104 D22. Paleontology: Recent Developments in Phylogeny, Morphological Patterns, and Biogeography

Monday, 10 October 2022
1:30 PM - 5:30 PM
Mile High Ballroom 4C

INVESTIGATING THE HYDRODYNAMICS OF THE ENIGMATIC CARBONIFEROUS FISH, TULLIMONSTRUM GREGARIUM, WITH COMPUTATIONAL FLUID DYNAMICS (CFD)

Paper number: 104-2
Program: Technical Sessions
Time: 1:45 PM – 2:00 PM

Authors

Abstract

Tullimonstrum gregarium, more commonly known as the Tully Monster, is one of the strangest creatures in the fossil record. While it was traditionally considered a problematic fossil, recent studies have firmly identified the Tully Monster as a vertebrate, tentatively as a relative of lamprey and hagfish. This may offer some insight into the Tully Monster’s ecology, but the Tully Monster’s swimming ability remains uncertain due to its strange body plan. The Tully Monster’s elongate proboscis and eyebar, for example, are unusual among vertebrates and likely affect the Tully Monster’s swimming abilities. The Tully Monster also lacks paired fins, like pectoral fins and pelvic fins, which typically allow fish to turn and stabilize their bodies. Collectively, these strange characteristics and the Tully Monster’s posteriorly concentrated musculature call the Tully Monster’s swimming mechanisms into question. Furthermore, the proboscis itself could have been held in various positions while the Tully Monster swam, and different proboscis positions would have different effects on the Tully Monster’s swimming. This study aims to investigate the hydrodynamics of these features to gain insight into the Tully Monster’s swimming ability using computational fluid dynamics (CFD). 2D simulations of the Tully Monster revealed that the eyebar and proboscis are likely key hydrodynamic features, and that the tail fin complex could have generated pressure differentials. Pressure differentials generated around the body also suggest the Tully Monster was a slow swimmer, and likely had a hydrodynamic tendency to descend in the water column. The proboscis position during swimming, however, remains uncertain.

Geological Society of America Abstracts with Programs. Vol. 54, No. 6

doi: 10.1130/abs/2022AM-377013

© Copyright 2022 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.