A contribution to the anatomy of two rare cetacean species: The hourglass dolphin ( <i>Cephalorhynchus cruciger</i> ) and the spectacled porpoise ( <i>Phocoena dioptrica</i> )
The anatomical description of the hourglass dolphin (Cephalorhynchus cruciger) and the spectacled porpoise (Phocoena dioptrica) remains largely unexplored, due to limited specimen availability and preservation challenges. This study employed digital imaging techniques, conventional histology, and computed tomography to provide visualization of anatomical structures for a detailed analysis. We present a comprehensive analysis of the gross macroscopical and microscopical morphology of two hourglass dolphins and four spectacled porpoises. Morphometric measurements and skeletal characteristics aligned with the literature, while internal anatomy (organs and systems) was similar to other odontocetes. Precise and consistent lung measurements were challenging; qualitative assessments indicated relatively large lungs with respect to body size. The spectacled porpoise dorsal fin was uniquely large with a well-developed blood supply; this is hypothesized to act as a thermoregulatory window, though it may also play a role in sexual display in the case of males. Overall, this study provides new data on the anatomy of the hourglass dolphin and spectacled porpoise, contributing insights that may influence future research on these rare species. The findings highlight the importance of anatomical studies as a basis for explaining evolutionary relationships within cetaceans and their ecological roles in the Southern Ocean ecosystems.
Authors
- Carolina Loch (ORCID: https://orcid.org/0000-0001-8949-4008)
- Brian C. W. Kot (ORCID: https://orcid.org/0000-0002-8932-1884)
- Steve Dawson (ORCID: https://orcid.org/0000-0003-3182-0186)
- Emma L. Betty (ORCID: https://orcid.org/0000-0002-9187-1957)
- Kane Fleury (ORCID: https://orcid.org/0000-0003-3524-6329)
- Ros Cole
- Jean‐Marie Graïc (ORCID: https://orcid.org/0000-0002-1974-8356)
- Derek Cox
- Matthew R. Perrott (ORCID: https://orcid.org/0000-0003-0400-7704)
- Rebecca M. Boys (ORCID: https://orcid.org/0000-0001-6427-800X)
- Bruno Cozzi (ORCID: https://orcid.org/0000-0002-7531-7040)
- Trudi Webster (ORCID: https://orcid.org/0000-0002-3507-1162)
- Tommaso Gerussi (ORCID: https://orcid.org/0000-0003-0263-5635)
- Anton van Helden
- Stuart Hunter (ORCID: https://orcid.org/0000-0002-6296-832X)
- Tom Waterhouse
- Emma Burns (ORCID: https://orcid.org/0000-0002-5370-8649)
- Karen A. Stockin (ORCID: https://orcid.org/0000-0002-2981-3983)
- Hannah Hendriks (ORCID: https://orcid.org/0000-0002-8817-8211)
- Tabris Y. T. Chung (ORCID: https://orcid.org/0000-0002-7582-9265)
- Odette Howarth (ORCID: https://orcid.org/0000-0001-6919-0250)
- Sophie White (ORCID: https://orcid.org/0009-0001-9202-9796)
- Henry C. L. Tsui (ORCID: https://orcid.org/0009-0003-1333-9302)
- William Rayment (ORCID: https://orcid.org/0000-0001-9558-5109)
- R. Ewan Fordyce (ORCID: https://orcid.org/0000-0002-2656-730X)
- Ramari Oliphant Stewart (ORCID: https://orcid.org/0000-0002-5023-5778)
- Muriel Johnstone
Institutions
- University of Padua (IT)
- City University of Hong Kong (HK)
- Otago Polytechnic (NZ)
- Hong Kong Jockey Club (HK)
- Penguin Random House (United States) (US)
- Education Trust (US)
- Department of Conservation (NZ)
- Massey University (NZ)
- University of Otago (NZ)
Publication Details
- Journal
- The Anatomical Record
- Published
- 2025-10-22
- DOI
- https://doi.org/10.1002/ar.70045
- Primary Topic
- Marine animal studies overview
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Department of Conservation, New Zealand