Osedax docricketts, 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 : 464

Osedax docricketts n. sp.

Figure 4E

‘nude-palp-C’ ( Higgs et al. 2014; Rouse et al. 2011; Rouse et al. 2015; Vrijenhoek et al. 2009) ‘Sagami-6’ (GenBank COI sequence series FM998088 - FM998107 ; Pradillon et al. unpublished)

Holotype: SIO-BIC A 1644 , Female (GenBank COI sequence FJ347626 ), fixed in formalin preserved in ethanol, collected from whale fall deployed at 1018 meters depth in Monterey Submarine Canyon , California (36°46.308’N; 122° 4.981’W), ROV Tiburon dive number 1049, Oct. 25, 2006.

Diagnosis and description. Holotype incomplete female; preserved trunk 0. 5 mm long, 0.2 mm wide; crown of four palps, 2 mm long ( Fig. 4E ). Tube gelatinous cylinder around trunk and base of palps. Oviduct not discerned. In life, palps white with some reddish patches. Palps without obvious pinnules ( Fig. 4E ). Trunk with no obvious demarcation into upper and lower trunk, or any pigmentation. Ovisac mostly missing in holotype, some traces of roots present. Males not seen.

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

found living on cow and whale bones.

Etymology. This species is named (noun in apposition) for the ROV Doc Ricketts, which was used to collect many Osedax specimens.

Remarks. Osedax docricketts n. sp. is part of Osedax Clade II, which all show apinnulate palps, and is closest relative to the clade comprised of Osedax westernflye r n. sp. and O. knutei n. sp. (minimum divergence of 15%) though it shows smaller distance (14%) to other taxa such as O. lonnyi n. sp. ( Table 4). The four available COI sequences for Osedax docricketts n. sp. from California ( Table 3) show less that 1% sequence divergence. The only retained specimen is the holotype as the others were destroyed for sequencing and the holotype itself is only a partial specimen. Twenty additional COI sequences were referred to Osedax sp. Sagami-6 (Pradillon et al., GenBank, unpublished). Together, the four California and 11 of the Japanese sequences ( FM998088 , FM998089 , FM998091 , FM998093 , FM998094 , FM998098 , FM998099 , FM998100 , FM998101 , FM998103 , FM998107 ) encompass less than 1% sequence divergence; so, we propose that Osedax docricketts n. sp. is also found in Japan. The nine remaining Japanese specimens with>2.4% uncorrected pairwise distance from the 11 Japanese sequences (GenBank sequences: FM998090 , FM998092 , FM998095 , FM998096 , FM998097 , FM998102 , FM998104 , FM998105 , FM998106 ) require further investigation before their assignment to Osedax docricketts n. sp. can be justified. See Table 4 for comparison of California Osedax docricketts n. sp. versus Japanese Sagami-6 representative sequences. There is little to distinguish Osedax docricketts n. sp. from other Clade II species.

Figures

FIGURE 4. Osedax tiburon n. sp., previously Osedax ‘nude-palp-A’; Osedax ventana n. sp., previously Osedax ‘nude-palp- B’; Osedax docricketts n. sp., previously Osedax ’nude-palp-C’. A. Lateral view of Osedax tiburon n. sp. in situ in cow bone before dissection.Elongate apinnulate (‘nude’) palps are within a gelatinous tube. B. Osedax tiburon n. sp. preserved holotype (SIO-BIC A7817), removed from cow bone, showing elongate palps clustered together, obscuring oviduct. Trunk is relatively short and ovisac and roots were largely removed for DNA sequencing.C. Osedax tiburon n. sp. preserved paratype (SIO-BIC A7818) removed from cow bone, also showing elongate palps clustered together, obscuring oviduct. D. Holotype (SIO-BIC A1643) of Osedax ventana n.sp. beforeremoval from cow bone deployed at 2898 meters depth inMonterey Canyon.Elongate apinnulate (‘nude’) palps are within gelatinous tube and are all that were retained for this species. E. Holotype (SIO-BIC A1644) of Osedax docricketts n. sp. incomplete after dissection, and before preservation.