Indiella, Sautya, Sabyasachi, Tabachnick, Konstantin R. & Ingole, Baban, 2011

Sautya, Sabyasachi, Tabachnick, Konstantin R. & Ingole, Baban, 2011, A new genus and species of deep-sea glass sponge (Porifera, Hexactinellida, Aulocalycidae) from the Indian Ocean, ZooKeys 136, pp. 13-21 : 14-15

Indiella gen. n.

Diagnosis.

Fan (or funnel)-like basiphytous sponge with thin walls and numerous epirhyses. Framework contains several layers of regular dictyonal strands (mainly from the atrial side) and irregular fused hexactinic spicules (which form a typical aulocal ycoid skeleton) located among them and from the dermal side. Dermalia and atrialia are pentactins. Microscleres are discohexasters.

Etymology.

The name of the genus is derived from its place of collection and refers to the Indian Ocean.

Definition.

Aulocalycidae with fan (or funnel)-like body, epirhyses, and several regular layers of dictyonal strands located mainly on the atrial side.

Remarks.

It is likely that the body is rather fan-like than cup or funnel-like since the fragments are flat, thus the funnel-like body shape should be of a very large diameter. The original shape of the body is already known in Aulocalycoidae : Leioplegma Reiswig & Tsurumi, 1996, while wide funnels are unknown. Basiphytous type of fixation to likely hard substratum is suspected since all other representatives of the family have it. The taxonomic affiliation of genus Cyathella (its attribution to the Aulocalycoida , Aulocalycidae with definition of a new subfamily Cyathellinae was made by Janussen and Reiswig 2003), possessing a rhizophytous type of fixation is unique for recent hexactinellids with rigid skeleton.

The walls in the new genus are relatively thick (in comparison with other representatives of the family). Usually the aulocalycoid skeleton is composed of large hexactins located approximately in a single layer, their rays are distributed in a single plane (the distal one and proximal are bent), fusion takes place at points of mutual contact, so the wall thickness includes an only dictyonal layer. The regular dictional strands are observed in Leioplegma only, they are present as a single layer of parallel units longitudinally distributed, and irregular aulocalycoid skeleton is situated among them ( Reiswig and Tsurumi 1996). The walls in Euryplegma appear to be very complicated and their construction has no equivalent interpretation ( Tabachnick and Reiswig 2000). Cyathella has similar framework construction with several layers of dictyonal strands, but it has no channels and likely no loose spicules.

The presence of epirhyses type of channelization is unique for the family. It is known in Euretidae ( Hexactinosida ), for instance, in Chonelasma (Reiswig & Wheeler, 2002). Among the other types of channelization in Aulocalycoidae , only schizorhyses-like ones are known in Euryplegma , meantime as in the case with complicated wall construction, they may be intercavaedia-like constructions between the atrial cavity and numerous small lateral oscula ( Tabachnick and Reiswig 2000).

The loose spicules are typical for the family where few species possess scepters and uncinates. A more simplified spicule set is observed in Heterochone ( Hexactinosida : Euretidae ), which has no loose spicules other then discohexasters ( Reiswig and Wheeler 2002).

The situation with aulocalycoid, paraulocalycoid and skeleton of Cyathella -like construction ( Reiswig 2002; Janussen and Reiswig 2003) is becoming more complicated after finding in the dictional strands of Farrea numerous axial canals (Reiswig 2004), thus the definition of Aulocalycidae into subfamilies seems to be poorly established and the new genus is regarded as a representative of Aulocalycidae .

Type species.

Indiella ridgenensis sp.n.