Cellaria major, Achilleos & Gordon & Smith, 2020

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 : 211-213

Cellaria major n. sp.

( Fig. 6 )

Cellaria sp. 11: Achilleos et al. 2019: [4–8].

Material examined. Holotype: NIWA 128676 , Stn U 595, 30.3583° S, 173.1450° E, 1474 m, Three Kings Ridge NNE of Tui Seamount, collected 7 February 1988 . Paratype: NIWA 144879 , same data as holotype .

Etymology. Latin major , greater, alluding to the large zooid size.

Diagnosis. Colony branching not seen. Autozooids in whorls of 4–6. Opesia as wide as long, D-shaped with smooth rim; proximal rim with small condyles. Small interzooidal avicularia somewhat immersed, with semicircular rostrum, arched frontalwards; wide transversely narrow opesial foramen. Ooecia unknown.

Description. Colony erect; three small internode fragments, each not> 4 mm in length. Stem large, more or less cylindrical (W, 0.924 –1.827 mm), with 4–6 zooidal chambers in cross section.

Autozooids more or less elongate-hexagonal, longer than wide (ZL, 929–1320 μm; ZW, 618–808 μm; ratio 1.4). Cryptocyst concave, finely granular, highest at the zooidal margins with no cryptocystal ridges. Opesia almost as wide as long (OpL, 176–311 μm; OpW, 215–373 μm, ratio 0.8), more or less transversely D-shaped, with smooth little-raised edge, the proximal rim straight with small, mounded condyles. Space between opesia and distal zooid margin.

Avicularia small, interzooidal, distal to parent zooid, somewhat immersed; cystid about the same size as autozooidal opesia, hemispherical or rounded-oblong, densely granular. Rostrum directed distally, semicircular, arched frontalwards, edge weakly scalloped; rostral foramen transversely elliptical. Mandibular pivots horizontal, converging, sometimes touching; if touching, the avicularian opesia separate, smaller than rostral foramen, transversely narrow; cryptocyst dipping inwards (downwards), mostly concealed by shelf edge of cystid (AvCL, 231–310 μm; AvCW, 332–374 μm; ATL, 149–114 μm; ATW, 78–92 μm; RL, 81–92 μm; RW, 78–92 μm).

Ooecia not seen. Most autozooids have a small foramen distal to opesia that may be the locus of a future ooecium.

Ancestrula not seen.

Remarks. The zooids of C. major n. sp. are conspicuously large and can be seen with the naked eye. The interzooidal avicularium with semicircular rostrum somewhat resembles that in several other species, especially Cellaria australis MacGillivray, 1880 from Australia. The autozooids in C. australis , however, are more elongate and almost parallel-sided with a bean-shaped opesia ( Bock 2019) and the cryptocyst is coarsely granular with straight cryptocystal ridges. Also, the proximal rim of the opesia in C. major n. sp. is straight instead of convex like in C. australis .

European Cellaria fistulosa ( Linnaeus, 1758) , near-identical Cellaria parafistulosa d’Hondt & Gordon, 1999 from New Caledonia and Cellaria novanglia Winston & Hayward, 2012 from New England have similar inwarddipping avicularia, but these species have thinner mandibular pivots and autozooidal characters are significantly different (inter alia, a more fusiform shape and knob-like condyles).

Distribution. Three Kings Ridge, 1474 m depth.

Figures

FIGURE 6. Cellaria major n. sp., NIWA Stn U595. A. Autozooids and avicularium. B. Close up of part of (A). C. Opesia with blunt condyles. D. Close up of an avicularium. Scale bars: A, 500 μm; B, 250 μm; C, D 150 μm.