Author ORCID Identifier

http://orcid.org/0000-0002-4413-1091

Degree Year

2017

Document Type

Thesis

Degree Name

Bachelor of Arts

Department

Geology

Advisor(s)

Karla Parsons-Hubbard
Yolanda P. Cruz

Committee Member(s)

Amanda Henck Schmidt, Chair
Dennis Hubbard
Steven F. Wojtal

Keywords

Trilobites, Functional morphology, CT scanning, 3D printing, Modeling

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 to compensate for their blindness. Despite the wide range of speculations, no study has attempted to model these hypotheses experimentally. Flume experiments and mechanical strength tests using a tenfold scale, 3D-printed model of a trinucleid head suggest that the dominant theories for over a century, filter-feeding and skeletal strengthening, are not well supported. It is proposed that the results suggest that the pits are an ontogenetic signature that optimize the cephalon’s growth to be maximal, providing trinucleids with an excellent mechanism for plowing through fine-grained silts and clays.

Included in

Geology Commons

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