Aspidoscopulia ospreya, 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 : 1012-1014

ASPIDOSCOPULIA OSPREYA DOHRMANN, GÖCKE & JANUSSEN SP. NOV.

Material examined: One specimen, the holotype ( QM G332104 , SMF 11032), collected 14.xii.2009 during the DDU expedition at Osprey Reef, ROV Dive #8, 13°49′S, 146°32′W, depth 747 m.

Description: Body branching with an anastomosing system of tubes attached to a basal plate, holotype about 0.70 m tall, walls thin, outer edges of tubes c. 1 mm; diameter of the oscular tubes about 20 to 30 mm, increasing distally, skeletal channels absent ( Fig. 9 , supporting movie M2, available at Open Data LMU http://dx.doi.org/10.5282/ubm/data.36). Colour white, both the living sponge and in ethanol preservation.

Skeleton ( Figs 10–11 , Table 5): Dictyonal framework of smooth hexactins forming rectangular, occasionally triangular meshes, mesh width 217–652 Mm, beam thickness 54–109 Mm (mean values), the thinnest outer framework parts probably (not observed) consist of only one layer of hexactins. Distal rays of dermal outer layer are thickened and more or less tuberculate, no microhexactins were observed attached to the dictyonal skeleton. Dermalia and atrialia are microspined pentactins with proximal ray length 230–340 Mm, paratangential ray lengths 250– 340 Mm. Only sceptrules observed are microspined anchorate clavules similar to those in Asp. australia , length 275–338 Mm, with four to eight (mean six) large, separated marginal spines, length 15–27 Mm. The shaft shows a whorl of large rounded hooks, 7–20 Mm long, just below the head. Head contains the axial cross represented by a swelling of the axial canal. Rare uncinates observed, 250–950 Mm in length. Microscleres are oxyhexasters, 95–145 Mm in diameter, with primary rays 43–70 Mm length, two to three secondary rays, and discohexasters, microspined, 66–105 Mm in diameter with primary rays, 30–50 Mm length, three to four secondary rays.

Remarks: Aspidoscopulia ospreya differs from the type species, Asp. furcillata , by the presence of anchorate clavules and the absence of aspidoscopules. Furthermore, microhexactins fused by one ray to the dictyonal framework, if present at all, are not as abundant as in the type species. A close relationship of Asp. ospreya to Asp. australia is clearly indicated by the very similar appearance of the anchorate clavules in these two species. However, Asp. ospreya differs from Asp. australia by the absence of other sceptrules – pileate clavules or aspidoscopules were not observed in this species, whereas they are common in Asp. australia . The anchorate clavules are generally smaller and show a lower number of marginal spines in Asp. ospreya (mean six) compared to Asp. australia (mean eight); also, both oxy- and discohexasters are generally larger, but with fewer secondary rays, in Asp. ospreya than in Asp. australia .

Assignment of QM G332104 and QM G332077 to two distinct species is further justified by significant differences at the molecular level, with uncorrected p-distances of 0.0009, 0.0034, 0.0498, and 0.0687 for 18S, 28S, 16S, and COI sequences, respectively.

Etymology: Species name refers to the type locality, Osprey Reef.

Figures

Figure 9. Aspidoscopulia ospreya sp. nov., live photograph taken by the remotely operated vehicle ‘Cherokee’ (http://www.marum.de). Approximate size of specimen: 0.70 m.

Figure 10. Aspidoscopulia ospreya sp. nov., skeleton. A-B, anchorate clavules (scale bars = 25 Mm). C, discohexasters (scale bar = 30 Mm). D, surface pentactin (scale bar = 100 Mm). E, oxyhexaster (scale bar = 30 Mm). F, dictyonal framework (scale bar = 300 Mm).

Figure 11. Aspidoscopulia ospreya sp. nov., spicules. A, anchorate clavule. B, surface pentactin. C, discohexaster.