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| A, B Nautilus samoaensis sp. nov. C N. vanuatuensis sp. nov. D N. vitiensis sp. nov. Barord, Combosch, Giribet, Landman, Lemer, Veloso & Ward, 2023 |
Abstract
Nautiloids are a charismatic group of marine molluscs best known for their rich fossil record, but today they are restricted to a handful of species in the family Nautilidae from around the Coral Triangle. Recent genetic work has shown a disconnect between traditional species, originally defined on shell characters, but now with new findings from genetic structure of various Nautilus populations. Here, three new species of Nautilus from the Coral Sea and South Pacific region are formally named using observations of shell and soft anatomical data augmented by genetic information: N. samoaensis sp. nov. (from American Samoa), N. vitiensis sp. nov. (from Fiji), and N. vanuatuensis sp. nov. (from Vanuatu). The formal naming of these three species is timely considering the new and recently published information on genetic structure, geographic occurrence, and new morphological characters, including color patterns of shell and soft part morphology of hood, and will aid in managing these possibly endangered animals. As recently proposed from genetic analyses, there is a strong geographic component affecting taxonomy, with the new species coming from larger island groups that are separated by at least 200 km of deep water (greater than 800 m) from other Nautilus populations and potential habitats. Nautilid shells implode at depths greater than 800 m and depth therefore acts as a biogeographical barrier separating these species. This isolation, coupled with the unique, endemic species in each locale, are important considerations for the conservation management of the extant Nautilus species and populations.
Keywords: Conservation, deep-sea, Nautilidae, Nautilus, taxonomy
Class Cephalopoda Cuvier, 1795
Order Ectocochliata Schwartz, 1894
Subclass Nautiloidea Agassiz, 1847
Family Nautilidae de Blainville, 1825
Genus Nautilus Linnaeus, 1758
Nautilus pompilius Linnaeus, 1758
(type species of Nautilus)
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| Underwater photos of living Nautilus A, B Nautilus samoaensis sp. nov. C N. vanuatuensis sp. nov. D N. vitiensis sp. nov. |
Nautilus vitiensis sp. nov.
Etymology: The specific epithet, an adjective, refers to the type locality, the island of Viti Levu, Fiji, where the type specimen plus additional released specimens sampled for genetic work were collected.
Habitat and distribution: Nautilus vitiensis sp. nov. inhabits areas along the coast of Viti Levu, Fiji at Suva Harbour and Pacific Harbour. Specimens were collected and filmed (Suppl. material 1: video 1) at depths between 200–400 m (Tajika et al. 2022).
Nautilus samoaensis sp. nov.
Etymology: The specific epithet, an adjective, refers to the type locality, American Samoa.
Habitat and distribution: Nautilus samoaensis sp. nov. inhabits areas near Pago Pago, American Samoa. Specimens were collected and filmed (Suppl. material 2: video 2) at depths between 200 and 400 m.
Nautilus vanuatuensis sp. nov.
Etymology: The specific epithet, an adjective, refers to the type locality, Vanuatu, where all the known specimens have been collected.
Habitat and distribution: Nautilus vanuatuensis inhabits sites within Mele Bay, Vanuatu. Specimens were collected and filmed (Suppl. material 3: video 3) at depths of 200–400 m.
Conclusions:
The three species, Nautilus vitiensis, N. samoaensis, and N. vanuatuensis represent populations of nautiluses on the easternmost edge of the overall habitat range of Nautilus. The designation of these three populations as distinct species provides insight into evolutionary radiation of the genus and clarification for future conservation practices.
Gregory J. Barord, David J. Combosch, Gonzalo Giribet, Neil Landman, Sarah Lemer, Job Veloso and Peter D. Ward. 2023. Three New Species of Nautilus Linnaeus, 1758 (Mollusca, Cephalopoda) from the Coral Sea and South Pacific. ZooKeys. 1143: 51-69. DOI: 10.3897/zookeys.1143.84427
