A revisited phylogeography of Nautilus pompilius

Abstract

The cephalopod genus Nautilus is considered a “living fossil” with a contested number of extant and extinct species, and a benthic lifestyle that limits movement of animals between isolated seamounts and landmasses in the Indo‐Pacific. Nautiluses are fished for their shells, most heavily in the Philippines, and these fisheries have little monitoring or regulation. Here, we evaluate the hypothesis that multiple species of Nautilus (e.g., N. belauensis, N. repertus and N. stenomphalus) are in fact one species with a diverse phenotypic and geologic range. Using mitochondrial markers, we show that nautiluses from the Philippines, eastern Australia (Great Barrier Reef), Vanuatu, American Samoa, and Fiji fall into distinct geographical clades. For phylogenetic analysis of species complexes across the range of nautilus, we included sequences of Nautilus pompilius and other Nautilus species from GenBank from localities sampled in this study and others. We found that specimens from Western Australia cluster with samples from the Philippines, suggesting that interbreeding may be occurring between those locations, or that there is limited genetic drift due to large effective population sizes. Intriguingly, our data also show that nautilus identified in other studies as N. belauensis, N. stenomphalus, or N. repertus are likely N. pompilius displaying a diversity of morphological characters, suggesting that there is significant phenotypic plasticity within N. pompilius.

Postmortem transport in fossil and modern shelled cephalopods

“…However, drifted nautilid shells are actually fairly rare ( Wani et al, 2005 ) and only one extant nautilid species, N. pompilius , shows widely distributed drift shells. The limited geographic distributions of most nautilid species are consistent with evidence for genetic divergence of geographically separated populations ( Wray et al, 1995 ; Bonnaud, Ozouf-Costaz & Boucher-Rodoni, 2004 ; Sinclair et al, 2007 ; Sinclair et al, 2011 ; Bonacum et al, 2011 ; Williams et al, 2015 ; Vandepas et al, 2016 ). The wider distribution of N. pompilius may be real or the result of pooling multiple genetically distinct populations into single named species.…”

“…The wider distribution of N. pompilius may be real or the result of pooling multiple genetically distinct populations into single named species. N. pompilius does appear to contain more genetic variation than other nautilid species, and may be paraphyletic, with N. stenomphalus and N. belauensis falling within N. pompilius sensu latu ( Bonacum et al, 2011 ; Vandepas et al, 2016 ; Combosch et al, 2017 ; Saunders, Greenfest-Allen & Ward, 2017 ). Hence, the wide distribution of N. pompilius drift shells could actually be caused by the conflation of smaller drift ranges of separate populations.…”

Demographic disequilibrium in living nautiloids (Nautilus and Allonautilus): Canary in the coal mines?

“…Nautiloid genetic studies do not have a long tradition, but there has been a flourish of activity in recent years [29, 30, 31, 32, 33, 34, 35, 36]. By contrast, the taxonomy of extant nautiloids spans more than two centuries, with two genera, eleven species, two subspecies and six variants having been named [10, 36].…”

Novel feeding and mating behaviors of a population of nautiluses, Nautilus belauensis, in Palau

“…The nautiluses of Palau represent the northernmost range of Family Nautilidae with no known historical fisheries in the region. In the literature, these nautiluses have been described morphologically as Nautilus belauensis 16 and recent genetic analyses have provided increased support for N. belauensis as a distinct species 17,18 , apart from the widespread Nautilus pompilius , though this has not been settled. However, for this paper, we will refer to the nautiluses of Palau as Nautilus belauensis to avoid confusion between other populations of nautiluses.…”