Calyssopora volcano, Grischenko & Gordon & Melnik, 2018

Grischenko, Andrei V., Gordon, Dennis P. & Melnik, Viacheslav P., 2018, 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, Zootaxa 4484 (1), pp. 1-91 : 45-46

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.

Figures

FIGURE 2. Colonies of some cyclostome bryozoans, in vivo, attached to polymetallic nodules. A–E, Pandanipora helix n. gen., n. sp.: A, specimen GLD4–09, Stn 190; B, specimen GLD4–12, Stn 262; C, specimen YMG4–07, Stn 143; D, specimen YMG4–13, Stn 295; E, specimen GLD 4–11, Stn 212. F, Tubuliporina sp. indet., specimen YMG18–01, Stn 7. G, H, Abyssoecia elevata n. gen., n. sp.: G, specimen GLD4–09, Stn 196; H, specimen GLD4–09, Stn 191. I, Discantenna metallica n. sp.: specimen GLD4–11, Stn 224. J, K, Frontohornera frontalis n. gen., n. sp.: J, specimen YMG4–07, Stn 124; K, specimen GLD4–11, Stn 210. L, Alyonushka hystricosa n. gen., n. sp.: specimen GLD4–09, Stn 199. M, Calyssopora volcano n. gen., n. sp.: specimen YMG18–01, Stn 33. N, O, Anyuta anastema n. gen., n. sp.: N, specimen GLD4–09, Stn 180; O, specimen YMG4–06, Stn 71. Scale bars: 1 mm.

FIGURE 28. Calyssopora volcano n. gen., n. sp. A, B, holotype, ZIRAS 1/50714, with a single gonozooid; C, D, paratype 1, ZIRAS 2/50715, with two ooeciostomes and therefore two gonozooids presumed; E, F, paratype 2, ZIRAS 3/50716, with possibly newly completed gonozooid, having large alveolate spaces at left-hand periphery. Scale bars: 250 µm.

FIGURE 29. Calyssopora volcano n. gen., n. sp. A, D, L, holotype, ZIRAS 1/50714; B, E, G–I, K, paratype 1, ZIRAS 2/ 50715; C, F, J, paratype 2, ZIRAS 3/50716. A–C, oblique profiles of fertile colonies respectively shown in Fig. 28A, B, Fig. 28B, C and Fig. 28E, F; D–F, peristome of gonozooids respectively shown in A–C; G, calyx periphery showing short autozooidal peristomes, shallow alveoli and pores; H, skeletal microstructure of slope of ooeciostome; I, peristomes in oblique profile; J, abfrontal side of peristomes; K, two autozooidal apertures with large alveolus between; L, oblique bilaterally symmetrical autozooidal apertures. Scale bars: A–C, J, 250 µm; D–G, I, K, L, 150 µm; H, 25 µm.

FIGURE 30. Calyssopora volcano n. gen., n. sp. Progressive stages of development of ancestrular and young colonies. A, B, specimen YMG4–13, Stn 291; C, D, specimen YMG4–07, Stn 139; E, F, specimen YMG4–14, Stn 358; G, H, specimen YMG4–04, Stn 57; I, J, specimen YMG4–13, Stn 283; K, L, specimen YMG4–13, Stn 300; M, N, specimen GLD4–09, Stn 198; O, P, specimen YMG4–13, Stn 274. A, B, four-zooid stage; C–F, four–five-zooid stages; G–J, five–six-zooid stages; K–P, later submature stages with calyciform colony center adequately structured with trabeculae and alveoli to support gonozooid development. Scale bars: 200 µm.