Browsing by Author "Hendriks H"

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    A contribution to the anatomy of two rare cetacean species: The hourglass dolphin (Cephalorhynchus cruciger) and the spectacled porpoise (Phocoena dioptrica)
    (Wiley Periodicals LLC on behalf of American Association for Anatomy, 2025-10-22) Graïc J-M; Gerussi T; Cozzi B; Boys RM; Kot BCW; Perrott MR; Fleury K; Chung TYT; Tsui HCL; Burns E; Webster T; Hunter S; Betty EL; Howarth O; Loch C; White S; Dawson S; Rayment W; Cole R; Cox D; Waterhouse T; Hendriks H; van Helden A; Johnstone M; Stewart RO; Fordyce RE; Stockin KA
    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.
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    A contribution to the anatomy of two rare cetacean species: the hourglass dolphin (Lagenorhynchus cruciger) and the spectacled porpoise (Phocoena dioptrica)
    (2025-03-26) Graïc J-M; Gerussi T; Cozzi B; Boys RM; Kot BCW; Perrott MR; Fleury K; Chung TYT; Tsui HCL; Burns E; Webster T; Hunter S; Betty EL; Howarth O; Loch C; White S; Dawson S; Rayment W; Cole R; Cox D; Waterhouse T; Hendriks H; van Helden A; Johnstone M; Stewart RO; Fordyce RE; Stockin KA
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    A piece of the puzzle: analyses of recent strandings and historical records reveal new genetic and ecological insights on New Zealand sperm whales
    (1/01/2022) Palmer E; Alexander A; Liggins L; Guerra M; Bury SJ; Hendriks H; Stockin KA; Peters KJ
    Cetacean strandings provide important opportunities to extend current knowledge on species or populations, particularly for species that are notoriously difficult to study, such as sperm whales Physeter macrocephalus (parāoa). Between 25 May and 9 June 2018, 13 male sperm whales stranded in Taranaki, New Zealand (NZ), with an additional male stranding 1 mo later in Clifford Bay, Marlborough. We profiled these 14 males for mitochondrial DNA (mtDNA) and carbon and nitrogen stable isotopes to examine their similarity to sperm whales from other geographic areas. Analyses of mtDNA revealed 7 haplotypes, including 1 not previously described (‘New’), and an additional haplotype (‘M’) new to NZ that had been previously reported in sperm whales of the Pacific region. Analysis of rare haplotypes found in NZ males suggested genetic links within NZ and the Southwest Pacific. Differences in stable isotope ratios indicated that, despite the close temporal proximity of these stranding events, individuals originated from at least 2 separate groups, with the whale stranded in Clifford Bay identified as being a regular visitor to Kaikōura, South Island. The analysis of stranding records in NZ dating back to 1873 indicated an increase in recorded single strandings since 1970, and a peak in single strandings in the austral summer months, but no seasonality for mass strandings. Sex predicted latitudinal location for single strandings, with 95.1% of female strandings occurring north of 42° S, fitting the general global distribution of female sperm whales limited to lower latitudes. This study provides the first temporal and spatial assessment of sperm whale strandings in NZ and highlights the need for future research on movements and genetic exchange between NZ sperm whales and sperm whales in the wider Pacific region.