Osedax westernflyer, Rouse & Goffredi & Johnson & Vrijenhoek, 2018

Rouse, Greg W., Goffredi, Shana K., Johnson, Shannon B. & Vrijenhoek, Robert C., 2018, An inordinate fondness for Osedax (Siboglinidae: Annelida): Fourteen new species of bone worms from California, Zootaxa 4377 (4), pp. 451-489 : 465

Osedax westernflyer n. sp.

Figure 5

‘nude-palp-D’ ( Rouse et al. 2011; Rouse et al. 2015; Vrijenhoek et al. 2009) ‘Sagami 8’ (GenBank COI sequence FM998110 ; Pradillon et al. unpublished)

Material examined. Holotype: SIO-BIC A 1645 , Female (GenBank COI sequence MG262303 ), fixed in formalin preserved in ethanol, collected from a whale carcass ( Eschrichtius robustus ) deployed at 1820 meters depth in Monterey Submarine Canyon , California (36°42.496’N; 122°6.316’W), ROV Doc Ricketts dive number 12, March 13, 2009. Paratypes: All females, fixed in formalin preserved in ethanol, SIO-BIC A7802, A7803 (GenBank COI sequence MG262302 , MG262304 ), same locality and date as holotype.

Diagnosis and description. Holotype female ( Fig. 5C ); in life trunk 2.8 mm long, 0.5 mm wide; crown of four palps, 3.5 mm long. Tube gelatinous, thin, fitting about trunk and base of crown, 3 mm long ( Fig. 5C ). Oviduct among palps 2.3 mm long ( Figs 5 A-C). In life, palps with white patches with no visible blood vessels, without obvious pinnules ( Figs 5 A-C). Trunk with demarcation into upper and lower trunk ( Fig. 5C ), white pigment patch mid-ventrally on anterior tip of trunk ( Figs 5B, C ). Ovisac 1.5 mm by 1 mm with lobate greenish roots extending outwards ( Figs 5B, C ). Males not found.

Distribution. Known from Monterey Bay, California from 1820 meters depth and Sagami, Bay Japan ( Table 2). It has been found in cow and whale bones.

Etymology. This species is named (noun in apposition) for the Research Vessel Western Flyer, which has been critical to Osedax studies.

Remarks. Osedax westernflyer n. sp. is part of Osedax Clade II and is closest relative to O. knutei n. sp., with a minimum divergence of 16 % for COI, though it shows a smaller distance, 14% to O. docricketts n. sp. ( Table 4). The four available COI sequences for Osedax westernflyer n. sp. from California ( Table 3) are less that 1% divergent. The holotype and two paratypes all showed distinct white pigment on the palps, though these were all collected from one patch of bone and the color may have been caused by a bacterial coating. A single COI sequence on GenBank ( FM998110 ), referred to Osedax sp. Sagami-8 (Pradillon et al., unpublished), is less than 1% divergent from the four California COI sequences ( Table 4), leading us to propose that Osedax westernflyer n. sp. is also found in Japan. There is little to distinguish Osedax docricketts n. sp. from other Clade II species, apart from the white pigmentation at the anterior end of the trunk and on the pigmentation on palps.

Figures

FIGURE 5. Osedax westernflyer n. sp., previously Osedax ‘nude-palp-D’. A. Lateral view of Osedax westernflyer n. sp. paratype (SIO-BIC A7802), with distinctive white pigment (or bacteria) on palps, while still living and in degraded bone. B. Ventro-lateral view of paratype (SIO-BIC A7803) dissected from bone and still alive. Note ventral lobe-like projection of anterior trunk beneath palps (arrow). Oviduct is about half length of the palps. C. Dorsal view of holotype (SIO-BIC A1645) dissected from bone and still alive.