Acanthodesia cf. falsitenuis ( Liu, 1992 ) Taylor & Tan, 2015

Taylor, Paul D. & Tan, Shau-Hwai Aileen, 2015, Cheilostome Bryozoa from Penang and Langkawi, Malaysia, European Journal of Taxonomy 149, pp. 1-34 : 6-8

Acanthodesia cf. falsitenuis ( Liu, 1992) comb. nov.

Fig. 3 A–C

cf. Membranipora falsitenuis Liu, 1992: 112 , figs 3–6.

Material

MALAYSIA: MSL BRY003, Kampung Kuala Temoyong, Langkawi, encrusting an oyster found among fishing debris.

Description

Colony encrusting, multiserial, unilamellar, locally multilamellar. Ancestrula and early astogenetic stages not observed. Autozooids subhexagonal or subrectangular, distally well-rounded, elongate, 0.53– 0.73 mm long by 0.30–0.40 mm wide, zooidal boundaries marked by a fissure; mural rim salient, narrow, pustulose, pustules forming a single row; opesia occupying most of frontal surface, rim broadened distally, edged with tiny pustules; gymnocyst lacking; cryptocyst occupying one-third to almost one-half of proximal end of zooid, planar, sparsely pustulose, with a variably developed, anvil-shaped process bearing long spines extending for up to 0.14 mm over opesia ( Fig. 3 B–C); no spine bases, spinules or tubercles. Kenozooids developed at convergences between colony lobes ( Fig. 3A , upper right corner), variable in shape and size, opesia ovoidal.

Remarks

The most striking feature of this species is the anvil-shaped, spinose cryptocystal process projecting over the opesia ( Fig. 3 B–C). Similar processes were depicted in zooids of two species from the South China Sea – Acanthodesia similis ( Liu, 1992) (see Liu et al. 2001: pl. 9, fig. 2) and A. falsitenuis ( Liu, 1992) (see Liu 1992: fig. 3) – and also in Acanthodesia crenulata (Okada, 1923) , described by Tilbrook (2006: pl. 2b) from the Solomon Islands. Autozooids of A. similis are about half the length of those of the species described here from Langkawi, but judging from the scale bar shown by Liu (1992) in his figure of A. falsitenuis , this latter species is about the same size as the Langkawi material. However, the cryprocystal process is less developed in the Chinese material of A. falsitenuis and this also has zooids of a more rectangular shape with more ragged edges to the lateral cryptocyst.

Figures

Fig. 3. Species of Acanthodesia. — A–C. A. cf. falsitenuis (Liu, 1992). Kampung Kuala Temoyong, Langkawi, MSL BRY003.A. Zooids. B. Detail. C. Cryptocystal process. — D–F. A. peramabulata (Louis & Menon, 2009). Pantai Pasir Hitam, Langkawi, MSL BRY004. D. Part of colony with overgrowth. E. Group of zooids. F. Wide zooid immediately before a row bifurcation. — G–L. A. cf. irregulata (Liu, 1992). Note variation between specimens in the width of the lateral mural rim, which is particularly broad in I, and the development of tubercles, present only in the colony shown in K and L. G. Pulau Betong, Penang, MSL BRY005. H–I. Batu Muang, Penang, MSL BRY026. J. Balik Pulau, Penang, MSL BRY006. K–L. Batu Maung, Penang, MSL BRY007. Scale bars: A, D = 1 mm; B, I, L = 200 μm; C = 50 μm; E–H, J–K = 500 μm.