Anders Galatius

Variation in cranial morphology of bottlenose dolphins (genus Tursiops) off South Africa

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DOI

  • Sibu Ngqulana, Nelson Mandela University
  • ,
  • Pierre Pistorius, Nelson Mandela University
  • ,
  • Anders Galatius
  • Stephanie Plon, Nelson Mandela University
  • ,
  • G. J. Greg Hofmeyer, Port Elizabeth Museum at Bayworld, Nelson Mandela University

Taxonomy plays an important role in conservation biology. Despite the variety of methods used to differentiate units, some groups, such as Delphinidae within the Cetacea have proven difficult to untangle. This study aimed to shed light on morphological variation of the genus Tursiops in South African waters using geometric morphometrics and to distinguish morphological groups and variation in these groups. A total of 241 crania of Tursiops spp. were analyzed using a suite of 2-dimensional landmarks defined on photographs of the specimens. Results revealed two distinct morphological groups, with the smaller cluster comprised mainly of specimens from the cold temperate region off the west coast and the larger cluster comprised of specimens mainly from the warm temperate and subtropical regions off the south and east coast, respectively. We suggest that these groups correspond to different species of Tursiops, but this result requires further support. These groups were treated as separate entities and sexual dimorphism and geographic variation were assessed within each group. While sexual dimorphism and geographic variation were not significant within Cluster D1 and V1, they were significant within Clusters D2 and V2. The few Cluster 1 specimens found in the warm temperate and subtropical regions, relative to the number of Cluster 2 specimens, could be an indication of an offshore distribution for this group in these regions. Alternatively, the smaller cluster may also be indicative of a potentially small population size.

Original languageEnglish
JournalMarine Mammal Science
Volume35
Issue2
Pages (from-to)617-636
Number of pages20
ISSN0824-0469
DOIs
Publication statusPublished - Apr 2019

    Research areas

  • Tursiops spp., bottlenose dolphin, cranial morphology, geometric morphometrics, taxonomy, EXTERNAL MORPHOLOGY, SKULL, Tursiops spp, PORPOISE, COMMON DOLPHIN, DELPHINUS-DELPHIS, TRUNCATUS, GEOGRAPHIC-VARIATION, MORPHOMETRY, POPULATION-STRUCTURE, SEXUAL-DIMORPHISM

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