Powellitheca terranovae, Emanuela Di Martino, Paul D. Taylor, Dennis P. Gordon & Lee Hsiang Liow, 2016

Emanuela Di Martino, Paul D. Taylor, Dennis P. Gordon & Lee Hsiang Liow, 2016, On Powellithecidae fam. nov., a new Pliocene to Recent bryozoan family endemic to New Zealand, with the description of Powellitheca gen. nov. (Bryozoa, Cheilostomata), European Journal of Taxonomy 207, pp. 1-17: 5-8

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http://doi.org/ 10.5852/ejt.2016.207

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scientific name

Powellitheca terranovae


Powellitheca terranovae  gen. et sp. nov.

urn:lsid:zoobank.org:act:F 8 CC 3594 -F 2 CB- 4 E 98-945 E- 800 B0C 2 A 460 C

Figs 2View Fig. 2 A –F, 7, Table 1

Emballotheca waipukurensis  – Powell 1967: 336, fig. 87. — Gordon 1989: 36, pl. 17, figs E –F. — Gordon et al. 2009: 291.


Colony encrusting. Zooids rectangular, arranged in well-defined rows. Frontal shield convex, regularly and evenly perforated, apart from a narrow peristomial area lacking pores, granular. Small, frontal, multiporous septula at the distolateral and proximolateral corners of the zooids. Lateral zooidal communications through multiporous septula visible on the vertical walls. Orifice with a convex proximal lip and two small, lateroproximally placed condyles, bearing an anvil-shaped median lyrula directed downwards and not visible in frontal view. Oral spines absent. Ooecium large, globular, occupying most of the frontal shield of the next distal zooid, porous and granular with the same texture as the frontal shield. Avicularia uncommon, single or paired, with short condyles and tapered rounded rostrum distolaterally directed.


Named after the ‘Terra Nova’ Expedition, the source of several specimens of this species described initially by Powell (1967).

Material examined


NEW ZEALAND: NIWA 98983, Recent, 2 Dec. 1981, Stephens Hole, Cook Strait, NZOI Station Q686, 40˚ 41.3 ' S, 174 ˚03.8' E, 205 m.


Colony encrusting, multiserial, unilaminar; colour yellow. Ancestrula not observed. Zooids arranged in well-defined rows ( Fig. 2View Fig. 2 A), distinct, boundaries marked by very narrow furrows, quadrate to rectangular generally with squared corners, straight or curved zooidal lateral boundaries, longer than broad (mean L/W = 2.02). Polypides with 19 tentacles. Frontal shield lepralioid, convex, granular, regularly and evenly perforated by 50–80 small, circular or slit-like pseudopores about 15–20 μm in diameter ( Fig. 2View Fig. 2 B). Small, rounded triangular, multiporous frontal septula, bearing three or four inconspicuous pores, about 5–6 μm in diameter, placed at distolateral and proximolateral zooidal corners ( Fig. 2View Fig. 2 B), often hidden in ovicellate zooids owing to a different surface topography in that area. Orifice placed distally, generally broader than long, with the proximal rim gently convex and two tiny condyles placed proximal to the mid-lateral position; an imperforate, granular, slightly raised peristomial rim surrounding the orifice ( Fig. 2View Fig. 2 E). An anvil-shaped lyrula, placed medially, 60–90 μm broad, occupies about half of orifice width, directed downwards, vertically or distovertically, and not visible in frontal view ( Fig. 2View Fig. 2 E). Oral spines and suboral umbo absent. Ovicells hyperstomial. Ooecia globular, large, occupying almost the entire frontal shield length of the next distal zooid forming the ooecium. Ectooecium uncalcified. Endooecium thick, granular like the frontal shield but with a finer granulation, with deep oval and round pits (11–20 μm in diameter) and with a proximal, granular, imperforate band and a narrow, smooth, frontal rim, slightly upturned ( Fig. 2View Fig. 2 A, C, F). Primary orifice of fertile zooids larger than that of autozooids, rounded quadrangular, slightly broader than long with a smooth, stout suboral umbo ( Fig. 2View Fig. 2 A, C, F); secondary orifice slit-like ( Fig. 2View Fig. 2 A). Avicularia uncommon, adventitious, usually single, rarely paired, lateral to the orifice, on or adjacent to ovicellate zooids, distolaterally directed, with short condyles, no calcified crossbar, rounded tapered rostrum ( Fig. 2View Fig. 2 D). Oval, multiporous (at least 14 pores) septula in lateral vertical walls, about 95–120 μm long by 45–55 μm wide ( Fig. 2View Fig. 2 C). Intramural, reparative budding observed ( Fig. 2View Fig. 2 A).


Originally included in the ‘ Emballotheca waipukurensis  group’ together with the Plio –Pleistocene P. waipukurensis  comb. nov. (see description below), the Recent specimens now assigned to P. terranovae  gen. et sp. nov. differ from true P. waipukurensis  comb. nov. in having an anvil-shaped median lyrula that is difficult to observe in frontal view because it is directed either vertically downwards or only slightly distally angled. Further differences are the lack of a suboral umbo in the non-ovicellate zooids of P. terranovae  gen. et sp. nov., a feature that in this species is restricted to the female zooids, and the different shape of the avicularium rostrum, which is spatulate in P. waipukurensis  comb. nov. but distally tapered and rounded in P. terranovae  gen. et sp. nov. They also differ in the size of the zooids, orifice and ooecia, which are slightly larger in P. terranovae  gen. et sp. nov.


This species is known from the Cook Strait area and the Three King Islands, from 75 to 205 m depth.

Table 1. Measurements in microns of Powellitheca terranovae gen. et sp. nov.

  N (zooids, colonies) Mean   Min Max
      ± 12    
      ± 18    
      ± 24    
      ± 25    
      ± 10    
      ± 12    

University of Newcastle


National Institute of Water and Atmospheric Research


New Zealand Oceanographic Institute














Powellitheca terranovae

Emanuela Di Martino, Paul D. Taylor, Dennis P. Gordon & Lee Hsiang Liow 2016

Emballotheca waipukurensis

Gordon D. P. & Taylor P. D. & Bigey F. P. 2009: 291
Gordon D. P. 1989: 36
Powell N. A. 1967: 336