Meeting Abstract

P1-95   -   Resurrecting extinct cephalopods with neutrally buoyant, biomimetic robots and 3D motion tracking Peterman, DJ*; Hebdon, N; Ritterbush, KA; University of Utah, Salt Lake City, UT; Chapman University, Orange, CA; University of Utah, Salt Lake City, UT David.Peterman@utah.edu

Among marine organisms, externally shelled cephalopods have evolved unique solutions to locomotion and buoyancy management, becoming dominant components of marine ecosystems for much of the current eon. Today, cephalopods are the most complex and mobile group of mollusks, yet the swimming capabilities and life habits of extinct morphologies are poorly understood. The shapes of their rigid shells govern how these animals would have managed buoyancy and the distribution of their organismal mass (influencing stability, orientation, and the transmission of thrust into movement). Additionally, the external shape of the shell affects hydrodynamics (e.g., drag, speed, acceleration), and therefore the efficiency and cost of moving through daily life. Hydrostatic simulations of theoretical morphologies across the planispiral morphospace reveal that the majority of planispiral cephalopods are much less stable than extant Nautilus – a commonly used analogue for extinct shelled cephalopods. The differences in external shell shape and hydrostatic stability were investigated with self-propelling robots, weighted to impart the proper mass distribution inferred by the virtual models. Each morphotype faces implicit advantages and disadvantages in both hydrostatics and hydrodynamics, which would have constrained the modes of life for these ubiquitous, ecologically significant animals. The “performances” of these cephalopods can provide critical context to the dynamics of their evolution and extinction through a biomechanical framework.