Paracellaria elizabethae, Branch & Hayward, 2005

Branch, M. L. & Hayward, P. J., 2005, New species of cheilostomatous Bryozoa from subantarctic Marion and Prince Edward Islands, Journal of Natural History 39 (29), pp. 2671-2704 : 2680-2682

Paracellaria elizabethae sp. nov.

( Figure 5 A–D)

Material

Holotype: St. 42 Marion Island (46 ° 40 9 S, 37 ° 51 9 E), 460–560 m, SAM A27537 . Paratype: St. 39 Marion Island (46 ° 60 9 S, 38 ° 01 9 E), 360–376 m, SAM A27538 .

Other material. St. 45 Marion Island (47 ° 00 9 S, 37 ° 55 9 E), 420–540 m, SAM A27092 .

Description

Colony delicate, translucent, branching dichotomously at frequent and regular intervals, each new ramus separated from the preceding internode by a fracture joint and secured by chitinous rhizoids; up to about 30 mm, internodes usually less than 5 mm long and 0.5 mm wide. Autozooids disposed in alternating whorls of three; elongate hexagonal, separated by thin raised ridges; 0.55–0.70X 0.40–0.45 mm. Opesia situated close to the distal border of the autozooid, comprising ca one-tenth of total autozooid length; semicircular, slightly wider than long, 0.1X 0.09 mm, with raised, thickened rim; a short, thick denticle visible in each proximo-lateral corner. Cryptocyst concave, smooth medially, grading to finely granular; a pair of curving cryptocystal ridges, with distinctly crenulated edges, extend for ca two-thirds of autozooid length, from adjacent to the opesia, where they are raised and prominent. Avicularia interzooidal, smaller than autozooids, triangular to diamond shaped, with narrow triangular rostrum, 0.1 mm long, directed disto-lateral to the axis of the internode.

Etymology

Named for the first author’s mother-in-law, Elizabeth Branch.

Remarks

Paracellaria elizabethae sp. nov. is especially characterized by its short, wide opesia, and the disto-lateral orientation of the avicularium, features particularly important in distinguishing species of this genus. Paracellaria is presently constituted by the endemic Antarctic type species, P. aeandeli (Calvet, 1909) , by the subantarctic P. calυeti ( d’Hondt, 1984) and P. elephantina ( Hayward and Thorpe, 1989) , and by P. cellarioides ( Hayward and Thorpe, 1989) , which is known from the southern Patagonian shelf. Raised cryptocystal ridges are seen in all of the latter three species. Paracellaria cellarioides differs from P. elizabethae sp. nov. in its distally directed avicularia and elongate opesia, and in the arrangement of autozooids, in spiral whorls of eight. In P. calυeti autozooids are arranged in whorls of four, the opesia is proportionately shorter and broader than that of P. elizabethae sp. nov., and the projecting distal portions of the crytocystal ridges meet and fuse medially. Paracellaria elephantina , finally, has proximo-laterally orientated avicularia, and an opesia that is much longer than wide.

Figures

Figure 5. Paracellaria elizabethae sp. nov., SAM A27537: (A) autozooids and large avicularia, X80; (B) autozooid with, distally, the aperture of an endotoichal ovicell, X120; (C) avicularium, X280; (D) colony, X3.