Filifascigera brevicaudex, Gordon & Taylor, 2010

Gordon, Dennis P. & Taylor, Paul D., 2010, New seamount- and ridge-associated cyclostome Bryozoa from New Zealand, Zootaxa 2533 (1), pp. 43-68 : 53

Filifascigera brevicaudex n. sp.

( Fig. 6 A–C )

Material examined. Holotype: NIWA 61246 , from NIWA Stn I 97, 32°23.29’ S, 167°28.20’ E, West Norfolk Ridge , 540–544 m depth, collected 25 July 1975 . Paratype: NIWA 61247 , from KAH0204/15, 34°05.98– 34°06.21’ S, 174°06.82– 174°06.91’ E, Cavalli Seamount , 470–480 m depth, collected 15 April 2002. Other stations: Cruise KAH0204, Stns 1, 8, 9, 21, 22, 28, 32, 34, 40, 47, 50, Cavalli Seamounts, off northeastern North Island .

Distribution. From Cavalli Seamounts off northeastern North Island and West Norfolk Ridge, 470–930 m depth.

Etymology. Latin, brevis, short + caudex, stem, trunk, alluding to the short, erect fascicles of zooids.

Description. Mature colony comprising ramifying and occasionally anastomosing branches from which arise relatively short fascicles of zooids; spread of colony about 5 cm. Width of ramifying branches 0.67–0.90 mm, these containing 5–11 zooidal cross sections in profile, 3–6 zooids having their basal wall against the substratum. Fascicles arising at intervals of about 1.5–3.5 mm from each other depending on the irregularity of the substratum, about 0.6–2.2 mm high and 0.78–0.87 mm in diameter, with about 7–11 peristomes occurring in a cluster at the flattish summit; a few other peristomes opening at intervals on the stem. Peristome diameter 0.13–0.16 mm, whether in ramifying or erect portions of colony. Gonozooid borne at the top of an erect fascicle, brood chamber ventricose, 0.84 mm in diameter, the ooeciostome subcircular, 0.15 mm diameter.

Ancestrula not seen but immediate post-ancestrular zooids preserved in one colony; branch width rapidly increases to incorporate several zooids adnate to the substratum before the first fascicle is produced; a branch bifurcation occurs near the base of the fascicle and all subsequent branching is generally of this nature except that not all fascicles are succeeded by a bifurcation.

Remarks. Relatively few species of Filifascigera have been described. The type species is from the Paleocene of New Jersey. Canu & Bassler (1929) attributed six other species to the genus, ranging in stratigraphic distribution from the Cretaceous to the present day. Osburn (1953) recognised two more Recent species, and Brood (1972) and Taylor & McKinney (2006) have named additional Cretaceous species. Of the five putative Recent species, nominally from Ireland, the Pacific coast of America, Hawaii and the Philippines, F. brevicaudex differs from them particularly in the dimensions of the fascicles and numbers of peristomes in each fascicle. The two Philippines species illustrated by Canu & Bassler (1929) have no peristomes emerging from the stem of the fascicle. In F. clarionensis from California, the brood chamber occurs between a close pair of fascicles, extending from one fascicle to the next ( Osburn 1953).

Figures

FIGURE 6. Filifascigera brevicaudex n. sp. (NZOI Stn I97). A, part of holotype colony in frontal view showing an adnate branch with fascicles; B, profile of two fascicles; C, fascicle with brood chamber.