Calloporina spinosa, Branch & Hayward, 2005

Branch, M. L. & Hayward, P. J., 2005, New species of cheilostomatous Bryozoa from subantarctic Marion and Prince Edward Islands, Journal of Natural History 39 (29), pp. 2671-2704 : 2695-2697

Calloporina spinosa sp. nov.

( Figure 10 D–G)

Material

Holotype: St. 53 Marion Island (46 ° 55 9 S, 37 ° 33 9 E), 606–775 m, SAM A27564. Description

Colony encrusting on rock, forming small, unilaminar patches. Autozooids oval to hexagonal, convex, separated by thin ridges marking the vertical walls; 0.55–0.6X 0.4– 0.45 mm. Frontal shield irregularly spinous, the ‘‘spines’’ representing projections of the frontal calcification; imperforate centrally, but with large, rounded areolar pores closely spaced around the margin. Primary orifice slightly wider than long, 0.1X 0.09 mm, with straight proximal border. Six short, cylindrical oral spines present. Ascopore close to the proximal border of the orifice, separated from it by a distance equivalent to one-quarter orifice length; narrowly crescentic, with a toothed rim, set within a shallow dish, ca 0.05 mm diameter; a thick, raised peristome, with coarsely crenulated edge, extends proximally between the bases of the proximal spine pair, enclosing the ascopore. One or two large pores present within the peristome, close to the proximo-lateral corners of the orifice, and equally large pores are present around the distal end of the autozooid. Ovicell not found.

Etymology

Latin, spinosus, thorny, with reference to the spinous frontal shield calcification of the zooids.

Remarks

The rather robust frontal calcification, with deep areolar pores, and the flaring peristome enclosing the ascopore, suggest that this new species is more appropriately accommodated within Calloporina than Fenestrulina , although the distinction between the two genera is perhaps becoming less clear. Calloporina is characterized by a thickly calcified ovicell, with only a narrow area of entooecium exposed frontally. Most species bear adventitious avicularia, and have large marginal areolar pores. However, in Calloporina patagonica Hayward and Ryland, 1990 avicularia are only sparsely present and the ovicell has a broad frontal area of exposed entooecium, and rather resembles that of Fenestrulina pumicosa sp. nov. (below). The thick peristomial calcification seen in C. spinosa sp. nov. is also a feature of C. patagonica . Further material of this new species is required before its taxonomic affinity can be confidently established. It is apparent, however, that the systematics of Fenestrulina , Calloporina , and related genera in the southern hemisphere are in need of review. Calloporina was introduced for a Miocene fossil, C. decorata (Reuss, 1848) , that is said to be extant, though rare, in the Mediterranean ( Zabala and Maluquer 1988). With the exception of C. patagonica , the genus is otherwise known from the western Pacific, from Japan to Australasia, and from Tertiary deposits of Australia and New Zealand.

Figures

Figure 10. (A–C) Phonicosia jousseaumei, SAM A27573: (A) autozooids and incomplete ovicell, X70; (B) ovicelled autozooid, X60; (C) detail of orifice and pores, X200. (D–G) Calloporina spinosa sp. nov., SAM A27564: (D) autozooid, X100; (E) autozooid, X100; (F) orifice, X160; (G) ascopore, X800.