Leucascandra Borojevic & Klautau, 2000

Borojevic, Radovan, Boury-Esnault, Nicole & Vacelet, Jean, 2000, A revision of the supraspecific classification of the subclass Calcaronea (Porifera, class Calcarea), Zoosystema 22 (2), pp. 203-263 : 231-232

Genus Leucascandra Borojevic & Klautau, 2000

TYPE SPECIES. — Leucascandra caveolata Borojevic & Klautau, 2000 by monotypy.

DIAGNOSIS. — Jenkinidae with a complex cormus composed of copiously branched and anastomosed tubes. Each tube has a thin wall with a rather irregular alveolar type of leuconoid aquiferous system, and an inarticulate choanoskeleton that is supported only by unpaired actines of subatrial triactines. Both cortical and atrial skeletons consists of a thin layer of tangential triactines and/or tetractines.

DESCRIPTION

In the Clathrinida , tubular sponges frequently form a large cormus composed of ramified and anastomosed tubes (e.g. Clathrina, Ascandra, Ascaltis , Leucascus , Leucaltis ). In the Leucosoleniida , this growth form is quite rare. While the Jenkinidae from cold Antarctic or Arctic waters grow as small solitary tubes, those from warmer waters can form large complex cormi. The genus Leucascandra is thus characterized by a tendency to form a large cormus composed of extensively branched and anastomosed tubes ( Fig. 26), an inarticulate choanoskeleton, and a thin cortex ( Fig. 27 ).

cx

Figures

FIG. 27. — Leucascandra organization. Transverse section through the sponge wall; the choanoskeleton is composed of only subatrial triactines and the atrial skeleton contains triactines and tetractines. Abbreviations: a, atrial skeleton; ch, choanoskeleton. Scale bar: 40 µm.