Bryozoa (Cyclostomata and Ctenostomata) from polymetallic nodules in the Russian exploration area, Clarion - Clipperton Fracture Zone, eastern Pacific Ocean-taxon novelty and implications of mining Grischenko, Andrei V. Gordon, Dennis P. Melnik, Viacheslav P. Zootaxa 2018 2018-09-25 4484 1 1 91 3e1cfe1c-67d8-4d7d-a180-d4d86e244898 Grischenko & Gordon & Melnik, 2018 Grischenko & Gordon & Melnik 2018 [151,461,1399,1425] Gymnolaemata Haywardozoidae Haywardozoon GBIF Animalia Ctenostomatida 68 69 Bryozoa species pacificum sp. nov.   Material examined. Holotype: ZIRAS 1/50726, colony encrusting tube of serpulid polychaete detached from nodule, YMG R.V. Yuzhmorgeologiyacruise YMG4–04, Stn 39, 16 August2005, 13.61415° N, 130.82158° W, 5017 m. Additional material: YMG4–07, Stns 134, 143; GLD4–11, Stns 214, 220; GLD4–12, Stns 245, 267; YMG4–14, Stn 322. Total specimens examined eight.   Etymology.Alluding to the first description of the genus in the Pacific Ocean.   Description.Colony encrusting, diffuse, comprising up to c. 12 large zooids, partly uniserially arranged and disjunct ( Figs 47, 48), adjacent zooids connected distally and laterally by very small contact points; highly transparent and apparently colorless in life. Zooids generally mostly elongated, their lateral outlines weakly convex to subparallel or even slightly diverging; bilaterally symmetrical or one side extending outwards as a triangular skirt. Daughter zooids budded distolaterally. Membranous frontal wall gently rising to highest point of zooid at orifice ( Fig. 47G). Orifice wider than long ( Figs 47I, J, 48G), having slightly thickened cuticularized rim with two components—proximal rim more or less transversely C-shaped, concave on inner side; distal rim more or less straight but produced proximally as D-shaped flap that superficially resembles operculum and fits into concavity of proximal rim; edge of flap slightly thickened ( Figs 48G, H).   FIGURE 45.?Anyutidae sp.  incertae sedis. A–D, rotational views of colony ZIRAS 1/50725; note the highly alveolate colony surface and fascicles of variable size. Scale bars: 500 µm.   FIGURE 46.?Anyutidae sp.  incertae sedis. A–G, I–K, colony ZIRAS 1/50725; H, specimen GLD4–12, Stn 257. A, B, apical and oblique lateral views of capitulum (partly damaged); C, alveoli of capitulum surface; D, skeletal microstructure; E, crosssection through fascicle of autozooids and alveolar cavities; F, G, I, J, close-ups of fascicles of varied sizes and zooid dispositions; H, small fascicle in which one peristome has a calcified terminal diaphragm; K, interior wall of broken peristome showing crystallites. Scale bars: A, 500 µm; B, F, 250 µm; C, E, G, 200 µm; D, K, 50 µm; H–J, 100 µm.   FIGURE 47.  Haywardozoon pacificum  n. sp.Specimens stained in Rose Bengal. A, specimen GLD4–11, Stn 214, zooids on a serpulid tube; B–G, holotype, ZIRAS 1/50726, different views of zooids on a serpulid tube; H–J, specimen GLD4–12, Stn 245, respectively showing very lightly stained zooids on serpulid tube and two zooids seen in transmitted light. Abbreviations: bb, brown body; d, diaphragm; dmd, dilator muscles of diaphragm; g, gut; olf, operculum-like flap; rmtc, retractor muscles of tentacle crown; t, tentacle cluster; v, vestibule. Scale bars: A–H, 500 µm; I, J, 100 µm.   FIGURE 48.  Haywardozoon pacificum  n. sp.Holotype, ZIRAS 1/50726. A–F, autozooids disposed on serpulid tube, all slightly collapsed through drying; G, H, orificial region showing operculum-like flap; I, autozooid, with dwarf ancestrular at lower right; J, close-up of ancestrula. Scale bars: A, F, 500 µm; B–E, I, 250 µm; G, 200 µm; H, I, 100 µm. Vestibule more or less parallel-sided, a little longer than broad, 28–33% polypide length, with strongly developed parieto-diaphragmatic musculature at proximolateral corners ( Fig. 47I, J). Vestibule 0.097–0.123 mmlong; retracted tentacle crown 0.265–0.311 mmlong, tentacle number not determined. No stomach gizzard. Small brown bodies or fragments of brown bodies retained in cystid ( Fig. 47I, J). Anchor point of polypide retractor muscles not clearly seen. One very small oval zooid encountered that may be ancestrula, very close to proximal curved ‘tail’ of large zooid that may have budded from it ( Fig. 48I). Orifice of small zooid ( Fig. 48J) identical in form to that of large zooids).  Measurements (mm). Holotype, ZIRAS 1/50726 ( Figs 47, 48): ZL 0.703–1.450 (1.048 ± 0.211); ZW 0.438–0.852 (0.714 ± 0.117); OrL 0.088–0.140 (0.120 ± 0.018); OrW 0.150–0.203 (0.172 ± 0.019). Ancestrula ( n= 1): AnL 0.322; AnW 0.221; AnOrL 0.027; AnOrW 0.059.   Remarks.We follow Jebram (1986)in including Haywardozoidaein superfamily Hislopioidea, and Reverter- Gil et al. (2016) concerning the emended spelling of the family name. Our material conforms to the overall characters of the two described Atlantic species of  Haywardozoon, especially  H. inarmatum, which has a similar budding pattern and zooid shape, but from which it differs in details of the orifice. D’Hondt (1983) characterized the polypide of  Haywardozoonspecies as “minute … inhabiting only a very small portion of the zoecial cavity”, which is not the case in  H. pacificum  n. sp.The CCZ colonies were found only on tubes of serpulid polychaetes attached to nodules.   Distribution.Recorded from eight stations within coordinates 12.26676– 13.61415° N, 130.82158– 134.59811° W, at depth range 4741–5050 m.