Bryopesanser thricyng, Tilbrook, Kevin J., 2012

Tilbrook, Kevin J., 2012, Review of the bryozoan genus Bryopesanser Tilbrook, 2006 (Escharinidae: Cheilostomata) with the description of 11 new species, Zootaxa 3165, pp. 39-63 : 51-53

Bryopesanser thricyng n. sp.

( Figures 29–31 , Table 1)

Escharina pesanseris: Powell 1967: 274 , text fig. 44. Escharina pesanseris: Gordon 1984: 84 , pl. 29A,B.

Material. Holotype (here selected): NHMUK 1964.8.12.58D, Terra Nova Stn 90, Three Kings Islands, New Zealand, 34°14’ S, 172°05’ E, 25 July 1911, 183 m. Paratype (here selected): NHMUK 1964.8.12.58C, same station as holotype. Other material examined: NHMUK 1964.8.12.58A–B, E, F, Discovery Stn 934, 34°11’ S, 172°10’ E, New Zealand, 17 August 1932, 92– 98 m (figured by Powell).

Description. Autozooids 0.60–0.80 x 0.50–0.60 mm, hexagonal or irregularly polygonal, distinct, separated by grooves. Frontal shield nodular, slightly convex, evenly perforated by numerous small pores, areola septular pores at each lateral and proximal angle. Primary orifice longer than wide, ca 0.12 x 0.09 mm excluding sinus, anter deeply arched, proximal border straight, condyles smooth, drop-shaped sinus as long as wide. Oral spines 9, evenly spaced. Proximal peristome narrowly flared, developing into a spire-like, median mucro during ontogeny. Avicularia originating lateral to most proximal pair of spines, rostra small, open-ended distally, crossbar complete, distally directed, mandibles fan-shaped. Ovicell hyperstomial, producing a thickened proximal edge, with a raised spire-like process frontally. Ovicellate zooids with 8 oral spines, the distalmost pair incorporated into ovicell.

Etymology. Anglo-Saxon threo, three; cyng, king, alluding to the type locality.

Remarks. Bryopesanser thricyng n. sp. is characterised by its longer-than-wide primary orifice, with its straight proximal border, smooth condyles, and the spire-like proximal mucro. The possession of nine spines in autozooids (eight in ovicellate zooids) is unique among the southern-hemisphere species of the genus. The size of the raised spire-like frontal process on the ovicells is likewise unique.

Bryopesanser thricyng n. sp. differs from B. pesanseris and all other Bryopesanser species except B. baderae n. sp. and B. tiara n. sp. in the number of oral spines it produces. However, whilst all three species produce nine oral spines they differ in the shape of the primary orifice, the size and positioning of the avicularian rostra, and the extent of the peristome. It is interesting to note these three species occur at greater depths than the others described herein.

Powell (1967) recorded two other nominal species of Escharina from the Discovery samples from northern New Zealand ― E. waiparensis and E. incognita , both having a dimorphic orifice in brooding zooids. Not only can these species not be included in Bryopesanser for this reason, their generic assignment needs to be re-evaluated.

Distribution. Bryopesanser thricyng n. sp. is only found in northern New Zealand waters (including the Kermadec Ridge).

Figures

FIGURES 29 – 31, Bryopesanser thricyng n. sp. Holotype specimen, NHMUK 1964.8.12.58 D, New Zealand. Figures 32 - 34, Bryopesanser ascendosolaris n. sp. Holotype specimen, NHMUK 1998.6. 318.8, Japan. Scale bars: 29, 500 µm; 30, 200 µm; 31, 100 µm; 32, 100 µm; 33, 500 µm; 34, 200 µm.