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Taxon
Acryptolaria operculata Stepanjants, 1979
Nomenclature
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Family: LafoeidaeGenus: Acryptolaria
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Synonyms: 1
SUMMARY
Stolons reptant on substrate, tubular, narrow, coalescing into erect, almost straight stems; sometimes single hydrothecae arising from stolons between stems.
Taller stems to 2 mm thick at base, basal 5–10 mm unbranched; lower stem region strongly fascicled, polysiphonic tubes mostly linear, running up stem and along primary branches. Complex colonies with up to four orders of branching; branches more or less alternate, usually in one plane, primary and subsequent branches often originating just above a hydrotheca, ultimate branches (hydrocladia) and some branches in lower stem region monosiphonic.
Hydrothecae biseriate, tubular, subalternate, usually frontal on branch, long, gracefully arched outwards, abcauline wall concave, often a minor swelling in proximal wall; adcauline wall smoothly convex, one third adnate to hydrocladium, adnate part narrowing a little proximally and fading into hydrocladium; hydrocladium fairly narrow behind adnate hydrothecal wall. Margin circular, transverse to hydrothecal axis, rim slightly everted, almost parallel to hydrocladial axis; margin may have up to 14 close replications bending plane of rim away from axis of hydrotheca. Cauline hydrothecae partially immersed in polysiphonic tubes of stem and primary branches; tubes then often contorted around hydrothecae.
Hydranths contracted and wrinkled; with c. 20 tentacles and clavate hypostome; hydranth attached to base of adnate hydrothecal wall by a ring of tissue.
Perisarc of stem and branches thick and smooth, perisarc of hydrothecae thinner and shining.
Colour: Stems pale honey-yellow fading to almost colourless at tips of branches (Preserved material). Hydranths may have been deep golden brown.