Experimental Biomechanics on Trinucleid Fringe Pits (trilobita)

Kirk Pearson, Oberlin CollegeFollow

Location

King Building 343

Document Type

Presentation

Start Date

4-28-2017 3:00 PM

End Date

4-28-2017 4:20 PM

Abstract

The morphometric uniqueness of the trinucleid family of fossil arthropods, known as the trilobites, has led to a considerable amount of attention in paleontology literature. In particular, the distinctive hourglass-shaped pits that dot their anterior have been the subject of debate for over a century. Though anatomically well understood, their function remains unknown. Many proposals have been suggested, including its use as a sieve for filter feeding, a strong shield for defense, and a sensory mechanism. Despite the wide ranges of speculations, no study has attempted to model these hypotheses with experimental methods. This study in functional morphology attempts to shed light on the validity of the most contentious of these theories by 3D printing a trinucleid head and testing its abilities in a variety of situations. We found that the dominant theories for over a century, filter feeding and strengthening, are not well supported. Instead, our results suggest that the pits are an ontogenetic signature that allow the cephalon to grow larger, providing trinucleids with an excellent mechanism for plowing through fine-grained silts and clays.

Keywords:

paleontology, biophysics, physical modeling, sedimentology, evolutionary biology

Notes

Session II, Panel 10 - Natural | Resilience
Moderator: Keith Tarvin, Chair and Professor of Biology

Full text thesis available here.

Major

Geology; Composition; Cinema Studies

Advisor(s)

Karla Hubbard, Geology

Project Mentor(s)

Karla Hubbard, Geology
Dennis Hubbard, Geology
Steven Wojtal, Geology
Yolanda Cruz, Biology

April 2017

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Apr 28th, 3:00 PM Apr 28th, 4:20 PM

Experimental Biomechanics on Trinucleid Fringe Pits (trilobita)

King Building 343

The morphometric uniqueness of the trinucleid family of fossil arthropods, known as the trilobites, has led to a considerable amount of attention in paleontology literature. In particular, the distinctive hourglass-shaped pits that dot their anterior have been the subject of debate for over a century. Though anatomically well understood, their function remains unknown. Many proposals have been suggested, including its use as a sieve for filter feeding, a strong shield for defense, and a sensory mechanism. Despite the wide ranges of speculations, no study has attempted to model these hypotheses with experimental methods. This study in functional morphology attempts to shed light on the validity of the most contentious of these theories by 3D printing a trinucleid head and testing its abilities in a variety of situations. We found that the dominant theories for over a century, filter feeding and strengthening, are not well supported. Instead, our results suggest that the pits are an ontogenetic signature that allow the cephalon to grow larger, providing trinucleids with an excellent mechanism for plowing through fine-grained silts and clays.