https://theconversation.com/the-mysterio...ous-126531
EXCERPT: . . . Every now and again, scientists discover fossils that are so bizarre they defy classification, their body plans unlike any other living animals or plants. Tullimonstrum (also known as the Tully Monster), a 300m-year-old fossil discovered in the Mazon Creek fossil beds in Illinois, US, is one such creature.
At first glance, Tully looks superficially slug-like. But where you would expect its mouth to be, the creature has a long thin appendage ending in what looks like a pair of grasping claws. Then there are its eyes, which protrude outward from its body on stalks. Tully is so strange that scientists have even been unable to agree on whether it is a vertebrate (with a backbone, like mammals, birds, reptiles and fish) or an invertebrate (without a backbone, like insects, crustaceans, octopuses and all other animals).
[...] The body plan of the Tully Monster is so unusual in it’s entirety that it will greatly expand the diversity of of whatever group it ultimately belongs to, changing the way we think about that group of animals. ... 2016 research argued the animal should be grouped with vertebrates because its eyes contain pigment granules called melanosomes, which are arranged by shape and size in the same way as those in vertebrate eyes.
But our research shows that the eyes of some invertebrates such as octopus and squid also contain melanosomes partitioned by shape and size in a similar way to Tully’s eyes, and that these can also be preserved in fossils... (MORE - details)
https://www.youtube-nocookie.com/embed/frnio8eSFyk
EXCERPT: . . . Every now and again, scientists discover fossils that are so bizarre they defy classification, their body plans unlike any other living animals or plants. Tullimonstrum (also known as the Tully Monster), a 300m-year-old fossil discovered in the Mazon Creek fossil beds in Illinois, US, is one such creature.
At first glance, Tully looks superficially slug-like. But where you would expect its mouth to be, the creature has a long thin appendage ending in what looks like a pair of grasping claws. Then there are its eyes, which protrude outward from its body on stalks. Tully is so strange that scientists have even been unable to agree on whether it is a vertebrate (with a backbone, like mammals, birds, reptiles and fish) or an invertebrate (without a backbone, like insects, crustaceans, octopuses and all other animals).
[...] The body plan of the Tully Monster is so unusual in it’s entirety that it will greatly expand the diversity of of whatever group it ultimately belongs to, changing the way we think about that group of animals. ... 2016 research argued the animal should be grouped with vertebrates because its eyes contain pigment granules called melanosomes, which are arranged by shape and size in the same way as those in vertebrate eyes.
But our research shows that the eyes of some invertebrates such as octopus and squid also contain melanosomes partitioned by shape and size in a similar way to Tully’s eyes, and that these can also be preserved in fossils... (MORE - details)