Beania americana Vieira, Migotto & Winston, 2010, n. sp.

Beania americana n. sp.

(Figs 14, 15, 24; Table 2)

Beania hirtissima: Marcus 1937: 62, pl. 14, fig. 31; 1941: 19, fig. 12; Osburn 1940: 397; Lagaaij 1963: 180, pl. 8, fig. 4; Maturo 1966: 579, fig. 17; Winston 1982: 131, fig. 56; Vieira et al. 2008: 17 (checklist). Non Diachoris hirtissima Heller, 1867.

Material examined. Holotype: MZUSP 415. Paratype: MZUSP 416, Additional material: Marcus collection (19), Beania hirtissima E. Marcus det. on rocks; MZUSP 417–428; VMNH 760.00, Beania hirtissima, Walton Rocks, South Hutchinson Island, St Lucie County, Florida, USA, coll. J. E. Winston, 28.xi, 1998, intertidal beach rock; VMNH 2612.00, Beania hirtissima, Juno Ledge, off Palm Beach, Florida, USA, coll. Littler and Little, 18.vii.1999, drift dive, 20 m, on alga; VMNH 3150.01, Beania hirtissima, North Beach, Fort Pierce, St Lucie County, Florida, USA, coll. J. E. Winston 21.vi.2003, beach drift alga, with B. mirabilis (= B. mirabilissima).

Description. Colony reticulate, semierect, grayish-brown in color, often heavily coated with mud and debris. Zooids with lightly calcified curving lateral and basal walls and a membranous frontal surface; zooids joined by 6 tubular processes and attached loosely to substratum by tubular radicles. Frontal surface constricted into two parts, a smaller oval opercular area surrounded by a halo of 8–10 long, straight stout spines, and a larger oval proximal region with 9–13 pairs of spines arched over the frontal membrane plus some projecting outward from the lateral walls. Tubular radicles extend from the proximal portion of zooids. Avicularia and ovicells absent.

Remarks. Beania hirtissima has been considered to have a worldwide geographical distribution in shallow, warm-temperate to tropical seas (Winston 1982; Cook 1985; Hayward & McKinney 2002). Hayward and McKinney (2002) examined the type of Beania hirtissima (Heller, 1867) and designated its lectotype, a specimen with vicarious avicularia, autozooids 0.8–1.0 mm long with seven stout spines surrounding the operculum like a halo (three distal and two on each side), and only five erect spines on each lateral margin of the frontal membrane, each with a shorter spine at its base, curving medially over the frontal membrane. They remarked that records of Beania hirtissima should “be reexamined in light of the characteristics of the lectotype ”. They examined one such taxon with reticulate colonies that had often been attributed to Beania hirtissima f. or var. cylindrica, and designated it as Beania cylindrica (Hincks, 1886). Cook (1985) showed that B. hirtissima may represent a species complex and, more recently, Tilbrook (2006) noted that some reports previously attributed to this species represent undescribed species.

Beania cylindrica (Hincks, 1886) has bigger autozooids (1.0 x 0.25 mm), a terminal operculum orientated perpendicular to the frontal membrane, only six distolateral spines and another 8–10 pairs of slightly incurved lateral spines. In the erect tufts of Beania cylindrica, each autozooid is linked to six neighbors by tubular connections, three proximal and closely spaced and the other three mid-basal. In contrast, colonies of B. hirtissima are unilaminar sheets with autozooids closely spaced and linked by a ring of six short connecting tubes around their proximal ends.

Marcus (1937) characterized colonies of Beania hirtissima from Santos (São Paulo state, Brazil) as having a distal halo of 10 long spines and 12 pairs of shorter lateral spines; additionally, he described some basal spines, sometimes bi- or trifurcated. We consider that Beania hirtissima sensu Marcus (1937, 1941) is a previously undescribed species, named herein as Beania americana n. sp.

Although B. americana is similar to the lectotype of B. hirtissima in the general habit of the colony and characters of the autozooid, it is clearly distinguishable, particularly by the number and size of spines and size of zooids (see Table 2). Shared features of the Brazilian and Western Atlantic colonies also led us to reassign some specimens previously recorded as Beania hirtissima (viz. Osburn 1940; Lagaaij 1963; Maturo 1966; Winston 1982) to B. americana.

measurements from Hayward and McKinney (2002). MA, distance between midpoints of adjacent apertures. Mean (St Dev) 0.503 (0.054) 0.508 (0.030) 0.521 (0.036) 0.499 (0.065) 0.549 (0.092)

Min–Max 0.385–0.615 0.462–0.569 0.440–0.600 0.394–0.600 0.377–0.792 Beania americana and B. cylindrica are similar in the number of spines arched over the frontal membrane, but B. americana differs in having smaller zooids (reaching 0.723 x 0.338 mm), a halo of 8–10 stout distal spines, and autozooids linked to six neighbors by long, well-spaced tubular connections. The other similar Brazilian species, described herein as Beania correiae n. sp., is readily distinguished by the number of marginal spines arched over the frontal membrane.

Biological notes. Beania americana was found on rocky shores from the intertidal to 20 m deep on rocks, macroalgae including red algae and Sargassum sp., and other bryozoans [viz. Amathia spp. and Anguinella palmata]; it was also present on shallow soft bottoms (6–10 m) on rocks and shell fragments (Table 6). In Florida (USA), it was found year-round, epibiotic on hydroids and encrusting beach rocks partially buried in sand (Winston 1982). Colonies are also utilized as a substratum by other cheilostome bryozoans. Colonies coated with sediment can hardly be seen in situ.

Distribution. Atlantic. Brazil: Paraná (Marcus 1941; present study), São Paulo (Marcus 1937; present study) and Alagoas (present study); Porto Rico and Bermuda (Osburn 1940); USA: North Carolina, Georgia (Maturo 1966), Florida (Maturo 1966; Winston 1982; present study) and Gulf of Mexico (Lagaaij 1963).