Nautilus vitiensis, Barord & Combosch & Giribet & Landman & Lemer & Veloso & Ward, 2023

Barord, Gregory J., Combosch, David J., Giribet, Gonzalo, Landman, Neil, Lemer, Sarah, Veloso, Job & Ward, Peter D., 2023, Three new species of Nautilus Linnaeus, 1758 (Mollusca, Cephalopoda) from the Coral Sea and South Pacific, ZooKeys 1143, pp. 51-69 : 51

Nautilus vitiensis sp. nov.

Fig. 4

Type material.

Holotype: accessioned at University of South Pacific Marine Station (USPMS) #12232 (Fig. 4 ). Collected from Suva Harbour, Fiji, 18°07'10.2"S, 178°24'45.0"E, at depths between 250 and 300 m on 30 Jul. 2018.

Diagnosis.

The following characteristics distinguish Nautilus vitiensis sp. nov. from other species within the genus Nautilus : 15-30% pigment coloration on shell, more than in N. pompilius and less than in the other species described here; two color pattern morphs present, with both full (stripes from venter to umbilicus) and "umbilical white patch" variety, where stripes flowing down from venter stop short of umbilical region; shell color patterns composed of simple stripes beginning at venter and then extending down the side of shell; these are large and unbranched and are among the simplest of all nautilus shell coloration patterns. The largest specimens of the new species are smaller than the smallest mature N. pompilius , and this species is in general smaller than the other two new species described here, but there is certain overlap.

Description.

Nautiliconic, shell with umbilical plug, whorl higher than broad at maturity. Periostracum entirely absent in mature and near mature specimens; shell surface ornamented with growth lines parallel to apertural shape; no cross-hatching or ornament perpendicular to growth lines; low rugae. Hood morphology consists of low, elliptical white protuberances barely projecting above hood surface on either side of two long, raised, parallel white stripes running centrally down hood from shell whorl to aperture. White protuberances found between stripes on the entire central section (see hood details on Suppl. material 1: video 1; Fig. 7 ). Mean diameter of adult shell 149.3 mm, s.d. 7.548 (see range of measured specimens in Table 1 ).

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).

Figures

Figure 4. Lateral view of Nautilus vitiensis sp. nov., holotype USPMS # 12232.

Figure 7. Underwater photos of living Nautilus A, B N. samoaensis sp. nov. C N. vanuatuensis sp. nov. D N. vitiensis sp. nov.