Osedax bryani, 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 : 483

Osedax bryani n. sp.

Figure 18

‘MB17’ ( Rouse et al. 2015; Salathé & Vrijenhoek 2012)

Material examined. Holotype: SIO-BIC 4619 , Female (GenBank COI sequence JX280609 ), fixed in formalin preserved in ethanol, collected from a whale carcass 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.

Diagnosis and description. Holotype and only available specimen female ( Figs18A, B ); in life trunk 4 mm long, 1.8 mm wide; crown of palps somewhat contracted, curled, 4.5 mm long. Pinnules of all palps oriented dorsally and the oviduct lying between the dorsalmost pair of palps. Oviduct extends from trunk into crown for 5 mm ( Figs 18A, B ). In life, pinnules of palps reddish, otherwise no obvious pigment. Trunk with white ring around anterior margin; ring broken mid-dorsally by oviduct and mid-ventrally by and oval unpigmented patch. Clear demarcation of upper and lower trunk. Ovisac in holotype, damaged, a large ellipsoidal mass ( Figs 18A, B ). Green root tissue visible but torn. Possible male found in tube of holotype, with chaetal-bearing segments inflated; found in tube lumen of females, lost following microscope slide preparation ( Fig. 18C ).

Distribution. Known from Monterey Bay, California from 1820 meters depth in whale bone.

Etymology. This species is named (noun in the genitive case) in honor of Bryan Touryan-Schaefer, ROV Pilot/ Technician for MBARI, who collected many bones with Osedax over the years.

Remarks. Osedax bryani n. sp. is part of Osedax Clade V and is sister taxon to the O. rubiplumus and O. roseus clade ( Fig. 1 ). It shows a minimum uncorrected distance, for COI, of ~15% to O. rubiplumus ( Table 4). Osedax bryani n. sp. shares distinguishing feature of a white ring around the anterior part of the trunk with O. randyi n. sp. and O. frankpressi and as with Clade II of Osedax , these species likely need to be distinguished with DNA data. The documentation of dwarf males in Osedax bryani n. sp. is the first for this species, which was listed as unknown in Rouse et al. (2015).

Figures

FIGURE 1. Osedax phylogenetic analyses. Osedax multi-gene phylogeny with Monilifera as outgroup.Maximum likelihood tree topology based on a partitioned dataset of five gene segments (MAFFT-aligned) for data shown in Table 2. The Bayesian analyses gave the same topology. Bootstrap support % (BS) is at each node, followed by posterior probability (PP) from the MrBayes analyses. * indicates values were ± 95% (BS) and 0.95 (PP). Missing values indicate BS <50% and PP <0.7. Six major Osedax clades are distinguished, following Vrijenhoek et al. (2009), Rouse et al. (2015) and Taboada et al. (2015). The various forms of palps (or absence thereof in the case of O. jabba n. sp.) are indicated for the major clades but these are not intended to indicate apomorphic states.

FIGURE 18. Osedax bryani n. sp., previously Osedax ‘MB17’. A. Micrograph of live holotype (SIO-BIC A4619), female in dorsal view,removed from its tubeand showing crown, trunk and part of ovisac.Oviductlies between dorsalmostpair of palps. Little apparent pigmentation around anterior trunk B. Ventral view of live holotype (SIO-BIC A4619) showing white pigmentation anteriorly with midventral gap. Pinnules of all palps oriented dorsally. Arrow indicates oval unpigmented patch. C. Differential interference micrograph (from a stack series) of a solitary male (or larval stage?) dissected from tube of holotype (SIO-BIC A4619). Some hooks are visible in expanded posterior region. No mature sperm is visible though there are several bundles of spermatids.