Graduate Program

Environmental Biology

Degree Name

Master of Science (MS)

Semester of Degree Completion

1984

Thesis Director

Edward O. Moll

Abstract

Twelve Genera (spanning three Families) of Malaysian Turtles were studied to determine whether bone lengths could be correlated to mode of locomotion. Ulna, humerus, tibia, femur, coracoid (among others) were measured and results were presented graphically. Five of the genera were observed singly in a large aquarium. Data were recorded on the amount of time each spent in different locomotor modes. Both limb length data and aquarium observations suggest that turtles can be grouped into three main locomotor habits (i.e. terrestrial walking, bottomwalking, and swimming). The terrestrial group includes the genera, Geochelone, Kinixys, and Gopherus. Bottomwalkers include Siebenrockiella, Cyclemys, Notochelys, Cuora, Heosemys, and Orlitia. Highly aquatic turtles include Trionyx, Kachuga, Callagur, Batagur, and Pelochelys. The combined mean lengths of the three groups were then compared. Forelimb measurements (ulna, humerus) were found to be significantly different among each group. Ulna and humeri were found to be shorter in swimmers and longer in terrestrials. Hindlimb measurements (tibia, femur) were found to be indistinguishable for the three groups. These data point towards divergent evolution of forelimb bones while hindlimbs seem to have remained evolutionarily conservative. These results could be easily tested on a similar group of new world turtles.

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