Parasmittina, Osburn, 1952

Taylor, Paul D. & Tan, Shau-Hwai Aileen, 2015, Cheilostome Bryozoa from Penang and Langkawi, Malaysia, European Journal of Taxonomy 149, pp. 1-34 : 23-24

Parasmittina sp. 2

Fig. 12 G–I

Material

MALAYSIA: MSL BRY012b, Kampung Kuala Temoyong, Langkawi, colony encrusting interior of large gastropod shell.

Description

Colony encrusting, multiserial, unilamellar. Ancestrula and early astogeny not observed. Autozooids subhexagonal, small, about 0.24–0.32 mm long by 0.18–0.24 mm wide; boundary walls salient with a fine fissure; frontal shield convex, coarsely pustulose, marginal areolar pores large, no pseudopores; orifice slightly wider than high, about 0.09 mm long by 0.10 mm wide, lappets well-developed, highest proximolaterally, tapering distally, a sloping shelf-like proximal orificial rim extending between lappets, lyrula variable, condyles stout; usually two oral spine bases, occasionally one or three; ovicell broader than long, observed only partly formed.Avicularia adventitious present on a small minority of autozooids, located proximolaterally or laterally of orifice, directed proximally or less often laterally, variable in size, up to 0.21 mm long by 0.08 mm wide; rostrum acutely triangular with rounded end, shelf variable, occupying up to one-half length; cross-bar complete or with a medial gap; opesia semi-elliptical.

Remarks

Compared with the other three species of Parasmittina , this unidentified species has very sparse avicularia and prominent lappets highest at the proximolateral corners of the orifice and tapering in height distally ( Fig. 12I ). There are some similarities with Parasmittina hastingsae Soule & Soule, 1973 (see Tilbrook et al. 2001: fig. 14c–d), but the latter has larger autozooids with long condyles and the lappets are highest mediolaterally rather than proximolaterally.

Figures

Fig. 12. Parasmittina spp. — A–C. P. raigioidea Liu et al., 2001. Pulau Betong, Penang, MSL BRY020b. A. Part of colony. B. Autozooids and avicularia. C. Orifice with lyrula and proximally directed adventitious avicularium. — D–F. Parasmittina sp. 1. Kuah jetty, Penang, MSL BRY021b. D. Colony (bottom) becoming overgrown by a colony of P. winstonae (top). E. Ovicellate zooids and proximally directed vicarious avicularia. F. Detail showing a proximally directed vicarious avicularium (upper left of centre) with a proximally directed spatulate adventitious avicularium to its lower right and a distally directed acuminate adventitious avicularium to the lower right of that. — G–I. Parasmittina sp. 2. Kampung Kuala Temoyong, Langkawi, MSL BRY012b; encrusting a large gastropod shell. G. Part of colony. H. Group of zooids. I. Autozooids and an adventitious avicularium. Scale bars: A, H = 500 μm; B, E–F = 200 μm; C, I = 100 μm; D, G = 1 mm.