ABOUT MEI study how functional morphology shapes evolutionary patterns. I essentially “resurrect” animals from fossils using computer models and simulations, robotics, 3D printing, and other emerging technologies. These approaches allow me to explore organisms that offer unique views into aquatic locomotion over vast evolutionary timescales. My research is driven by investigating: 1) how organisms interact with the physics of their environments, 2) the ecological and evolutionary roles of these functional constraints, and 3) how unique biological experiments can inform on current technologies.
While I am interested in the function, diversity, and paleoecology of marine animals more broadly, I largely focus on externally shelled cephalopods (e.g., ammonoids and nautiloids). These animals are excellent targets to study in the framework of evolutionary biomechanics due to their ecological significance, ubiquity, and high evolutionary rates. With these animals, I can answer broad ecological questions, including: how was morphology related to particular modes of life?, what ecological roles suited these animals?, and how did these roles change throughout the Phanerozoic? Current position: Postdoctoral scholar at Penn State University working with Dr. Margaret Byron in the Environmental and Biological Fluid Mechanics Laboratory. |
David Peterman with a reconstructed ammonite (Paracoroniceras lyra). This model was constructed with 3D computer modeling, 3D printed, then airbrushed. These fossil reconstructions have been used extensively for science outreach/teaching, and have ended up in museums and collections across the globe. |
Recent ProjectsVirtual and physical reconstructions:
Developing new techniques to virtually reconstruct animals from fossil remains offers unprecedented views into past ecosystems. Digital reconstructions can inform on hydromechanical properties that constrained the life habits of these animals. Neutrally buoyant, weighted, 3D prints, allow hydrodynamic analyses in complex, real world settings. Heteromorph ammonoids: Non-planispiral ammonoids were major components of marine ecosystems and iteratively evolved during the Mesozoic. Historically, they have been thought of as "maladapted" or inferior due to their unusual shapes. However, my recent work demonstrates these animals had unique hydrostatic properties that may have conferred selective advantages. Paleobiology + robotics: I use neutrally buoyant, self-propelling, biomimetic robots to explore hydrodynamic advantages and consequences of extinct morphologies. Analysis of their kinematics with 3D motion tracking can provide critical context to the performance of disparate morphologies over evolutionary timescales. Furthermore, my approaches emphasize the coupling of hydrostatics (mass distribution) and hydrodynamics. These properties place severe constraints on swimming capabilities, but are often investigated separately or simplified. Soft robotics and bio-fluid interaction: Using magnetic silicone elastomers, I am exploring the dynamics of how metachronal motion drives fluid flow. This project is inspired by the biomechanics of ctenophores (comb jellies), and aligns with other research in the Environmental and Biological Fluid Mechanics Lab at Penn State. 
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Top left - hydrostatic model of Nipponites mirabilis (after Peterman et al., 2020, PLOS ONE). Top right - hydrostatic model and 3D printed reconstruction of Audouliceras renauxianum (after Peterman et al., 2020, JMS). Middle left - transparent view of an ammonoid robot (Peterman and Ritterbush, 2022; Scientific Reports). Bottom - theoretical ammonoid conchs (Peterman and Ritterbush, 2022; Scientific Reports).
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Above: 3D motion tracking on a neutrally buoyant, self-propelling ammonoid robot to study hydrodynamic attributes of various conch morphologies.
Right: Neutrally buoyant 3D-printed model used to the investigate the relationship between hydrodynamic restoration and hydrostatic stability. These models have adjustable, internal counterweights that allow the mass distribution of the living animal to be imparted in a physical model of differing density and internal shape. |
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Above: Feeding maneuver of the ctenophore Pleurobrachia bachei. Spinning maneuvers enable the prey-covered tentacles to reach the mouth. Eight rows of metachronally beating propulsors (ctene rows) allow near-omnidirectional maneuverability.
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Above: Free-swimming, ctenophore-inspired robot. Magnetoactive propulsors are beating with 20% phase lag at 10 Hz. A single motor actuates 80 propulsors by rotating a spiral, magnetic drive-shaft (note: playback speed = 4X real speed).
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