Janulum

Kelly, Michelle, Erpenbeck, Dirk, Morrow, Christine & Soest, Rob Van, 2015, First record of a living species of the genus Janulum (Class Demospongiae) in the Southern Hemisphere, Zootaxa 3980 (2), pp. 255-266 : 258

Genus Janulum de Laubenfels

Janulum de Laubenfels, 1936: 79.

Type species. Janulum spinispiculum ( Carter, 1876) (type by original designation).

Diagnosis. Encrusting sponges with a smooth or lobed to columnar, distinctly punctate surface, with a firm to crisp, fragile texture in life. Colour in life ranges from pale yellow to cream to translucent pale blue. Choanosomal architecture consists of a single category of peculiar spined strongyles arranged in a delicate isodictyal reticulation of single spicules. Ectosome a tangential isodictyal reticulation. Spined strongyles are straight or bent abruptly at each end; typically ends bend to the same side of the spicule but may also bend to opposite sides. Strongyles possess sharp concave spines concentrated in the middle of the strongyle, ends are rounded, smooth, slightly expanded. Spines project perpendicular to the shaft and are aligned in what appear to be short linear spiralling arrays. A few spicules, often thin and immature, may be entirely smooth (modified and expanded from Vacelet (1969) and Boury-Esnault et al. (1994)).