Tully Monster (Paleocasts) - Dinosaur Toy Blog

The Tully Monster. Tullimonstrum gregarium. What was it? Ever since fossils of this marine predator were first discovered in the Mason Creek formation by amateur collector Francis Tully, paleontologists have been baffled trying to decipher its phylogenetic placement and relationships. It has bounced back and forth between invertebrate and vertebrate and at one time or another has been linked to non-vertebrate chordates, vertebrates, mollusks, and arthropods, among others. Here are some brief bullet points on the history of theories regarding its relationships:

In 1969, it was thought to be the representative of a stem group of any one of several phyla of worms that are poorly represented today
In 2005 and 2011, respectively, similarities were noted between the spiralian Netocaris and the dinocarididan Opabinia, but it was noted other features were too morphologically dissimilar
In 2016, the Tully Monster was considered to be a vertebrate linked to lampreys based on a cartilaginous arcualia, a dorsal fin and asymmetric caudal fin, keratinous teeth, a single nostril, and tectal cartilages
Also in 2016, other researches used eye morphology to suggest a stem-vertebrate affinity
Studies in 2017 suggested the eye stalks tail fins, brain, and proboscis again supported dinocaridian affinities
Studies in 2019 noted similarities to mollusks, and while the authors did not claim Tullimonstrum was a mollusk outright, they could not rule-out invertebrate affinities
Independent studies in 2020 and 2022 suggested that organic material in fossils was suggestive of chordate tissues rather than the chitinous arthropod exoskeleton, again suggesting chordate or vertebrate affinities
In 2023, a study scanning 153 specimens of Tullimonstrum suggested that the 2016 findings linking the animal to vertebrates could not be supported. They suggested the Tully Monster could be either a non-vertebrate chordate or possibly a ‘protostome’

Today we will be looking at a Tully Monster figure from artist Patrick May, who sells his figures under the brand Paleocasts. He used to sell on Etsy but it appears he has shifted more to eBay. Today’s figure, which was originally produced in 2011, is based on the 1969 reconstruction. After I purchased this figure, Patrick and I got chatting and he is going to be displaying an updated model is some upcoming shows. The updated model isn’t available yet but when it does become available, I would like to purchase one! Other than a figure by Medicom, I am not aware of any mass-produced figures of this species. Most are produced by artists such as Patrick and Jetoar (Paleo-Creatures) or museum-quality models such as Trilobiti Design.

The Paleocasts Tully Monster measures 16.5 cm for a scale of 2:1-1:2, so it could fit into the 1:1 range for a medium-sized specimen.

The model is made of urethane resin is permanently affixed to a piece of wood by a support rod (I assume it’s permanent; I haven’t tried to manipulate it for fear of breakage). The TM is sculpted in a gentle pose as if peacefully gliding through the water looking for its next meal.

Because this is an outdated model, it is flatter than current reconstructions and it has lateral tail fins rather than dorsal and ventral fins. The eyes are stalked, but they are attached at the bottom rather than the top of the ‘head’. The mouth at the end of the proboscis is held horizontally when in modern constructions it is held vertically.

The dorsal side is painted an olive-green while the ventral side is largely unpainted. The tips of the eyes are black.

Overall this is a very nice rendition of an earlier concept of T. gregarium. At the time of this writing it is outdated, yes, but this is one of those interesting critters where it is fun to have multiple figures of showing morphological changes as our understanding of the animal changes over time (much like Hallucigenia).

Here it is with a little placard that it came with: