplosus labracoides was a voracious piscivorous fish that swallowed other fish whole (but see a possible alternative scenario suggested by Robertson et al., 2019), and it also points to unique taphonomic conditions of rapid burial and very limited decay after death.

References

Grande, L., 2013. The lost world of Fossil Lake: Snapshots from deep time. University of Chicago Press. p. 425.

Robertson, D.R., Baldwin, C.C., Bellwood, D., Pyle, R., Smith-Vaniz, W., Tornabene, L. and Van Tassell, J.L., 2019. Aspiration or expiration: hypoxia and the interpretation of fish predation in the fossil record. Palaios, 34(5), pp. 245-247. doi.org/10.2110/palo.2019.027