Cryptid Corner #6: Zuiyo-Maru Carcass

We’re six issues in and now we are out at sea and we have a real corpse of an issue. Marine cryptids are that much more mysterious than terrestrial ones. Let’s splash down at the bottom of the world and the bottom of the ocean with a prehistoric cryptid.

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#6 – The Zuiyo-Maru Carcass

Description

The Zuiyo-Maru carcass was the remains of a marine creature that was approximately 10m long and weighed 1.8 tons. The entirety of the creature’s remains was not found, but consisted of a head atop on elongated neck, with four large red coloured flippers and a tail. The neck was approximately 1.5m long, while the tail was 2m long, and had the remains of a dorsal fin present (1). No internal organs of the creature remained, with only flesh and fats remaining, with no signs of a skeleton present. The status of the carcass was degraded and was foul smelling, and it should be noted that the remains do not constitute the entire creature.

Folklore and Evidence (or lack of…)

The carcass was captured by the Zuiyo-Maru, a Japanese owned trawler, on the 25^th of April of 1977, who pulled the body up in a net alongside a regular catch of fish. The Zuiyo-Maru was fishing off the coast of New Zealand and was considered to be an unknown animal by the crew of the ship (2). Sketches and photographs of the carcass were taken, with the creature being named as Nyu Nesshii, which translates as ‘New Nessie’ by the crew. Samples of the skeleton, fins and skin were taken by the crew before the captain, Akira Tanaka, ordered the body to be dumped back into the ocean. When asked Tanaka stated that he made the decision because he feared that holding the carcass would spoil the catch of fish that the Zuiyo-Maru has already brought aboard.

On returning to Japan, the photos and samples were donated to Yokohama National University for analysis. The university asked for Captain Tanaka and the crew of the Zuiyo-Maru but were unable to relocate the carcass. While I don’t want to ruin the next section of this issue to much, the results of the initial testing and the photographs sparked a ‘plesiosaur craze’ in Japan, due to the proposed identity of the animal that the carcass had come from.

Well, what is it?

The initial studies of the Zuiyo-Maru Carcass by Professor Tokio Shikama and Dr Fujiro from Yokohama National University excitedly proclaimed that the remains were from a plesiosaur, an extinct group of marine reptiles that went extinct 66 million years ago (mya). At first glance there is a similarity between the carcass and the skeletal remains of plesiosaurs, however there are morphological reasons that preclude the identity of the corpse as one of these extinct reptiles. While the neck looks elongated, the length of the tail is far longer, while the tails of both plesiosaurs and pliosaurs have short tails in comparison to their necks. Initially described as having four flippers, further studies of the photos reveal that two of the flippers are actually dorsal fins, and that decay has warped the dimensions of the carcass (3).

When talking about any marine prehistoric based cryptids, the rediscovery of the two extant species of coelacanth (Latimeria chalumnae) and (Latimeria menadoensis) are often brought up. Coelacanths, both extant and extinct are two points in a ghost lineage, with a gap of 66 million year between the last fossils and modern species (4), and this is often used to state if a coelacanth species could survive undetected for such a period of time, then so could animals like plesiosaurs. The difference between plesiosaurs and coelacanths is that the former group is typically associated with shallower waters, and would have experienced competition with, and would be prey to, extinct whale genera such as Basilosaurs, Brygmophyseter and Livyatan (5), as well as the mega-tooth sharks such as Megalodon. Even if plesiosaurs could survive these predators, the glacial maximum would make conditions difficult for marine reptiles to survive, and their coastal nature would mean that they would be readily seen by human sailors and fishermen. The reason why coelacanths survived is because the ancestors of the modern species lived-in deep-water environments where conditions change slowly, while the shallow water species went extinct in the Cretaceous-Paleogene (K-Pg) Impact (6). Deep water coelacanths that survived the K-Pg impact likely didn’t fossilise because they live in deep water environments which are hard to find fossils in, due to the hostility of the abyssal biome to human exploration.

So, if a plesiosaur is not the identity of the Zuiyo-Maru Carcass, then what is? Analysis of the oils and fats gathered in the 1970s suggest that the remains are that of a large basking shark (Cetorhinus maximus). Basking sharks are native to the waters around New Zealand, and while typically they only reach an average length of 7.9m (7), specimens reaching over 10m in length have been reliably recorded but are not common (8). The spine and brain case of basking sharks are more calcified than those of other cartilaginous fish and are likely to be among the last of the animal to decay, warping the bodies appearance. Samples taken from the fins reveal cartilaginous fibres that are only found in fish, and are not present in modern tetrapods, and likely in extinct species that would include plesiosaurs.

Bibliography

1. Kuban, Glen J. (May–June 1997). "Sea-monster or Shark? An Analysis of a Supposed Plesiosaur Carcass Netted in 1977" (Reprint). Reports of the National Center for Science Education. 17 (3): 16–28

2. Bord, Janet and Colin (1990), in Varelser från det okända (Det oförklarliga), Bokorama.

3. Yasuda, F. & Taki, Y. (July 1978), "Comparison of the unidentified animal with fishes", Collected Papers on the Carcass, Tokyo: La Societe Franco-Japonaise D’oceanographie, pp. 61–62

4. Toriño, Pablo; Soto, Matías; Perea, Daniel (2021-02-25). "A comprehensive phylogenetic analysis of coelacanth fishes (Sarcopterygii, Actinistia) with comments on the composition of the Mawsoniidae and Latimeriidae: evaluating old and new methodological challenges and constraints". Historical Biology. 33 (12): 3423–3443.

5. Lambert, Olivier; Bianucci, Giovanni; Post, Klaas; de Muizon, Christian; Salas-Gismondi, Rodolfo; Urbina, Mario; Reumer, Jelle (2010). "Corrigendum: the giant bite of a new raptorial sperm whale from the Miocene epoch of Peru". Nature. 466 (1134): 105–108.

6. Schwimmer, D.R.; Stewart, J.D.; Williams, G.D. (1994). "Giant fossil coelacanths of the Late Cretaceous in the eastern United States". Geology. 2 (6): 503–506

7. Hernández, Sebastián; Vögler, Rodolfo; Bustamante, Carlos; Lamilla, Julio (2010). "Review of the occurrence and distribution of the basking shark (Cetorhinus maximus) in Chilean waters". Marine Biodiversity Records. 3: e67

8. Pauly, D. (2002). Growth and Mortality of the Basking Shark Cetorhinus maximus and their Implications for Management of Whale Sharks Rhincodon typus. Vol. Elasmobranch biodiversity, conservation, and management : proceedings of the international seminar and workshop, Sabah, Malaysia, July 1997. Fowler, Sarah L., Reed, Tim M., Dipper, Frances, 1951-, IUCN--The World Conservation Union. Species Survival Commission. Gland, Switzerland: IUCN.

Picture Credits

1. Zuiyo_Maru.jpg (510×328) (genesispark.com)

2. Plesiosaur-Skeleton.png (1115×670) (inspiringtravelscotland.com)

3. R.32d48c8bef50151437d9939113973682 (1760×880) (bing.com)

4. R.0859415956cb94cde27241af0a920d9d (1200×675) (bing.com)

@cbishop, @ghostodoofus2, @jacdec @whathappened and @arctika

We're in deep now...

Also could someone spin the wheel of cryptids embedded below so we can figure out what the next issue is about!

Wheel of Cryptids

@sundown89:

Mapinguari

@jacdec: Cool back to the Americas I guess.

@sundown89: Yes. South America as I could read. It's a myth I don't know a bout.

@jacdec: Brazil I believe, but I may be misremembering.

Cryptic cryptid bump. :)