Conescharellina cookae, 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 : 41-42

Conescharellina cookae n. sp.

( Figures 98–103 )

Material examined. Holotype. MZUSP 0 366, Brazil, project REVIZEE South SCORE, RV ‘Prof. Wladimir Besnard’, station 6693. Paratypes. MZUSP 0 367, Brazil, project REVIZEE South SCORE, RV ‘Prof. Wladimir Besnard’, station 6693. MZUSP 0430–453, station 6693. Additional material. MZUSP 0 368, Brazil, project REVIZEE South SCORE, RV ‘Prof. Wladimir Besnard’, station 6664 (alcohol 70%). MZUSP 0 369, station 6675. MZUSP 0 370, station 6693.

Diagnosis. Colony regularly conical; narrow apical end rounded, with several dense clusters of small pores; antapical end roughly planar or slightly convex, usually circular in overall outline or somewhat oval owing to lateral flattening.

Etymology. Conescharellina cookae n. sp. honours bryozoologist Patricia L. Cook (Cookie), in recognition of her many studies on conescharellinids and other bryozoans of similar colony form.

Description. Colony more or less regularly conical, up to 6.2 mm long and 5.0 mm widest diameter. Zooids in about half to two-thirds of colony length with open orifices, the remainder occluded by calcification; orifices arranged roughly quincuncially such as not to be in regular longitudinal or diagonal rows. The narrow apical end rounded, with several dense clusters of small irregular pores, each cluster marking the origination of kenozooidal rhizoids in life. Between and around the rhizoid pores are scattered tiny areolar-septular pores and small circular avicularia , each with a crossbar with ligula. Antapical end of colony roughly planar or slightly convex, generally more or less circular in overall outline or somewhat oval owing to lateral flattening; with radial convexities associated with each autozooid, the surface calcification perforated with abundant areolar-septular pores and scattered tiny round avicularia . Edge of antapical surface irregular owing to projecting zooidal peristomes, each with a single median umbo with a tiny apical avicularium like those elsewhere over the colony and typically 1–3 additional such avicularia embedded in the rim; inner face of peristome beneath apical avicularium flattened or with a short descending ridge. Primary orifice concealed at bottom of peristome; transversely oval with a nearly straight, broad, proximal margin; operculum flat with a thin sclerite around its entire margin to the position of the small proximolateral condyles of the orifice; an occlusor muscle insertion on each side distolaterally. Relatively large circular avicularia present, the crossbar with columella, rare or occasional depending on colony. Ovicell visible as a bulge on the apical side of the orifice, the ectooecium mostly concealed by secondary calcification like that of the zooidal surface, but the proximal part of it visible to the inside of the peristomial rim that crosses it, its surface smooth, opening just above the primary orifice; generally a pair of small round avicularia in that part of the peristome that crosses the ovicell.

Remarks. This and the following species co-occur in the same assemblages, although, judging from our samples, C. cookae is four times more abundant that Conescharellina bocki n. sp. The two species are easy to tell apart ― C. bocki has longer, more tubular peristomes and the antapical end is concave owing to the way the autozooids are budded. Overall, zooidal peristomes are less symmetrical and ovicells less obvious in C. bocki .

Distribution. Brazil: off São Paulo and Santa Catarina states, 430–517 m (present study).

Figures

FIGURES 98 – 103. Conescharellina cookae n. sp., off São Paulo, Brazil (REVIZEE station 6693). 98, Colony; 99, antapical end of colony. 100 – 103, specimen from type locality. 100, Apical end of colony, note the porous areas; 101, close-up of orifice with some peristomial avicularia; 102, close-up of orifice; 103, close-up of avicularium.