Tullimonstrum gregarium -- A Longstanding Mystery Has a Possible Solution

[Recusant]

A team of scientists has presented evidence that they say allows them to finally correctly classify one of the more bizarre animals from the Late Carboniferous.

"What Is a Tully Monster? Scientists Finally Think They Know" | Smithsonian

An artist's rendering shows what a Tully Monster might have looked like
300 million years ago.
Image Credit: Sean McMahon

The worm-like creatures writhed in the dark waters, fins twitching and eyestalks roving. Each one sported a long, pincher-tipped proboscis lined with tiny, needle-like teeth. When paleontologists found fossils of these ancient horrors trapped in stone, they named them Tullimonstrum gregarium, or Tully monsters.

For roughly 60 years, no one could say for sure what the strange beasts actually were. Paleontologist Eugene Richardson, who gave the species its name in 1966, was so unsure of the creature's nature that he wasn't confident sticking it within any known lineage beyond "animal."

Now, an international team says they have at last cracked the mystery, and their answer overturns every other theory offered to date. Depending on who you asked, the Tully Monster could have been related to ribbon worms, snails, eel-like protovertebrates called conodonts or other ancient oddballs, like another nozzle-nosed creature called Opabinia. But based on studies of more than 1,200 fossil specimens, the researchers say the Tully Monster was really a vertebrate, specifically, a type of fish akin to modern lampreys. If they're right, the fossil changes what we know about the history of these aquatic bloodsuckers.

[Continues . . .]

The abstract from the paper on the Nature website:

Problematic fossils, extinct taxa of enigmatic morphology that cannot be assigned to a known major group, were once a major issue in palaeontology. A long-favoured solution to the 'problem of the problematica', particularly the 'weird wonders' of the Cambrian Burgess Shale, was to consider them representatives of extinct phyla. A combination of new evidence and modern approaches to phylogenetic analysis has now resolved the affinities of most of these forms. Perhaps the most notable exception is Tullimonstrum gregarium, popularly known as the Tully monster, a large soft-bodied organism from the late Carboniferous Mazon Creek biota (approximately 309–307 million years ago) of Illinois, USA, which was designated the official state fossil of Illinois in 1989. Its phylogenetic position has remained uncertain and it has been compared with nemerteans, polychaetes, gastropods, conodonts, and the stem arthropod Opabinia. Here we review the morphology of Tullimonstrum based on an analysis of more than 1,200 specimens. We find that the anterior proboscis ends in a buccal apparatus containing teeth, the eyes project laterally on a long rigid bar, and the elongate segmented body bears a caudal fin with dorsal and ventral lobes. We describe new evidence for a notochord, cartilaginous arcualia, gill pouches, articulations within the proboscis, and multiple tooth rows adjacent to the mouth. This combination of characters, supported by phylogenetic analysis, identifies Tullimonstrum as a vertebrate, and places it on the stem lineage to lampreys (Petromyzontida). In addition to increasing the known morphological disparity of extinct lampreys, a chordate affinity for T. gregarium resolves the nature of a soft-bodied fossil which has been debated for more than 50 years.

[xSilverPhinx]

What a bizarre looking creature. I like it. 

[Recusant]

What a bizarre looking creature. I like it.

I like them too. Like something a particularly imaginative science fiction author might come up with as part of the fauna of a strange planet.

[joeactor]

weird and interesting...

Thanks, Rec!

[Biggus Dickus]

Yes a very interesting article, and how clever to finally deduce the Tully's nature from their "Gut Content". -thanks for sharing.


To me they remind me of either a fishing lure or the latest steam vacuum from Dyson. (I have a lure somewhere, yellow similar shape that I used as a boy fishing with my Grandpa)

[Ecurb Noselrub]

The 5 little holes on its side line up like port holes.  I think it was an ancient cruise ship.

[chimp3]

it is amazing . The possible life forms that did not survive. Imagine if we reset the dial and life had to evolve again. Sci-fi is no stranger than truth.