Plagioecia parva, Gordon & Taylor, 2010

Gordon, Dennis P. & Taylor, Paul D., 2010, New seamount- and ridge-associated cyclostome Bryozoa from New Zealand, Zootaxa 2533 (1), pp. 43-68 : 54-55

Plagioecia parva n. sp.

( Fig. 7 A–D )

Material examined. Holotype: NIWA 61248 , from cruise TAN0413, Stn 129, 37°20.40– 37°20.25’S, 177°06.69– 177°06.81’ E, Bay of Plenty, on Mahina Knoll northwest of White Island , 275–335 m depth, collected 14 November 2004 . Paratypes: NIWA 61249 , same locality as holotype .

Distribution. Continental slope, central Bay of Plenty, New Zealand, 275 m.

Etymology. From Latin parvus, small.

Description. Colony encrusting, more or less circular, central disc of zooids 1.90–2.24 mm diameter, with a broad, thin peripheral lamina that may increase overall colony diameter up to 3.08 mm. One or two small subcolonies able to develop at the colony margin in the zooidal budding zone. Autozooidal peristomes longest behind the peripheral budding zone, up to 0.37 mm high; apertures circular to oval, 0.06–0.10 mm in diameter, those in broad central zone comprising only short rims, the zooidal tubes all sealed with finely porous calcareous diaphragms. Zooids with peristomes separated or several peristomes more or less connate in short radial rows; centralmost zooids somewhat spirally disposed; surface calcification of colony between peristomes with fine, wavy, growth lines. Peristomial interiors lacking mural spines.

Gonozooid at colony periphery, brood chamber transversely elongate and broadly crescentic, tapering somewhat on each side laterally, 1.28 mm wide, up to 0.45 mm long; ooeciostome mid-distal, forming a short tube bent towards the colony centre, the ooeciopore transversely oval, 0.014 mm in transverse width.

Remarks. This species is so far known only from the type locality, which yielded three fertile colonies. Compared to the type species of Plagioecia , this new species has smaller zooids with more distantly spaced apertures.

Figures

FIGURE 7. Plagioecia parva n. sp. (TAN0413 Stn 129). A, holotype colony with brood chamber; B, brood chamber in A; C, ooeciostome, and crystallites of marginal lamina; D, another colony with a developing subcolony.