Order LYCHNISCOSIDA Schrammen, 1903

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Diagnosis

Recent forms all basiphytous; body form calyciform, cylindrical to globular, with tubular axial atrial cavity and radial branching and anastomosing tubules or labyrinthic spaces subdivided and supported by pillars and plates; walls are unchannelized but fine tubules of one group may be interpreted as schizorhyses; dictyonalia are arranged in ranks parallel with growth margin or are unorganized; outer surfaces of mature specimens may be enveloped by a dense mat of loose spicules which may be hypersilicified and fused to form a dense outer siliceous crust; dermalia and atrialia are rough pentactins, but hexactin atrialia may line axial cavity (atrium); accessory hexactins occur as parenchymalia; microscleres always include regular spherical discohexasters, graphiocomes or onychexasters may also be present but never together; uncinates and sceptrules are absent.

ID Keys

KEY TO FAMILIES
(1) With walls/pillars several dictyonalia in thickness; lychniscs in ranks ----------------------------- Aulocystidae
With tubule walls 1–3 dictyonalia in thickness; lychniscs not in ranks --------------------------------- Diapleuridae

Diagnosis References

Reiswig, H. 2002. Order Lychniscosida Schrammen, 1903. 1377 in Hooper, J.N.A. & Soest, R.W.M. Van (eds). Systema Porifera. A guide to the classification of sponges. New York : Kluwer Academic/Plenum Publishers Vol. 2. [1377]

History of changes