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batworker — Yamatocetus
#copepteryx #yamatocetus #eomysticetid #baleenwhale #cenozoic #cetacean #crocodile #dugong #inkdrawing #japan #marinemammal #oligocene
Published: 2019-12-18 00:25:25 +0000 UTC; Views: 2095; Favourites: 90; Downloads: 0
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Description
Late Oligocene of Kyushu Island. Pair of the primitive baleen whales, Yamatocetus canaliculatus, came into the river mouth. Some other animals from the same fauna can be seen: unidentified crocodile (bottom left), unidentified dugong (left backround) and giant flightless Suliform birds Copepteryx.PS I made a revised version: www.deviantart.com/batworker/a…
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Comments: 12
Yes. Its uncommon for modern baleen whales, but it was suggested recently, that Eomysticetids had low melon-like structure.
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Cool! So... echolocation might be ancestral to the split between modern mysticetes and odontocetes?
Could you please give me the reference of the paper where they bring evidences of that?
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After your words, I thought and once again looked at various reconstructions. Because it is extremely doubtful - the ancestors of baleen whales should not have echolocation. Apparently, what looks like a “melon” is soft tissue and muscle, conditioned by the shape of the skull, and in a different genus. So I need to make a revised version and return Yamatocetus flat top of the head.
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Definitely the new restoration looks more "mysticetid", but this one is interesting anyway and made us think a little bit. Other thing I have noticed from this conversation is that all modern cetaceans with melons seems to have the melon *before* the blowhole, even sperm whales.
For what genus is that potential "melon-like" soft tissue structure mentioned?
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For Tokarahia.
I would not even say “in front of”, but maybe “around”. But certainly not "behind." In sperm whales, the outer nostril is shifted forward (as I understand it, passing around the spermaceti sac), but the inner nostrils are still on the crown, so everything seems to be in order.
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You mean "Kyushu"? "Kushu" is a fishing port in northern Honshu
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Okazaki, Y. (2012). "A new mysticete from the upper Oligocene Ashiya Group, Kyushu, Japan and its significance to mysticete evolution"
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