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 Author Grischenko, Andrei V. Author Gordon, Dennis P. Author Melnik, Viacheslav P. text Zootaxa 2018 2018-09-25 4484 1 1 91 journal article 29502 10.11646/zootaxa.4484.1.1 74b777c9-eae0-4770-8c86-dcbb10fb06b3 1175-5326 1437848 D66524CF-9C6D-4DF4-8CA2-B2C9708CF5FD Calyssopora volcano n. sp. ( Figs 2M , 28–30 ) Material examined. Holotype : ZIRAS 1/50714, colony attached to nodule particle, YMG R.V. Yuzhmorgeologiya cruise YMG4–14, Stn 357, 18 January 2016 , 14.03237° N, 131.74563° W, 5073 m . Paratype 1: ZIRAS 2/50715, colony attached to nodule particle, YMG R.V. Gelendzhik cruise GLD4–12, Stn 251, 6 April 2013 , 12.80823° N, 132.69682° W, 4837 m . Paratype 2: ZIRAS 3/50716, colony attached to nodule particle, YMG R.V. Yuzhmorgeologiya cruise YMG4–14, Stn 325, 20 December 2015 , 13.58832° N, 131.68838° W, 5031 m . Additional material : YMG18–01, Stns 7, 15, 24, 33; YMG4–04, Stn 57; YMG4–06, Stns 70, 92, 99, 101, 103; YMG4–07, Stn 139; GLD4–09, Stns 173, 178, 185, 198; GLD4–11, Stn 216; GLD4–12, Stn 271; YMG4–13, Stns 274, 283, 291, 300; YMG4–14, Stns 348, 358. Total specimens examined 27. Etymology. Anglicized spelling of the Italian vulcano , alluding to the volcano-like gonozooid with its craterlike ooeciopore; used as a noun in apposition. Description. Colony erect, thickly pedunculate, with autozooidal peristomes radiating outwards around periphery of capitulum ( Fig. 28 ), up to maximum of 22 peristomes in single irregular whorl. Skeletal surface of column with weakly defined ridges and furrows, granular-tubercular ( Fig. 29A–C ), with sparse pores; surface ultrastructure with irregularly arranged crystallites lacking obvious preferred growth direction ( Fig. 29H ). Capitulum of submature colony infundibuliform ( Fig. 30L ), bottom of funnel comprising deep alveolar chambers delimited by trabeculae ( Fig. 30O ). Additional thin walls cross gaps between adjacent peristomes at colony periphery where additional autozooidal chambers develop to fill vacancies in whorl as colony expands ( Figs 29J , 30A, I, O ); some of these openings seem to represent adjacent extrazooidal spaces, their openings narrowed in mature colony ( Fig. 29B ). Increasing calcification reduces openings in calyx center to expanding porous platform that serves as irregular open ‘floor’ to gonozooid(s) ( Fig. 30O ). Autozooidal peristomes in single subregular series, skeletal surface like that of column, with sparse, simple pores ( Fig. 29G ) having irregular outline, tending to be in single longitudinal series on lower side ( Fig. 29L ). Developing apertures slightly irregular, subrounded ( Fig. 29A, K ) or having bilateral symmetry, opening obliquely outwards and downwards ( Fig. 29L ). No spinules or prickles on inner surface of peristome tubes ( Fig. 29K, L ). Gonozooid large and capacious ( Fig. 28A, B ), 1–2 per mature colony ( Fig. 28C, D ). Floor of gonozooid not discrete and continuous. If solo, gonozooid in center of calyx or to one side, chamber roof sloping upwards to ooeciostome ( Fig. 29A–D ), resembling volcanic cone in profile, with lateral ridges and furrows and porous cancelli that are mostly on periphery of gonozooid ( Fig. 29D ); ooeciopore variably elevated, subcircular to suboval ( Fig. 28A, C, E ). Surface microstructure of gonozooid like that of column and zooidal peristomes, with weak imbrication of irregular crystallites ( Fig. 29H ). Ancestrula not seen in isolation, but evidently erect judging from smallest (four-zooid) colony stages seen ( Fig. 30A, B ). Trabeculae form in center of developing colony to support colony elevation and expansion, with extrazooidal alveolar spaces between trabeculae ( Fig. 30A, C, I, K, M, O ). Measurements (mm). Holotype , ZIRAS 1/50714 ( Fig. 28A, B ): Colony height 1.78; capitulum 2.07 × 1.98; base at substratum 0.85 × 0.93 with narrowest cross-section 0.60 × 0.64; ZL 0.591–0.980 (0.809 ± 0.122); PeL 0.372–0.597 (0.492 ± 0.069); PeD 0.137–0.177 (0.155 ± 0.013); ApL 0.152–0.185 (0.172 ± 0.011); ApW 0.128–0.153 (0.138 ± 0.009). Gonozooid ( n = 1): GZL 0.644; GZW 0.817; OsL 0.155; OsW 0.127; OsH 0.138; OpL 0.133; OpW 0.119. Remarks. Calyssopora volcano n. sp. differs from Calyssopora vasiformis n. sp. (below) in overall form and the number of peristomes, and from Calyssopora clarionensis n. sp. , in having volcaniform gonozooids in which the frontal surface rises to a frontally facing ooeciostome with a crater-like ooeciopore. The gonozooid in A. clarionensis is rather more bulging than volcaniform, and the ooeciostome is strongly curved and hood-like. Dartevellopora granulosa Gordon & Taylor, 2010 was only doubtfully included in Dartevellopora when described. In some respects, it resembles the species of Calyssopora , but differs in that there is a clear differentiation between a smoothly spreading skirt-like base and pustulose erect part of the column. The center of its capitulum is less calyciform than in Calyssopora , comprising a subhorizontal platform with evenly distributed circular pores, unlike the open alveolate and trabecular mesh of Calyssopora . Until fertile colonies of D. granulosa are found, its generic attribution must remain problematic. Distribution. Recorded from 26 stations within coordinates 12.51953– 14.16490° N , 129.04471– 134.60008° W , at depth range 4672–5149 m .