Cellaria, Ellis & Solander, 1786

Achilleos, Katerina, Gordon, Dennis P. & Smith, Abigail M., 2020, Cellaria (Bryozoa, Cheilostomata) from the deep: new species from the southern Zealandian region, Zootaxa 4801 (2), pp. 201-236 : 219-220

Cellaria sp. 3

( Fig. 11 )

Cellaria sp. 3: Achilleos et al. 2019: [4–7].

Material examined. NIWA 132737 , NIWA Stn U 582, 31.8617º S, 172.4333º E, Three Kings Ridge, 790 m, collected 5 February 1988 .

Description. Colony erect, comprising three stems not> 7 mm in length, very slender, 4-sided, tapering proximally (W, 147–399 μm). Zooids arranged back to back in alternating pairs, hence 4 longitudinal series.

Autozooidal cystids highly elongate-hexagonal, sometimes with rounded distal margins and lateral walls of whorled zooid pairs abutting or not (ZL, 632–880 μm; ZW, 343–364 μm; ratio 2). Cryptocystal surface evenly granular except for area proximal to opesia where granules are sparse to absent; cryptocystal ridges unusually merging into lateral zooid margins distally, continuous and rounded proximally. Lowest part of frontal cryptocyst immediately proximal to opesia. Opesia wider than long (OpL, 109–117 μm; OpW, 142–158 μm; ratio 0.75), rim scarcely raised, smooth or weakly and irregularly beaded where granules occur, centre of proximal margin upturned as conspicuous proximal rectangular lip with opesiular indentations either side; no visible condyles.

Avicularia and ovicells not seen.

Presumed ancestrular zooid flanked by larger latero-abfrontal pair, all three tapering to narrow point with tiny rootlet pores. Up to 4 paired zooid whorls distal to ancestrula with paired foramina where opesiular indentations used to be; proximal to these foramina, whorls closest to ancestrula have partial overgrowth of calcification, creating large opening for rootlet. Closure of opesia initiated when median tongue of calcification grows from distal margin to the rectangular lip process.

Remarks. Few species have such a prominent rectangular median process. Liu & Hu (1991) depict a fairly well-developed such process in Antarctic Cellaria complanata , but this species has flanking condyles and many more longitudinal zooidal series. What is striking about the rectangular lip process in Cellaria sp. 3 is how angular it is, even slightly alate, whereas the median convexity of many Cellaria species is typically a rounded convexity. One exception is Cellaria obliquidens d’Hondt & Gordon, 1999 from New Caledonia, but this species has many longitudinal zooidal series and condyle-like processes extend obliquely from the corners of the median process. Also, the distal rim opesial rim in C. obliquidens is straight with weak granulation. Cellaria oraneae Almeida, Souza & Vieira, 2018 from Brazil has such a prominent median process but only related to the ooecial opening, not the opesia.

The slender proximal end of the stem and the rootlets originating distally of the ancestrula observed in this species, resembles Cellaria sp. collected by Hayward (1981, fig. 1B) off South Africa. However, there is not enough information about the species collected by Hayward (1981) to adequately compare the two specimens.

Cellaria sp. 3 co-occurs at the same station locality as Cellaria sp. 1.

Distribution. Three Kings Ridge, 790 m depth.

Figures

FIGURE 11. Cellaria sp. 3, NIWA Stn U582. A. Proximal end of long unbranched stem showing zooids with modified opesiae (mostly occluded) and cowled cryptocysts from which rootlets would proceed in life. B. Proximal end of stem, the smaller zooid at lower left possibly the ancestrula. C. Close up of part of (A), showing occluded opesiae and rootlet loci. D. Proximal part of an internode; the ancestrula faces toward the lower right. E. Part of (A), showing zooidal opesiae becoming occluded by calcified tongue developing from distal rim towards rectangular median process. F. Younger stem with non-occluded opesiae (distal one broken). G. Opesia with proximal rectangular lip. Scale bars: A, 50 μm; B, G, 250 μm; C, E, 200 μm; D, 500 μm; F, 100 μm.