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Skull morphology of bottlenose dolphins from different ocean populations with emphasis on South America |
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| Authors: | Leandro S L Hohl Fernando L Sicuro Janaína C Wickert Ignacio B Moreno Oscar Rocha-Barbosa André S Barreto |
| Institution: | 1. Departamento de Zoologia, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Laboratório de Zoologia de Vertebrados—Tetrapoda (LAZOVERTE), Rio de Janeiro, RJ, Brazil
Departamento de Ecologia, Instituto de Biologia Roberto Alcantara Gomes Universidade do Estado do Rio de Janeiro, Programa de Pós-Graduação em Ecologia e Evolução, Rio de Janeiro, RJ, Brazil;2. Departamento de Ciências Fisiológicas, Universidade do Estado do Rio de Janeiro, Laboratório de Pesquisas Clínicas e Experimentais em Biologia Vascular (BIOVASC), Rio de Janeiro, RJ, Brazil Contribution: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Supervision, Validation, Visualization;3. Grupo de Estudos de Mamíferos Aquáticos do Rio Grande do Sul, Rua Bento Gonçalves, Torres, RS, Brazil Centro de Estudos Costeiros, Limnológicos e Marinhos (CECLIMAR), Universidade Federal do Rio Grande do Sul, (UFRGS Campus Litoral Norte), Rio Grande do Sul, RS, Brazil Contribution: Data curation, Investigation, Validation, Visualization;4. Centro de Estudos Costeiros, Limnológicos e Marinhos (CECLIMAR), Universidade Federal do Rio Grande do Sul, (UFRGS Campus Litoral Norte), Rio Grande do Sul, RS, Brazil Programa de Pós-Graduação em Biologia Animal (PPGBan), Departamento de Zoologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil Contribution: Conceptualization, Data curation, Investigation, Validation, Visualization, Writing - original draft;5. Departamento de Zoologia, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Laboratório de Zoologia de Vertebrados—Tetrapoda (LAZOVERTE), Rio de Janeiro, RJ, Brazil Departamento de Ecologia, Instituto de Biologia Roberto Alcantara Gomes Universidade do Estado do Rio de Janeiro, Programa de Pós-Graduação em Ecologia e Evolução, Rio de Janeiro, RJ, Brazil Contribution: Conceptualization, Supervision, Validation, Visualization;6. Universidade do Vale do Itajaí, Laboratório de Informática da Biodiversidade e Geomática, Itajaí, SC, Brazil |
| Abstract: | The bottlenose dolphin, genus Tursiops, is cosmopolitan occurring in tropical and temperate regions, with morphological variation between and within different oceans. Since the genus' taxonomy has been under discussion for a long time, this work aimed at analyzing the cranial variability of T. truncatus from different regions of the world. Geometric Morphometrics analyses were performed in 201 skulls of adult specimens, on dorsal, ventral, and lateral views, from the Eastern North Pacific, Eastern North Atlantic, Eastern South Atlantic, and Western South Atlantic oceans. The results indicate differences between individuals that inhabit the Atlantic and Pacific oceans. Within the Atlantic Ocean, there is an evident longitudinal differentiation of specimens from the eastern and western regions. A latitudinal separation was also observed, considering specimens from the North and South Atlantic Ocean. In the Western South Atlantic statistical differences were found between two morphological groups, identified as T. gephyreus (sensu Lahille, 1908) and T. truncatus, and the cross-validation presented 98% as minimum confidence for correct classification of these two groups. The present study provides strong morphological support to consider these two lineages as separate species. |
| Keywords: | biogeography morphological comparison Odontoceti |