Sertularella quadrispinosa (Watson, 2003)

Fig. 15H

Calamphora quadrispinosa Watson, 2003: 168, fig. 18.

Description: Colonies comprising both stolonal hydrothecae and short, unbranched or sparinglybranched, erect stems arising from creeping, branching, tubular hydrorhiza. Stolonal hydrothecae pedicellate, barrel-shaped, slightly asymmetrical in lateral view, narrowing a little below aperture, walls smooth to weakly undulated, especially on lower third; base pierced by central, circular hydropore with short, upturned collar; hydrothecal margin quadrate, distinctly everted, provided with 4 broad, sharply-pointed cusps separated by low, semicircular embayments; a 4-flapped operculum; hydranths with ca. 16 filiform tentacles. Gonothecae stolonal, arising in the vicinity of a hydrotheca; pedicellate, barrel-shaped, walls provided with 6-9 transverse flanges, deepest in distal third, shallower proximally; aperture apical, surrounded by 4 prominent, equidistant, more or less inwardly-curved spines.

Dimensions: Length of the hydrothecal pedicel 64-224 μm. Total length of hydrotheca 1100-1280 μm, maximum width 506-561 μm, diameter at aperture 440- 480 μm. Length of the gonothecal pedicel 120-176 μm. Maximum width of gonotheca 520-640 μm.

Remarks: The present species is included in the genus Sertularella because its colonies, besides the commonest stolonal hydrothecae, comprise short, unbranched or sparingly-branched, erect stems. Indeed, Choong et al. (2012) stated that “colony form may be an insufficient criterion for assigning species of pedicellate Sertularella with individual hydrothecae rising from their hydrorhizae to a separate genus Calamphora ”. The gonotheca of S. quadrispinosa is illustrated by Watson (2003).

Distribution: Only known from Macquarie I., Australia (Watson, 2003).