Fenestrulina ampla Canu & Bassler, 1928a

Vieira, Leandro M., Gordon, Dennis P., Souza, Facelucia B. C. & Haddad, Maria Angélica, 2010, New and little-known cheilostomatous Bryozoa from the south and southeastern Brazilian continental shelf and slope, Zootaxa 2722, pp. 1-53 : 26-27

Fenestrulina ampla Canu & Bassler, 1928a

( Figures 58–63 , Table 12)

Fenestrulina ampla Canu & Bassler, 1928a: 84 , pl. 6, figs. 5–6; Vieira et al., 2008: 30 (checklist).

Material examined. MZUSP 0 308, Brazil, project REVIZEE South SCORE, RV ‘Prof. Wladimir Besnard’, station 6661. MZUSP 0 309, station 6661. MZUSP 0310–311, station 6678. Comparative material. Fenestrulina ampla Canu & Bassler , USNM 8560 (holotype specimen, figs 58–60), 21º48’S 40º3’ W, off Rio de Janeiro, Brazil, 128 m.

Redescription. Colony encrusting, calcified, unilaminar, flat in later ontogeny. Autozooids hexagonal to oblong, convex, separated by distinct grooves. Frontal shield smooth, convex, with irregularly distributed stellate pores, absent below ascopore; pores mostly present between orifice and ascopore and at the border of the zoecium; ascopore small, crescentic, denticulate, slightly raised and situated slightly distal to middle point of zooid. Primary orifice large, D-shaped, wider than long; 3 small oral spines in non-ovicelled zooids; ovicelled zooids with 2 oral spines. Ovicell subglobular, large, closed by maternal operculum; frontal surface flat with some frontal ridges, conspicuous at midpoint in later ontogeny; inconspicuous basal pores.

n min–max mean SD Autozooid length 10 0.596–0.739 0.687 0.051 Autozooid width 10 0.457–0.700 0.491 0.092 Orifice length 10 0.135–0.170 0.149 0.012 Orifice width 10 0.188–0.243 0.202 0.019 Ovicell length 4 0.370–0.416 0.397 0.022 Ovicell width 4 0.374–0.415 0.402 0.018 Remarks. Fenestrulina ampla was originally described from off Rio de Janeiro by Canu & Bassler (1928a) (holotype USNM 8560, 21º48’S 40º3’ W, 128 m), and was characterized by large zooids and a frontal shield with some large stellate pores. Some colonies from REVIZEE samples were found on Aulopocella americana n. sp. (MZUSP 0308) with other bryozoans, such as Smittina migottoi n. sp. and Arachnopusia spp. Fenestrulina majuscula Hayward, 1980 from the Falkland Islands is also characterized by large zooids with several large frontal pores, but the pores in this species are closer together than those found in F. ampla . Hayward and Ryland (1990) also described a distinct elongate mural pore chamber with multiporous septula in each lateral wall of F. m a j u s c u l a, which is not the case in F. a m p l a. Fenestrulina majuscula also differs from F. ampla in having two distal spines.

Hayward and Ryland (1990) recorded and desribed some new and little-known species of Fenestrulina Jullien, 1888 from Antarctic and subantarctic South Atlantic waters. These species are distinguished from Brazilian F. ampla by presence/absence and number of oral spines. Fenestrulina amplissima Hayward, 1980 , F. cervicornis Hayward & Ryland, 1990 , F. d i c t y o t a Hayward & Ryland, 1990, F. dupla Hayward & Ryland, 1990 and F. horrida Moyano, 1985 have four oral spines. Two species, F. exigua ( Waters, 1904) and F. proxima ( Waters, 1904) , have six oral spines, and only F. marioni Hayward & Ryland, 1990 has five. Four species have zooids without oral spines, viz. F. fritilla Hayward & Ryland, 1990 , F. crystallina Hayward & Ryland, 1990 , F. i n c u s a Hayward & Ryland, 1990 and F. jucunda Hayward & Ryland, 1990 ; only two, F. rugula Hayward & Ryland, 1990 and F. m a j u s c u l a, have a single pair. Fenestrulina ampla is characterized by the presence of three oral spines in non-ovicelled zooids and two in ovicelled zooids.

Distribution. Brazil: off Rio de Janeiro ( Canu & Bassler 1928a) and São Paulo states (present study), 99– 147 m.

Figures

FIGURES 58 – 63. Fenestrulina ampla Canu & Bassler, 1928 a. 58 – 60, USNM 8560 (holotype specimen of Fenestrulina ampla), Rio de Janeiro, Brazil. 58 – 59, Colony with autozooids and one ovicelled zooid; 60, close-up of orifice with three oral spines. 61 – 63, MZUSP 0 308 (part of specimen), off São Paulo, Brazil. 61, Colony; 62, close-up of ovicelled zooid; 63, close-up of autozooid.