A size chart comparing Chased by Sea Monsters’ “Cameroceras” with the largest verified Endoceras. The upper silhouette is redrawn from Marven & James (2004), while the lower silhouette is my own work (from this post).
The “giant orthocone” was a memorable star of the 2003 television miniseries Chased by Sea Monsters (James, 2003).1 Orthocone is a term for any cephalopod with a straight shell and can refer to endoceratoids, orthoceratoids, or baculitid ammonoids (Peterman et al., 2019a; b). The companion book specified that it was intended to be the endocerid Cameroceras (Marven & James, 2004). The book also stated that it had a shell 9-10 meters (29.5-32.8 feet) long. However, that is far longer than the largest confirmed endocerid, Endoceras giganteum, with an estimated shell length of 5.73 meters (18.8 feet; Klug et al., 2015).2 This discrepancy was probably caused by both a dubious specimen and a taxonomic mixup.
Flower (1955) said that he heard about an endocerid shell 30 feet (9.1 meters) long from a New York quarry that was destroyed. If it actually existed, it was most likely an exaggerated E. giganteum since that species is closest in size and also found in that area. Although not explicitly credited, this report presumably inspired the giant orthocone in Chased by Sea Monsters. The book does say that the segment featuring it is set in New York at least. Endoceras has been considered a possible synonym of Cameroceras by some authors (see discussions in Flower, 1955 and Frey, 1995), so the book seems to have followed that opinion. Hence, an oversized endocerid/Endoceras became an oversized Cameroceras and the rest is history.
Notes
1It also made a cameo in the followup series Walking with Monsters (Leland, 2005).
2When it was originally described by Teichert & Kummel (1960), they inaccurately estimated its shell length as 8.15 meters (26.7 feet). This made Flower’s story appear more plausible at the time.
References
- Flower, R.H. (1955). Status of endoceroid classification. Journal of Paleontology, 29(3), 329-371.
- Frey, R.C. (1995). Middle and Upper Ordovician nautiloid cephalopods of the Cincinnati Arch region of Kentucky, Indiana, and Ohio. U.S. Geological Survey Professional Paper, 1066-P, 1-126. https://doi.org/10.3133/pp1066P
- James, J. (Director). (2003, November 9). Dangerous seas (Episode 1) [TV miniseries episode]. In A. Kemp & T. Haines (Executive Producers), Chased by sea monsters. Impossible Pictures.
- Klug, C., De Baets, K., Kröger, B., Bell, M.A., Korn, D., & Payne, J.L. (2015). Normal giants? Temporal and latitudinal shifts of Palaeozoic marine invertebrate gigantism and global change. Lethaia, 48(2), 267-288. https://doi.org/10.1111/let.12104
- Leland, C. (Director). (2005, November 5). Water dwellers (Episode 1) [TV miniseries episode]. In T. Haines (Executive Producer), Walking with monsters. Impossible Pictures.
- Marven, N., & James, J. (2004). Chased by sea monsters: Prehistoric predators of the deep. Dorling Kindersley.
- Peterman, D.J., Barton, C.C., & Yacobucci, M.M. (2019a). The hydrostatics of Paleozoic ectocochleate cephalopods (Nautiloidea and Endoceratoidea) with implications for modes of life and early colonization of the pelagic zone. Palaeontologia Electronica, 22(2), Article 24. https://doi.org/10.26879/884
- Peterman, D.J., Ciampaglio, C.N., Shell, R.C., & Yacobucci, M.M. (2019b). Mode of life and hydrostatic stability of orthoconic ectocochleate cephalopods: Hydrodynamic analyses of restoring moments from 3D printed, neutrally buoyant models. Acta Palaeontologica Polonica, 64(3), 441-460. https://doi.org/10.4202/app.00595.2019
- Teichert, C., & Kummel, B. (1960). Size of endoceroid cephalopods. Breviora, 128, 1-7.
Incertae Sedis 