Hippomenella amaralae, Vieira, Leandro M., Gordon, Dennis P., Souza, Facelucia B. C. & Haddad, Maria Angélica, 2010

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 : 22

Hippomenella amaralae n. sp.

( Figures 44–47 , Table 10)

Material examined. Holotype. MZUSP 0 302, Brazil, project REVIZEE South SCORE, RV ‘Prof. Wladimir Besnard’, station 6793 (gold-coated specimen). Paratype. MZUSP 0 303, Brazil, project REVIZEE South SCORE, RV ‘Prof. Wladimir Besnard’, station 6793.

Diagnosis. Colony encrusting, with rectangular to irregularly polygonal autozooids; orifice large with a broad deep poster, paired condyles and 4–5 oral spines; ovicells hyperstomial, large, globular, with radial rows of pores in furrows, not closed by maternal operculum.

Etymology. Named in honour of Dr Antonia Cecilia Z. Amaral (Universidade Estadual de Campinas, Brazil), the coordinator of Benthos of REVIZEE South Score Project.

Description. Colony encrusting, unilaminar. Autozooids rectangular to irregularly polygonal, convex, separated by deep grooves. Frontal shield convex, thick, smooth, with 2–4 rows of evenly distributed pseudopores; central area lightly raised, imperforate with increased calcification. Orifice rounded distally, arched, the poster broad and deep with rounded triangular condyles directed proximomedially. Orifice with 4– 5 distal spines. Adventitious avicularia 1–3, usually paired, close to central area of frontal shield, separated and directed proximally, or proximolateral to orifice and directed laterally; rostrum acute, slightly raised, crossbar thin. Ovicells hyperstomial, large, globular, slightly hummocky with somewhat radial rows of pores in furrows, not closed by maternal operculum; pores minute or becoming obliterated with increased calcification, ovicell then tending to become slightly umbonate; fertile orifice with 2–3 distal oral spines.

n min–max mean SD Autozooid length 7 0.725–0.875 0.779 0.056 Autozooid width 7 0.450–0.580 0.509 0.047 Orifice length 7 0.240–0.255 0.249 0.005 Orifice width 7 0.187–0.220 0.202 0.012 Remarks. Tilbrook (2006, p. 256) commented on the status of some species of Hippomenella in relation to the variable characters of the ovicell ― uniformly perforate in the type species Lepralia mucronelliformis Waters, 1899 , but bifenestrate in some Recent and fossil species. Tilbrook (2006) noted that some species shared other characteristics of primary orifice and frontal wall: the mucronelliformis group, e.g. H. mucronelliformis , H. vellicata ( Hutton, 1873) , H. bituberosa Brown, 1952 and H. avicularis (Livingstone, 1926) , characterized by uniformly perforate ovicells, about six oral spines, a straight or lightly convex proximal rim, and sometimes a small umbo; and the lateralis group, e.g. Hippomenella lateralis ( MacGillivray, 1891) and H. rudicula Tilbrook, 2006 , characterized by bifenestrate ovicells, a primary orifice with a concave proximal rim, more than 10 oral spines, and no frontal umbo. The first recorded species of the genus in Brazil, newly described here as Hippomenella amaralae n. sp., belongs to the mucronelliformis group owing to its non-bifenestrate ovicells and the presence of 4–5 oral spines, but its orifice has a concave proximal rim as in species of the lateralis group.

Distribution. Brazil: off Santa Catarina state, 140 m (present study).

Figures

FIGURES 44 – 47. Hippomenella amaralae n. sp., MZUSP 0 302 (holotype specimen), off São Paulo, Brazil. 44, Colony; 45, close-up of autozooid with ovicell, 46, close-up of autozooid with five oral spines; 47, close-up of orifice with four oral spines.