Shonisaurus popularis


Shonisaurus is a large ichthyosaur of the Triassic Period of Nevada.


Shonisaurus grew to around 15 meters in length. Another species found in British Columbia was even larger at 21 meters, but it was later shown to be a specimen of its close relative Shastasaurus.[1]

An early member of the ichthyosaur group, Shonisaurus was relatively slender and had no dorsal fin.[2] The upper fluke was also probably much less developed than that of later examples.[3]


Fossils of Shonisaurus were first found in the Luning Formation of Nevada in the 1920s, but the over 30 partial specimens were not fully uncovered for 30 years. The skeletons all died in the same place and were preserved together. The genus was described by Charles Camp in 1976.[4] It became the state fossil of Nevada in 1984.


Bonebed interpretationEdit

Main article: Triassic kraken

In 2011, two geologists from Mount Holyoke College suggested that the assemblage of Shonisaurus skeletons was placed in the depths of the ocean by an intelligent giant squid they referred to as a "kraken". They suggested that the vertebrae were placed in the shape of the Triassic squid's tentacles to form a work of art. Their hypothesis has been met with mixed reaction.[5][6]



Shonisaurus probably ate fish and other small organisms living in the sea.


  1. Sander, P. Martin; Chen, Xiaohong; Cheng, Long; Wang, Xiaofeng (2011). Claessens, Leon. ed. "Short-Snouted Toothless Ichthyosaur from China Suggests Late Triassic Diversification of Suction Feeding Ichthyosaurs". PLoS ONE 6 (5): e19480. doi:10.1371/journal.pone.0019480. PMC 3100301. PMID 21625429.
  2. Kosch, Bradley F. (1990). "A revision of the skeletal reconstruction of Shonisaurus popularis (Reptilia: Ichthyosauria)". Journal of Vertebrate Paleontology 10 (4): 512. doi:10.1080/02724634.1990.10011833.
  3. Wallace, D.R. (2008). Neptune's Ark: From Ichthyosaurs to Orcas. University of California Press, 282pp.
  4. Camp, CL (1980), Large ichthyosaurs from the Upper Triassic of Nevada. Palaeontographica Ser. A. 170: 139-200.
  5. McMenamin, M.A.S. and Schulte McMenamin, D.L. (2011). "Triassic kraken: the Berlin Ichthyosaur death assemblage interpreted as a giant cephalopod midden." Geological Society of America Abstracts with Programs, 43(5): 310.