Alyonushka hystricosa, 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 : 40

Alyonushka hystricosa n. sp.

( Figs 2L , 24 , 25 )

Material examined. Holotype: ZIRAS 1/50711, colony attached to particle of nodule, YMG R.V. Gelendzhik cruise GLD4–09, Stn 199, 7 January 2011, 13.09042° N, 133.55185° W, 4758 m. One specimen only.

Etymology. Latin, hystricosus, prickly, thorny, alluding to the minutely prickled colony surface.

Description. Sole colony erect, pedunculate and subcalyciform, with outwardly flaring capitulum of relatively short autozooidal peristomes ( Fig. 24 ), up to 10 in single irregular whorl. Column narrowest below middle, widening to slightly bulbous base thickened by development of layers of overlapping flattened alveoli/kenozooidlike chambers ( Fig. 25D ). Entire external skeletal surface of colony densely covered by minutely branched tiny prickles except for distal half of peristomes.

Surface of autozooidal peristomes irregularly granular-tubercular, tubercles tending to be slightly elongated and in partly linear series down sides of peristome ( Fig. 25C ). Aperture subcircular to suboval, rim thin, generally facing obliquely outwards. Interior of peristomes smooth or lightly textured, lacking spinulation ( Fig. 25B, C, F ).

Gonozooid occupying calyx center ( Fig. 24A–C ), large, slightly convex, its surface prickled, centrally imperforate, surrounded by irregular alveoli around periphery ( Fig. 24A ). Ooeciostome ( Figs 24A–C , 25A, B, E ), very short, subcircular, with thin prickled rim, inner surface with low irregularities ( Fig. 25A ). Ooeciopore smaller than autozooidal apertures.

Ancestrula and very early colony stages not seen.

Measurements (mm). Holotype, ZIRAS 1/50711 ( Figs 24 , 25 ): Colony height 2.08; capitulum 1.31 × 1.08; base diameter at substratum 0.69; minimum column diameter 0.43; ZL 0.403–0.618 (0.513 ± 0.068) (n = 9); PeL 0.213–0.303 (0.264 ± 0.026) (n = 9); PeD 0.128–0.153 (0.143 ± 0.010) (n = 9); ApL 0.154–0.175 (0.165 ± 0.008) (n = 9); ApW 0.106–0.128 (0.118 ± 0.007) (n = 9); OpD 0.087 (n = 1).

Remarks. Alyonushka hystricosa n. sp. is most readily distinguished from the type species and Alyonushka echinata n. sp. (below) by the smooth, non-spinulose inner surface of zooidal peristomes, as well as the surface appearance of the gonozooid.

Distribution. Recorded from a single station with coordinates 13.09042° N, 133.55185° W, at 4758 m depth.

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 24. Alyonushka hystricosa n. gen., n. sp. A, B, holotype, ZIRAS 1/50711, apical and oblique views of capitulum with gonozooid; C, D, same specimen showing entire colony. Arrows indicate the same ooeciostome in each photo. Scale bars: 250 µm.

FIGURE 25. Alyonushka hystricosa n. gen., n. sp. Holotype, ZIRAS 1/50711. A, ooeciostome; B, calyx margin with autozooidal peristomes, ooeciopore near middle right; C, close-up of peristomes and surface sculpture, ooeciopore at lower right; D, colony base; notice minutely prickled surface; E, oblique view of calyx, ooeciostome to right of center; F, symmetrical alveolus opening between a pair of peristomes. Scale bars: 100 µm.