DAO 120:179-187 (2016)  -  DOI: https://doi.org/10.3354/dao03026

Vertebral column anomalies in Indo-Pacific and Atlantic humpback dolphins Sousa spp.

Caroline R. Weir1,2,*, John Y. Wang3,4 

1Ketos Ecology, 4 Compton Road, Kingsbridge, Devon TQ7 2BP, UK
2Department of Zoology, School of Biological Sciences, University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, UK
3CetAsia Research Group, 310-7250 Yonge Street, Thornhill, Ontario L4J 7X1, Canada
4Department of Biology, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada
*Corresponding author:

ABSTRACT: Conspicuous vertebral column abnormalities in humpback dolphins (genus Sousa) were documented for the first time during 3 photo-identification field studies of small populations in Taiwan, Senegal and Angola. Seven Taiwanese humpback dolphins S. chinensis taiwanensis with vertebral column anomalies (lordosis, kyphosis or scoliosis) were identified, along with 2 possible cases of vertebral osteomyelitis. There was evidence from several individuals photographed over consecutive years that the anomalies became more pronounced with age. Three Atlantic humpback dolphins S. teuszii were observed with axial deviations of the vertebral column (lordosis and kyphosis). Another possible case was identified in a calf, and 2 further animals were photographed with dorsal indents potentially indicative of anomalies. Vertebral column anomalies of humpback dolphins were predominantly evident in the lumbo-caudal region, but one Atlantic humpback dolphin had an anomaly in the cervico-thoracic region. Lordosis and kyphosis occurred simultaneously in several individuals. Apart from the described anomalies, all dolphins appeared in good health and were not obviously underweight or noticeably compromised in swim speed. This study presents the first descriptions of vertebral column anomalies in the genus Sousa. The causative factors for the anomalies were unknown in every case and are potentially diverse. Whether these anomalies result in reduced fitness of individuals or populations merits attention, as both the Taiwanese and Atlantic humpback dolphin are species of high conservation concern.


KEY WORDS: Deformities · Lordosis · Kyphosis · Scoliosis · Sousa chinensis · Sousa teuszii


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Cite this article as: Weir CR, Wang JY (2016) Vertebral column anomalies in Indo-Pacific and Atlantic humpback dolphins Sousa spp.. Dis Aquat Org 120:179-187. https://doi.org/10.3354/dao03026

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