Leptinatella gordoni, Cook & Bock, 2000

Cook, P. L. & Bock, P. E., 2000, Two new genera of Bryozoa (Calloporidae) from New Zealand, Journal of Natural History 34 (7), pp. 1125-1133 : 1126-1129

Leptinatella gordoni n. sp.

(®gures 1, 2) Watersia militaris: Livingstone, 1929: 53 ; Gordon, 1986: 28, Pl. 3C, D (not W. militaris (Waters) 5 Corbulipora tubulifera (Hincks) see Bock and Cook, 1994).

HOLOTYPE. Colony in collection of the N.Z. Oceanographic Institute, DSIR, Wellington, type number H-612, from NZOI Stn B 498 . PARATYPES, P-952, from the same locality. Other material, NZOI Stn M 7912, see Gordon, 1986 .

Material examined

New Zealand Oceanographi c Institute, Station B 498, 40ss46.3¾S, 174ss02.8¾E, north end of South Island , Jag Rocks, on Pecten shells, 44 m, 11 June 1961. NZOI Station M 791, 44ss37.1¾S, 167ss51.5¾E, south-west of South Island , East Milford Sound, 30 m, 6 April 1981 .

University Zoological Museum , Copenhagen , Denmark. Three Kings Island, north of North Island, 84 m. Collected by T. Mortensen, 1915, and labelled` Marcus ident. veri®ed by A. Livingstone, Sydney, 1927’, on algal frond .

Distribution North and South Island, New Zealand.

Etymology

The species is named for Dr D. P. Gordon ( NZOI) who provided much of the material discussed in this paper.

Description

Leptinatella with autozooids virtually without gymnocyst, which forms a thin margin only; cryptocyst narrow, a little wider proximally; oral spines delicate. Zooids communicating through one or two distal and two or three groups of multiporous pore plates. Brooding zooids not dimorphic; ovicell prominent, globular, with a central suture and a pair of small, proximally placed entooecial areas frontally; not closed by the operculum. Zooids of the earlier astogenetic stages becoming closed by a porous, calci®ed, subfrontal lamina derived from the cryptocyst, leaving a distal, subopercular scar. Avicularia large, interzooidal, with an irregular, lateral gymnocyst, which forms an ill-de®ned pair of condyles, and an acute, slightly asymmetrical rostrum.

Remarks

The holotype colony encrusts a fragment of Pecten shell and includes about 100 zooids, approximately half of which bear ovicells, but has no avicularium present. The paratype colony, part of which was ®gured by Gordon (1986: 28, pl. 3C, D as Watersia militaris ) has both avicularia and closed zooids. These closures resemble those described in the genus Conopeum and in other anascans by Cook (1985). The avicularia seem to occur in areas of crowding. They are slightly asymmetrical, with a subtriangular rostrum. The UZMC specimen listed by Livingstone (1929) from Three Kings Island forms an extensive colony of about 1000 zooids covering the narrow fronds of an alga on both sides. This may be one of the reasons why Livingstone identi®ed it with the erect, ¯ustrine, Watersia militaris . Neither avicularia nor closed zooids are present but ovicells are abundant. They do resemble those of W. militaris , the reproductive phase of Corbulipora tubulifera , quite closely, diOEering principally in the small size and proximal position of the entooecial areas.

Leptinatella gordoni resembles many species of Crassimarginatella in possessing paired oral spines, interzooidal avicularia and hyperstomial ovicells. The ovicell resembles that of C. fraudatrix Gordon (1986: 33 , pl. 6D, E) which was also from Milford Sound, Stn M791; C. fraudatrix has, however, numerous marginal spines and robust calci®cation. Leptinatella diOEers from the Watersia -phase in its encrusting colonies, which are not part of a multiphased cribrimorph species complex, in the form of its avicularia, and in the lack of enlarged spines on the ovicelled zooids. L. gordoni seems to have a fairly extensive distribution in New Zealand, the present records being from north of North Island and south-west of South Island.

Bryocalyx n. gen. Type species: Bryocalyx cinnameus n. sp.

Etymology

The name Bryocalyx was suggested by Dr D. P. Gordon; it is derived from a combination of Bryozoa, and calyx (Greek, kalyxÐ a cup), with reference to the shape of the colony.

Description

Colonies unilaminar, fan-shaped or conical, arising from an elongated ancestrula and anchored by rhizoids. Zooids with an extensive membranous frontal wall, gymnocyst marginal, cryptocyst and marginal spines absent. Ovicells large, with a partially uncalci®ed ectooecium and a thinly calci®ed entooecial capsule. Avicularia absent.

Remarks

Bryocalyx is introduced for B. cinnameus n. sp., of which plentiful material exists. However, Gordon (1985) referred some minute fragments of another unilaminar species from the Kermadec Ridge to Watersia sp. , and ®gured the ovicells (1985: 162, ®gure 2). These two fragments have been re-examined. They consist of nine zooids and ®ve ovicells in total. All zooids and ovicells are unattached, unilaminar, very thinly calci®ed, and somewhat shrunken and distorted. The zooids and ovicells resemble those of B. cinnameus , but are far smaller (see table 1). The inner entooecial capsule is globular, and the ectooecium has paired valves, meeting in a central suture, and each with a large, membrane-covered foramen laterally. The operculum appears to close the ovicell, but this may be an artifact of preservation. The basal walls of some zooids have a distinct keel, and one zooid at the lower end of the larger fragment is budded with its frontal side on the basal surface. This suggests that a conical colony, like that of B. cinnameus , which develops in the same way, may occur later in astogeny in this species.

The fragments are so fragile that further examination is not possible without damage. They were collected by RV Tangaroa at the centre of the Kermadec Ridge (NZOI Stn K839, 30ss15.4¾S, 178ss24.0¾W, 290 m, 29 July 1974). Until further material becomes available for examination, it seems advisable to leave this species of Bryocalyx unnamed at present.