Plumatella crispa, Wood, 2022

Wood, Timothy S., 2022, Phylactolaemate bryozoans at the Zoological Survey of India and a taxonomic key to Indian Phylactolaemata, Zootaxa 5200 (2), pp. 401-435 : 418-419

Plumatella crispa n. sp.

( Fig. 15 )

Holotype. ZSI P163 collected 1 January 1922 in “ Canton , China ” by A.W.L. Oliver, originally labeled “ Plumatella fruticosa ”.

Diagnosis. The colony appears as a tangle of free branches; dorsal margin of the floatoblast slightly curled inwards.

Etymology. The specific epithet is from the Latin adjective crispus, meaning curled or curly, in reference to the upturned dorsal margin of the floatoblast.

Description. Colony appearing as a tangle of branching tubules extending from the substratum; floatoblasts long and narrow ( Table 1 ), floatoblast dorsal fenestra relatively small, with length and width less than half of corresponding outer dimensions of the floatoblast; tubercles on the dorsal fenestra low and rounded, with little space between them, dorsal valve margins distinctively scalloped or lightly curled; floatoblast ventral fenestra broadly oval, nearly twice as wide as the dorsal fenestra, with low, rounded tubercles that fade towards the center.

Distribution. The species is known only from its type locality in China.

Remarks. The holotype colony is attached in places to a small piece of reed. Sessoblasts are absent. The marginal curling of the floatoblast is best seen with scanning microscopy, but is nevertheless detectable when the isolated valve is viewed with a compound microscope. The initial designation of this species as Plumatella fruticosa is understandable, since colonies of both species have free branches, the floatoblasts are long and narrow, and the dorsal fenestrae are relatively small. An important difference is one of scale: with P. fruticosa the floatoblast length is over 500 µm ( Fig. 20b ), while in P. crispa n. sp. it is less than 400 µm.

Figures

FIGURE 15. Floatoblasts of Plumatella crispa n. sp. from the holotype, P163 (a) Partial SEM view of dorsal valve; (b) Enlarged portion of floatoblast dorsal valve margin showing distinctive crease; (c) SEM view of ventral valve; (d) Floatoblast valves seen with light microscopy. Scale bars = 50 µm for a, c, and d, 10 µm for b.

FIGURE 20. Miscellaneous floatoblasts. (a) Hyalinella lendenfeldi; (b) Plumatella fruticosa not from India; (c) Plumatella casmiana; (d) Plumatella javanica; (e) Rumarcanella vorstmani; (f) Swarupella andamanensis; (g) Swarupella divina; (h) Varunella coronifera; (i) Varunella indorana. Scale bar = 100 µm. Figure (i) modified from Wiebach, 1974.