Aspidoscopulia australia, 2011

Dohrmann, Martin, Göcke, Christian, Janussen, Dorte, Reitner, Joachim, Lüter, Carsten & Wörheide, Gert, 2011, Systematics and spicule evolution in dictyonal sponges (Hexactinellida: Sceptrulophora) with description of two new species, Zoological Journal of the Linnean Society 163 (4), pp. 1003-1025 : 1011-1012

ASPIDOSCOPULIA AUSTRALIA DOHRMANN, GÖCKE & JANUSSEN SP. NOV.

Material examined: One specimen, the holotype ( QM G332077 , SMF 11031), collected 10.xii.2009 during the DDU expedition at Osprey Reef, ROV Dive #4, 13°50.74S, 146°32.88E, on a coral reef wall, depth 656 m.

Description: Body branching with an anastomosing system of tubes, attached to a basal plate, holotype about 0.50 m tall ( Fig. 6 , supporting movie M1, available at Open Data LMU http://dx.doi.org/10. 5282/ubm/data.36). The live sponge was covered by numerous orange zoanthids and by several actinians. Walls thin, outer edges of tubes c. 1 mm; diameter of the oscular tubes about 15 to 25 mm, increasing distally, skeletal channels absent. Colour white, both the living sponge and in ethanol preservation.

Skeleton ( Figs 7 , 8 , Table 4): Dictyonal framework of smooth hexactins forming rectangular, occasionally triangular meshes, mesh width 281–787 Mm, beam thickness 34–113 Mm, the thinnest outer framework parts consist of only one layer of hexactins. Distal rays of dermal outer layer are thickened and more or less tuberculate, no microhexactins were found attached to the dictyonal framework. Loose spicules include dermal and atrial pentactins, microspined with proximal ray length of 88–263 Mm and tangential ray lengths 113–300 Mm. Sceptrules are anchorate clavules, 313–433 Mm in length, microspiny, with a flattened head showing only little expansion and with six to 11 (mean eight) large, separated marginal spines, length 25–35 Mm. The shaft shows a conspicuous whorl of large rounded hooks, 10–25 Mm long, just below the head, which contains a swelling of the central canal, representing the axial cross. Other sceptrules are pileate clavules, 263–313 Mm in length, with an umbrella-like head, 22–30 Mm diameter, framed by c. 25 fused marginal spines, and aspidoscopules, 213–225 Mm length, with a flattened, platelike head and six to seven tines, 25–35 Mm in length. Shaft of aspidoscopules with or without long projecting spines below the head. Rare uncinates observed, 100–125 Mm in length. Microscleres are oxyhexasters, 50–82 Mm diameter, with primary rays, 30–40 Mm length, four to six secondary rays, and discohexasters, microspined, 57–77 Mm diameter, with long primary rays, 25–37 Mm length, and four to six secondary rays.

Remarks: Aspidoscopulia australia sp. nov. differs from the type species of the genus, Asp. furcillata , mainly by the presence of anchorate clavules. Additionally, a small cross at the end of the aspidoscopule shaft, occasionally occurring downward-bending aspidoscopule tines, and microhexactins fused by one ray to the dictyonal framework, as described from Asp. furcillata ( Lévi, 1990; Reiswig, 2002b), were not observed in Asp. australia . Furthermore, the hexasters of the latter are more variable in size than those of the type species.

Etymology: The species name refers to the first record of the genus Aspidoscopulia from Australia.

Figures

Figure 6. Aspidoscopulia australia sp. nov., live photograph taken by the remotely operated vehicle ‘Cherokee’ (http://www.marum.de). Only the specimen on the right was collected (see supporting movie M1). Approximate size of specimen: 0.50 m.

Figure 7. Aspidoscopulia australia sp. nov., skeleton. A, head of aspidoscopule (scale bar = 10 Mm). B–C, anchorate clavules (B, scale bar = 50 Mm; C, scale bar = 10 Mm). D, pileate clavule (scale bar = 30 Mm) and clavule head (inset; scale bar = 5 Mm). E, disco- and oxyhexaster (scale bar = 30 Mm). F, discohexaster (scale bar = 10 Mm). G, dictyonal framework (scale bar = 300 Mm). H–I, aspidoscopule with lateral spines (H, scale bar = 30 Mm; I, scale bar = 10 Mm). J, surface pentactin (scale bar = 100 Mm).

Figure 8. Aspidoscopulia australia sp. nov., spicules. A, aspidoscopule. Left, head and neck of specimen with lateral spine; right, detail of specimen without spines. B, pileate clavule. C, anchorate clavule. D, discohexaster. E, oxyhexaster.