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 : 1126-1128

Leptinatella gordoni n. sp.

(figures 1, 2)

Watersia militaris: Livingstone, 1929: 53 ; Gordon, 1986: 28, Pl. 3C, D (not W. militaris (Waters) = 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 B498 . PARATYPES, P-952 , from the same locality . Other material, NZOI Stn M7912, see Gordon, 1986 .

Material examined

New Zealand Oceanographi c Institute, Station B498 , 40°46.3'S, 174°02.8'E, north end of South Island , Jag Rocks, on Pecten shells, 44 m, 11 June 1961. NZOI Station M791 , 44°37.1'S, 167°51.5'E, 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 fi 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 fi 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 fi 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 fi 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 fi ed it with the erect, fl 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, differing 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 fi cation. Leptinatella differs 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.