Osedax talkovici, 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 : 460-462

Osedax talkovici n. sp.

Figure 3

‘yellow patch’ ( Rouse et al. 2011; Rouse et al. 2015; Vrijenhoek et al. 2009)

Material examined. Holotype: SIO-BIC A 7821 female (GenBank COI sequence MG262313 ), fixed in glutaraldehyde-preserved in ethanol, collected from turkey ( Meleagris gallopavo ) bone deployed at 1018 meters depth in Monterey Submarine Canyon , California (36°46.308’N; 122° 4.981’W) ROV Doc Ricketts dive number 233, June 2, 2011. Paratypes: Females, all fixed in formalin-preserved in ethanol, SIO-BIC A1649 (GenBank COI sequence FJ347621 ), SIO-BIC A7822, A7823, A7824, A7825, A7826 (GenBank COI sequences FJ347620 , 431196, 431197, 431201, 431205), whale ( Eschrichtius robustus ) deployed at 633 meters depth in Monterey Submarine Canyon, California (36°48.178’N; 121°59.677’W) ROV Tiburon dive number 1160, Dec. 18, 2007; Female SIO-BIC A7829 (GenBank COI sequence MG262311 ) and dwarf males (allotypes) SIO-BIC A7830 whale fall at 633 meters depth in Monterey Submarine Canyon, California (36°48.178’N; 121°59.677’W) ROV Doc Ricketts dive number 205, October 26, 2010; Female SIO-BIC A7827 (GenBank COI sequence MG262310 ) and dwarf males (allotypes) SIO-BIC A7828, whale ( Eschrichtius robustus ) deployed at 633 meters depth in Monterey Submarine Canyon, California (36°48.178’N; 121°59.677’W) ROV Doc Ricketts dive number 233, June 2, 2011; Female SIO-BIC A7831 (GenBank COI sequence MG262312 ) on green turtle bone ( Chelonia mydas ), deployed at same locality and date as holotype.

Diagnosis and description. Holotype female ( Figs 3B, C ); in life trunk 1.8 mm long, 0.3 mm wide; crown of palps contracted, 1.5 mm long. Tube gelatinous. Oviduct 0.75 mm ( Figs 3C, D ). In life, palps reddish with blood ( Figs 3A–E ). Pinnules of all four palps oriented dorsally ( Figs 3A, D, E ). Trunk with bright yellow patch on midventral anterior edge ( Figs 3A, B, D ). Clear demarcation into upper and lower trunk ( Fig. 3D ). Ovisac spheroidal in holotype ( Figs 3B, C ), extending laterally, or as simple lobes in other specimens. Roots of holotype longer that the remaining body, extending posteriorly as a single lobate mass ( Figs 3B, C ). In other specimens ( Figs 3A, D, E ), roots as simple lobes or extending laterally in two lobes. Males dwarfs, resembling trochophore larvae, with spermatids and sperm ( Figs 3F, G ).

Distribution. Known from Monterey Bay, California from 633 to 1018 meters depth ( Table 2). It has been found in whale, elephant seal, cow, turkey, turtle and teleost bones.

Etymology. This species is named (noun in the genitive case) for Mark Talkovic, Senior ROV pilot for MBARI, who collected many bones containing Osedax over the years.

Remarks. Osedax talkovici n. sp. is part of Osedax Clade I and forms a well-supported clade with the undescribed species O. ‘mediterranea’ and a clade comprised of Osedax sigridae n. sp. and the undescribed species O. Sagami-5 ( Fig. 1 ). It has a minimum uncorrected distance, for COI, of at least 16% from each of these ( Table 4). The 15 available COI sequences for Osedax talkovici n. sp. ( Table 3) show less that 1% sequence divergence. The most distinguishing feature of Osedax talkovici n. sp. is the bright yellow patch ventrally on the anterior trunk ( Fig. 3 ).

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 3. Osedax talkovici n. sp., previously Osedax ‘yellow patch’. A. Paratype (SIO-BIC A7831) in green turtle (Chelonia mydas) bone deployed at 1018 meters in Monterey Canyon, with bone partially dissected away from specimen.Note distinctive yellow patch on ventral part of the anterior trunk. Palps have dorsally-oriented pinnules. In this specimen, ovisac and roots extend laterally beneath surface of the bone rather than penetrating deeply into bone. B. and C. Holotype (SIO-BIC A7821) in ventrolateral (B) and dorsolateral (C) views.Holotype is a female dissected from turkey (Meleagris gallopavo) bone deployed at 1018 meters. Root mass extended into the bone in this specimen, away from the ovisac. Oocytes are visible in oviduct in C. D. Ventral view of female paratype (SIO-BIC A7831) shown in A., now dissected from green turtle bone. E. Lateral view of paratype (SIO-BIC A7829), a female dissected from whale bone deployed at 633 meters. Pinnules of all palps are oriented dorsally. F. Dwarf male allotype (SIO-BIC A7828) taken from the tube of female paratype (SIO-BIC A7830). Hooked chaetae visible posteriorly, with spermatids in mid-body region and mass of mature sperm anteriorly. G. Anterior end of dwarf male allotype (SIO-BIC A7830) showing sperm mass.