Calyssopora vasiformis, 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 : 46-51

Calyssopora vasiformis n. sp.

( Figs 31 , 32 )

Material examined. Holotype: ZIRAS 1/50717, colony detached from nodule, YMG R.V. Gelendzhik cruise GLD4–11, Stn 203, 17 April 2012, 13.45102° N, 133.17315° W, 4812 m. Additional material: GLD4–11, Stns 201, 228. Total specimens examined three.

Etymology. Latin, vas, vessel, and forma, shape, alluding to the form of the colony.

Description. Colony erect, pedunculate, with autozooidal peristomes radiating outwards around periphery of radially symmetrical capitulum, up to maximum of six peristomes in single whorl ( Fig. 31A–E, G, H ), with additional non-peristomate alveolar openings below. Column longer than capitulum, attached by disk-like ( Fig. 31A–D, H ) or smaller base ( Fig. 32B–D, F–H ), depending on size. Colony surface malleated ( Fig. 31A–D, G ) except for proximal third or half of column, which has narrow ridges and furrows; each malleation (dimple) surrounded by distinct angular ridge ( Fig. 31J, K ); pores simple, very sparse ( Fig. 31G, J, K ). Surface ultrastructure generally of imbricated platy crystallites or these smaller, irregularly arranged and lacking preferred growth direction. Capitulum shallowly calyciform in immature colony ( Fig. 32H ), calyx center with trabeculae and alveoli ( Fig. 32A, E ).

Autozooidal peristomes short, in single series; apertures subrounded, facing obliquely outwards, their rims slightly irregular but entire. Inner surface of peristome tubes smooth to lightly textured, no pustules or spinules ( Fig. 31G, J ).

Gonozooid solitary, capacious, occupying calyx center ( Fig. 31E, H, J ), weakly domed ( Fig. 31A–D, G ), ooeciostome almost non-existent, with proportionally large circular ooeciopore in center ( Fig. 31I ). Gonozooid surface malleated frontally, with at least one pore in each dimple, periphery of chamber alveolate, each alveolus with pore ( Fig. 31E, F, J ).

Ancestrula and very small colony stages not seen. Smallest colony encountered had perhaps four functioning peristomes and others developing, its center comprising small triangular shelf with small alveoli ( Fig. 32A ).

Measurements (mm). Holotype, ZIRAS 1/50717 ( Fig. 31 ): Colony height 2.55; capitulum 1.08 × 0.85; base at substratum 0.73 × 0.66; stalk minimal diameter 0.28; ZL 0.275–0.325 (0.294 ± 0.019) (n = 6); PeL 0.188–0.238 (0.217 ± 0.020) (n = 6); PeD 0.151–0.178 (0.161 ± 0.009) (n = 6); ApL 0.148–0.173 (0.156 ± 0.009) (n = 6); ApW 0.103–0.125 (0.118 ± 0.008) (n = 6); OpL 0.064 (n = 1); OpW 0.061 (n = 1).

Remarks. The gonozooid in Calyssopora vasiformis n. sp. is similar to that in the type species C. volcano n. sp., but the colony surface is malleated, as in Rallocytus ridiculus n. gen., n. sp. (below).

Distribution. Recorded from three stations within coordinates 12.61497– 13.55908° N, 133.04948– 133.18555° W, at depth range 4806–4909 m.

Figures

FIGURE 31. Calyssopora vasiformis n. gen., n. sp. Holotype, ZIRAS 1/50717. A–D, rotational views of fertile colony; E, H, apical and oblique-lateral views of calyx with gonozooid; F, two autozooidal peristomes, with part of dimpled and alveolate calyx surface; G, close-up of calyx in A; I, ooeciostome and ooeciopore; J, close-up of G, with autozooidal peristomes and small alveoli; K, honeycomb-like surface malleation. Scale bars: A–D, G, H, 200 µm; E, F, J, K, 100 µm; I, 25 µm.

FIGURE 32. Calyssopora vasiformis n. gen., n. sp. Stages of colony development. A–D, specimen GLD4–11, Stn 228, at apparent four-zooid stage with large alveoli; E–H, specimen GLD4–11, Stn 201, at a later stage, with more-developed calyx center. Scale bars: 200 µm.