Costaticella peltata Gordon, 1993

Matsuyama, Kei, Janssen, Annika, Arbizu, Pedro Martínez, Martha, Silviu O. & Freiwald, André, 2014, Bryozoans from RV Sonne deep-sea cruises SO 167 ‘ Louisville’ and SO 205 ‘ Mangan’, Zootaxa 3856 (1), pp. 100-116 : 109-111

Costaticella peltata Gordon, 1993

( Fig. 6 , F–K)

Material examined. SMF 15006, SO 167 Stn 32, 22.35983° S – 22.35967° S, 176.09017° W – 176.09350°W, South Tonga Volcanic Arc, 485–651 m, collected 19 October 2002. Not bleached.

Description. Colony erect, dichotomously branching ( Fig. 6 , F). Main colony axis of bizooidal segments only, except for rooted zooids. Zooids elongated with extensive costal shield of 23–30 spines ( Fig. 6 , G), each spine with an infracostal window at its proximal end; fusion point without a median carina in zooidal midline. Basal surface smooth ( Fig. 6 , H). Rooted zooids have two rhizoids, protruding from pores proximal to the lateral pore chambers ( Fig. 6 , I). Orifice subcircular, proximal margin straight; condyles barely visible. At distolateral corners of unizooidal segments a broad scapular process with a tiny avicularium with complete cross-bar, flanked by a porechamber on each side distally and laterally, each as large as the avicularium ( Fig. 6 , J). In bizooidal segments one of the scapular processes of the proximal zooid is replaced by the second zooid. An additional oval pore-chamber on each side in the proximal half of each zooid; a daughter zooid may bud from this pore-chamber ( Fig. 6 , K), its joint of greater diameter than the distal joint separating each segment in the main axis. Fertile segment not known. Measurements. See Table 1.

Remarks. The samples examined are very similar to C. peltata , differing only in their more slender appearance and lack of the spine-like processes mentioned by Gordon (1993).

length width orifice length orifice width

bizooidal proximal mean 808 353 154 151 N = 8 σ 69 22 17 13

min 706 326 131 127

max 910 390 178 166 bizooidal distal mean 749 299 150 147 N = 7 σ 73 17 12 10

min 625 274 132 129

max 821 328 171 160 unizooidal mean 765 311 149 128 N = 2 σ 33 16 1 3

min 732 295 148 125

max 797 326 150 131

Figures

FIGURE 6. A – E, Raxifabia oligopora n. sp. A, frontal view of stem fragment. B, single zooid in frontal view. C, lateral view of stem fragment. D, single zooid and parts of neighbours in lateral view. E, peristomial orifice and paired distal avicularian chambers. F – K, Costaticella peltata Gordon, 1993. F, frontal view of colony fragment. G, close-up of a bizooidal segment, with the second one replacing the avicularian scapular process. H, dorsal view of a bizooidal segment. I, zooid with paired proximal rhizoids. J, distolateral scapular process with avicularium flanked by a pair of pore-chambers. K, second zooid of a bizooidal segment with a daughter bud from a proximolateral pore-chamber. Scale bars: A, F, 1 mm; B, D, J, 100 Μm; C, G – I, K, 300 Μm; E, 30 Μm.