A revision of the supraspecific classification of the subclass Calcaronea (Porifera, class Calcarea) Author Borojevic, Radovan Departamento de Histologia e Embriologia, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Caixa Postal 68021, 21941 - 970 Rio de Janeiro (Brazil) radovan @ iq. ufrj. br radovan@iq.ufrj.br Author Boury-Esnault, Nicole Author Vacelet, Jean Centre d’Océanologie de Marseille (CNRS-Université de la Méditerranée, UMR 6540 DIMAR), Station marine d’Endoume, F- 13007 Marseille (France) esnault @ com. univ-mrs. fr jvacelet @ com. univ-mrs. fr text Zoosystema 2000 22 2 203 263 journal article 10.5281/zenodo.5392175 1638-9387 5392175 Genus Aphroceras Gray, 1858 TYPE SPECIES . — Aphroceras alcicornis Gray, 1858 by monotypy. DIAGNOSIS. — Grantiidae with a leuconoid organization. The cortex is supported, at least in part, by giant longitudinal diactines. DESCRIPTION Aphroceras is differentiated from Leucandra by the presence of internal longitudinal diactines in the cortex (Fig. 22). In a previous study (Borojevic 1966), it was shown that the number of these spicules can be quite variable, ranging from a continuous dense layer to only very rare spicules, or even absence. In the latter case, it is not possible to distinguish this sponge from a typical Leucandra . However, we retain this genus at present, as we feel that the typical Aphroceras are easy to identify. Dendy & Row (1913) pointed out that Aphroceras probably derives directly from Leucandra by a secondary acquisition of longitudinal internal diactines, and not from Ute by a modification of the syconoid DESCRIPTION

Borojevic R., Boury-Esnault N. & Vacelet J.
cx
ch
ss as
a
FIG. 22. — Diagram of a transverse section through the wall of Aphroceras ensata (Bowerbank, 1858) . Abbreviations: a , atrium; as , atrial skeleton; ss , subatrial spicules; ch , choanosome; cx , cortex (from Borojevic 1966). Scale bar: 100 µm.
aquiferous system into the leuconoid one. Our studies on A. ensata (Bowerbank, 1858) (Borojevic 1966) , however, point to a close relationship between Ute and Aphroceras . Genus Leucandrilla n. gen. TYPESPECIES.— Leucilla wasinensis Jenkin, 1908BMNH 226	1908.9.25.59 byoriginaldesignation.Not Leuconiawasinensis BMNH 1936.3.4.537, in Burton (1959). DIAGNOSIS. — Grantiidae with a leuconoid organization. In addition to triactines the cortex contains tetractines, with the apical actines turned into the choanoderm. The articulate choanoskeleton is supported by subatrial triactine spicules, and numerous rows of choanosomal triactines and/or tetractines, with apical actines of cortical tetractines in the distal region. ZOOSYSTEMA • 2000 • 22 (2)

Leucandrilla is differentiated from Leucandra by the presence of tetractines in the cortical skeleton ( Fig. 23 ). Like Aphroceras , which is distinguished from Leucandra by the presence of cortical diactines, the separation between Leucandrilla and Leucandra is not clear-cut. Dendy (1913), Dendy & Row (1913) and Borojevic & Boury-Esnault (1987) have already pointed out that some of the sponges with cortical tetractines that had been classified among Amphoriscidae are not very different from a typical Leucandra , but are quite distinct from Leucilla , and should consequently be classified in the Grantiidae . In particular they have a complete articulate choanoskeleton, reminiscent of the grantiid organization, which is absent in Amphoriscidae . While Dendy (1913) proposed that these sponges should be included in Leucandra , we now propose to isolate them in a separate genus in the family Grantiidae , analogous with the recognized separation of Aphroceras . It should be noted that we consider the cortical tetractines in this genus to be a secondary character, corresponding to a modification of normal cortical triactines, while cortical tetractines of the family Amphoriscidae are a primary character, marking an independent evolutionary line. In addition to L. wasinensis (Jenkin, 1908b) , which we propose to be the type species of the genus Leucandrilla , other sponges that had been classified in the genus Leucandra , such as L. intermedia (Row, 1909) and L. lanceolata (Row & Hôzawa, 1931) , also belong to this genus.