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PLESIOSAURUS SNAGGED IN JAPANESE FISHING NETS!

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Author Topic: PLESIOSAURUS SNAGGED IN JAPANESE FISHING NETS!  (Read 3021 times)
In the Mouth of Madness
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« Reply #15 on: October 15, 2011, 03:52:04 pm »

Anatomy

-- The carcass sketch showed six neck vertebrae, viewed as "seven or so" by Obata and Tomoda (1978), which is reasonably consistent with Yano's measurements of neck length (150 cm) and individual vertebra diameter (20 cm). It is also consistent with sharks. However, 6 to 7 cervical vertebrae is not consistent with plesiosaurs and other marine reptiles. Even the pliosaurs, also known as "short-necked" plesiosaurs, have at least 13 neck vertebrae; the "long necked" plesiosaurs have far more. (Obata and Tomoda, 1978, p 46).

-- The head of the creature was reported to be turtle-like (Obata and Tomoda, 1978, p 48). This is consistent with the known cranial remains of a basking shark, which have been specifically described as resembling a turtle head (Omura, Mochizuki, and Kamiya 1978, p 59). In contrast, plesiosaurs had more triangular shaped heads that were not particularly turtle-like (Hasegawa and Uyeno 1978, p 64).

-- Photographs and witnesses confirm the presence of fin rays, which are possessed by most fish, including sharks. In contrast, plesiosaurs had bony phalanges as flipper supports, which were not seen in the carcass (Obata and Tomoda 1978, p 51). The limb bones shown in Yano's drawing were evidently based on presumption or pro-plesiosaur bias rather than observation (Omura and others 1978, p 56; Obata and Tomoda 1978, p 49).

-- One of the photos (Figure 1c) shows an apparent dorsal fin, as illustrated in Figures 5). Dorsal fins are possessed by most fish including sharks, but are thought to have been lacking in plesiosaurs.

-- The V-shaped along the vertebral column (Figure 1c and 5), and near the pectoral girdle (Figure 1a) were identified as myocommata by Omura, Mochizuki, and Kamiya 1978, p 56-57). Myocommata are composed of strong connective tissues between myomeres, and are found in sharks but not reptiles.

-- The ribs were measured as 40 cm (about 16 inches) long, which is far too short for plesiosaurs or other marine vertebrates except sharks (Hasegawa and Uyeno, p 65). Ironically, some have asked whether the ribs might be too long for a shark, which typically have very small ribs. But this was an exceptionally large specimen, and was probably even larger before decomposition. Also, it is not certain that Yano accurately identified or measured the ribs, which do not appear in the photos. Perhaps he mistakenly measured remnant gill arches, myocommata, or muscle furrows, under the assumption that they corresponded to ribs.
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