This thesis studies upper jaw protrusion in carassius auratus (goldfish), a type of Cypriniformes. The presence of a unique sesamoid bone called kinethmoid, suspended by a network of ligaments, allows for more flexibility and longer periods of sustained suction flow speeds in Cypriniformes. Previous researchers used XROMM software to visualize highly accurate (±0.1 mm) re-animations of a carp’s 3D bones in vivo and EMG graphs to visualize muscle activation patterns. Based on those results, this thesis takes a reverse approach by building a working 3D model of a goldfish’s mouth and simulating it using Adams, a multibody dynamics software program. Since all buccal (mouth) parts act in synchrony during each feeding session, this simulation process allows us to vary one parameter at a time and observe how changes in each parameter affect the overall feeding process. Individual bone measurements taken in the lab were translated into a 3D model using Solidworks. The model consisted of five main bones, two maxillary muscles, A1α and A1β; and a network of ligaments that were modelled as linear springs. Four parameters were tested against mouth opening results. They were A1α, A1β, initial kinethmoid position and initial dentary position. The initial position of the dentary was a primary influence in opening the mouth regardless of the amount of A1 maxillary forces applied. At a minimum dentary angle of 49°, the mouth opened for as little as 1 dyne of A1β force. Also, increasing values of A1β as opposed to changing kinethmoid’s starting position had a greater effect on dentary rotation. A1α was the main driver in rotating the kinethmoid while increasing initial kinethmoid position from 130° to 150° increased the total rotational displacement of the kinethmoid by about 45°. All angles are measured counterclockwise to the part’s anteroposterior axis. Both actions led to protruding the premaxilla forward and opening of the mouth. The 5 kinematic patterns were on par with past experimental results, thereby validating the approach taken to creating a realistic 3D model.

Library of Congress Subject Headings

Goldfish--Anatomy--Computer simulation; Jaws--Computer simulation; Three-dimensional modeling

Publication Date


Document Type


Student Type


Degree Name

Mechanical Engineering (MS)

Department, Program, or Center

Mechanical Engineering (KGCOE)


Steven Day

Advisor/Committee Member

Agamemnon Crassidis

Advisor/Committee Member

L. Patricia Hernandez


Physical copy available from RIT's Wallace Library at QL638.C94 T74 2016


RIT – Main Campus

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