Steginoporella lineata Gordon & Voje & Taylor 2017, n. sp.
Creators: name: Gordon, Dennis P.
name: Voje, Kjetil L.
name: Taylor, Paul D.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Bryozoa
Gymnolaemata
Cheilostomata
Steginoporellidae
Steginoporella
Steginoporella lineata

description: Steginoporella lineata n. sp.
(Figs 1F, 22, 24–25, 35–36)
Etymology. Latin, lineatus, pertaining to a line, alluding to the narrow, linear form of the colony.
Material examined. Holotype: NIWA22945, TAN0205 /64, 30.162° S, 178.578° W, NW slope of Macauley Seamount, west-central Kermadec Ridge, 22 April 2002, 328 m. Paratypes: NIWA 122577, same data as for holotype; NIWA 122578, K795, 33.063° S, 179.567° W, southern Kermadec Ridge, 18 July 1974, 270 m.
Description. Colony small, narrow, linear, not cemented to substratum but attached by sparse rootlets issuing laterally from cuticle of interior-walled colony margin; comprising ribbon-like growths 3–5 zooids across, up to 22 mm long and 3 mm wide. Dried colonies initially light brown, darkening with age, especially the operculum.
Zooids dimorphic. All zooids roundly elongate-rectangular with arcuate distal and proximal margins (mean L/ W = 1.79); lateral margins parallel or slightly converging proximad; widest at level of median process or midlength. Cryptocystal area more than half zooid length, extensive shelf sunken, weakly concave, scattered pseudopores mostly occluded. B-zooids as large as or larger than A-zooids.
Opesial outline of A-zooids with lateral margins widening distad, the arcuate orificial shelf broad; angular articular pivots lacking; median process with distolateral ‘wings’ that do not meet lateral margin; proximomedial foramen of small to moderate size, subrounded. Inner face of operculum smooth, lacking sclerites. Opesial outline of B-zooids somewhat triangular, i.e. with lateral margins converging distad, also with broadly arcuate orificial shelf. Median process as well developed as in A-zooids or with smaller wings. Inner face of mandible with inversely V-shaped sclerites; these can also be clearly seen in frontal view as dark lines.
Polypide not seen. Ancestrula smaller and proportionally narrower than other zooids, tapering proximad, cryptocyst descending to substratum. First daughter zooid budded laterally.
Measurements. In micrometres: ZL 1238±86, 1021–1323 (3, 10); ZW 691±29, 643–744 (3, 10); OpL 201±38, 167–289 (3, 10); OpW 382±60, 221–445 (3, 10); AvL 1292±58, 1200–1389 (4, 10); AvW 746±28, 683–778 (4, 10); AvOpL 254±18, 221–278 (4, 10); AnOpW 467±32, 389–506 (4, 10). AnL 1205; AnW 561.
Remarks. Steginoporella lineata n. sp. is notable as the only species from New Zealand with both A- and Bzooids. The dried mandibles of the B-zooids are darker than those of A-zooids, also indicating pigmentation. The species is unusual in that colonies may attach wholly to a hard substratum, typically basalt, or only partly to a substratum, or not at all, having sparse lateral rootlets.
Distribution. Endemic to New Zealand, central and southern Kermadec Ridge; 270– 328 m.
description: Published as part of Gordon, Dennis P., Voje, Kjetil L. & Taylor, Paul D., 2017, Living and fossil Steginoporellidae (Bryozoa: Cheilostomata) from New Zealand, pp. 345-362 in Zootaxa 4350 (2) on pages 356-357, DOI: 10.11646/zootaxa.4350.2.9, http://zenodo.org/record/1053222