Supercytis savii, Ramalho, Muricy & Taylor, 2009

Ramalho, L. V., Muricy, G. & Taylor, P. D., 2009, Cyclostomata (Bryozoa, Stenolaemata) from Rio de Janeiro State, Brazil, Zootaxa 2057, pp. 32-52 : 44-47

Supercytis savii sp. nov.

( Figs 3E, 8A–F)

Material examined. Type material. MNRJ-187 (holotype), MNRJ-242 (paratype), Região dos Lagos, 23°47.629’S, 041°42.514’W, 20 July 2004, collector D.C. Savi, depth 341 m.

Diagnosis. Colony small, white, erect, with bifurcating branches arising from colony centre; autozooids on branches with alternating acute apertures lacking or with very short exterior frontal walls. Gonozooid wider than long, located at bifurcation, enveloping a few autozooids; ooeciopore flattened, wider than long, ooeciostome short.

Description. Colony small, white, arising from encrusting base and thick peduncle, elevating branches above substratum; 7 bifurcating branches diverging from colony centre ( Fig. 8A–B). Branch dorsal surfaces comprising exterior walls with small pseudopores and longitudinal striations. Autozooids alternately disposed along branches, opening at an acute angle on frontal surface with aperture almost circular, exterior frontal wall lacking or very short ( Fig. 8C); colony centre formed by tubular zooids with polygonal apertures ( Fig. 8B–D). Intramural spinules palm-shaped with several sharp, finger-like spinelets ( Fig. 8E), varying from one to several per zooid, occurring both in centre of colony and on branches. Wall microstructure of flattened, irregular shaped crystallites without regular orientation ( Fig. 8F). Gonozooid wider than long (680 µm long x 846 µm wide), inflated, located at branch bifurcation, enveloping a few autozooids. Surface with numerous small pseudopores. Ooeciopore flattened, wider than long (64 µ long x 180 µ wide) with short ooeciostome ( Fig. 3E).

Etymology. Named in honour of David C. Savi who collected this species.

Remarks. Taylor and Grischenko (1999) reviewed the taxonomy of fungiform cyclostomes, providing a key to the 17 fossil and Recent genera developing this colony-form. The new Brazilian species is best accommodated within Supercytis d’Orbigny, 1853 , in which the stalk is formed of exterior wall, the head comprises radial fascicles, and the gonozooid is simple. There is a close similarity between S. savii sp. nov. and S. tubigera Busk, 1886 from the Kerguelen Plateau. The autozooids in Busk’s species, however, have long exterior frontal walls and appear to lack the palm-shaped intramural spinules seen in S. savii sp. nov.

This is the first record of Supercytis from the south Atlantic, extending the nominal distributional range of the genus in Recent seas (it has a Cretaceous type species) which was previously recorded from the southern Indian Ocean (Kerguelen Plateau).

Ecology. Colonies were collected on calcareous rock at 341 m deep.

Geographic distribution. Região dos Lagos (23°47.629’S, 041°42.514’W), Rio de Janeiro State (present study) .