Chaperia brasiliensis, 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 : 6

Chaperia brasiliensis n. sp.

( Figure 2 , Table 2)

Material examined. Holotype. MZUSP 0 274, Brazil, project REVIZEE South SCORE, RV ‘Prof. Wladimir Besnard’, station 6669, gold-coated specimen. Paratype. MZUSP 0 275, Brazil, project REVIZEE South SCORE, RV ‘Prof. Wladimir Besnard’, station 6793 (alcohol 70%).

Diagnosis. Colony unilaminar with quincuncial autozooids; circular opesia with paired occlusor laminae, cryptocyst occupying half zooidal length, 7–11 distal spines; distal end of zooid with three facets with 3–4 pairs of septular pores.

Etymology. The species name alludes to the type locality.

Description. Colony loosely encrusting, unilaminar, multiserial, the available fragments not exceeding 7 mm maximum diameter. Zooids arranged regularly quincuncially, rounded distally, widest midlength, then tapering to a narrow or acutely angled proximal margin. Cryptocyst slightly convex, granular, occupying one third to one half zooid length. Opesia circular or a little wider than long, with a pair of stout occlusor laminae; about 7–11 oral-spine bases distributed around the distal part of the opesia in a shallow arc, the most proximal spine bases more or less adjacent to the distal insertion points of the occlusor laminae. Distal end of each zooid with three facets where each of them joins daughter zooids; each facet with 3–4 pairs of septular pores in parallel vertical rows. Ancestrula not seen. Avicularia absent. Ooecia absent.

n min–max mean SD Autozooid length 8 0.346–0.506 0.424 0.047 Autozooid width 8 0.340–0.469 0.411 0.046 Opesia length 8 0.216–0.259 0.236 0.015 Opesia width 8 0.247–0.290 0.265 0.015 Remarks. Chaperia brasiliensis n. sp. is only the second species of the genus to be recorded in Brazilian waters. Ten Recent species of Chaperia Jullien, 1881 are known, mainly from the southern hemisphere. The nominal type species, Chaperia australis Jullien, 1881 , is generally considered to be a junior subjective synonym of Flustra acanthina Lamouroux, 1824 [see Hayward and Cook (1983) for nomenclatural history]. Marcus (1955) reported and illustrated a species from south of Vitória, Espírito Santo state, which he attributed to C. acanthina , but his material had four distal spines and a pair of proximolateral spines and thus cannot belong to this species; C. acanthina from the type locality [Falkland ( Malvinas) Islands] has six distal spines and no proximal ones ( Gordon 1986). Thus, the material recorded by Marcus (1955) as C. acanthina represents a new, undescribed species. The only other geographically close congeners are Chaperia capensis ( Busk, 1884) , Chaperia polygonia Kluge, 1914 , and Chaperia septispina Florence, Hayward & Gibbons, 2007 , all from South Africa. Chaperia capensis has only two distal spines, C. polygonia five or six, and C. septispina seven spines.

Our specimens of C. brasiliensis are of non-attached transported fragments and hence slightly eroded, which renders the precise number of spine bases uncertain. Judging from the convex shapes of the specimens, with down-curving edges, they appear to have been growing on a non-durable substratum ― perhaps a sponge or ascidian, which was partly overgrown by another bryozoan that was in turn overgrown by C. brasiliensis .

Distribution. Brazil: off São Paulo and Santa Catarina states, 101–140 m (present study).

Figures

FIGURES 2 – 7. 2, Chaperia brasiliensis n. sp., MZUSP 0 274 (holotype specimen), off São Paulo, Brazil. 3 – 7, Amastigia aviculifera n. sp., MZUSP 0 276 (part of holotype specimen), off São Paulo, Brazil. 3, Frontal view of multiserial branch; 4, close-up of paired avicularia at the distal end of the ovicell and one ovicelled zooid; 5, close-up of triserial branch with large frontal avicularia; 6, close-up of biserial branch, note the presence of six distal spines and large proximal avicularium; 7, close-up of two basal vibracula.