Euplectella, Owen, 1841

Tabachnick, Konstantin, Fromont, Jane, Ehrlich, Hermann & Menshenina, Larisa, 2019, Hexactinellida from the Perth Canyon, Eastern Indian Ocean, with descriptions of five new species, Zootaxa 4664 (1), pp. 47-82 : 64

Euplectella sp.

Material examined. Australia: Western Australia: WAM Z35338 , WAM Z88495, 2 fragments, Perth Canyon (31 o 58’17’’S, 115 o 06’00’’E to 31 o 57’19”S, 115 o 06’50”E, Figure 1 ), 848–1050 m, J. Fromont and C. Whisson, sled, 29/11/2005, RV Southern Surveyor station SS1005/071 ,.

Body. Specimens are fragments of sponge bodies.

Spicules. Megascleres. Principalia are large stauractins. Common choanosomal spicules are pentactins and hexactins. Some fragments of long spiny spicules are probably basalia. Dermalia are hexactins with rays roughened in distal parts and smooth at the base, conically pointed. The distal ray of the dermal hexactin is 0.089 –0.340 mm long (n=20, avg: 0.180 mm, std: 0.071 mm), tangential rays are 0.100 – 0.266 mm long (n=20, avg: 0.206 mm, std: 0.038 mm), the proximal ray is 0.340 –0.666 mm long (n=14, avg: 0.498 mm, std: 0.117 mm), the diameter is 0.011 – 0.019 mm. Atrialia are pentactins with spiny rays which could not be separated from the choanosomal pentactins.

Microscleres. Microscleres are floricomes, oxyhexasters and rare graphiocomes. The floricomes are 0.133 – 0.170 mm in diameter (n=25, avg: 0.154 mm, std: 0.009 mm), the primary rosette is 0.015 –0.031 mm in diameter (n=25, avg: 0.019 mm, std: 0.004 mm). The oxyhexasters with 2–6 secondary rays are 0.074 –0.133 mm in diameter (n=25, avg: 0.090 mm, std: 0.013 mm), the primary rosette is 0.010 –0.019 mm in diameter (n=25, avg: 0.013 mm, std: 0.002 mm). Graphiocomes have primary rosettes 0.018 –0.023 mm in diameter (n=9, avg: 0.020 mm, std: 0.002 mm) with the secondary rays (rhaphides) largely rare broken fragments.

Remarks. The specimens are fragments potentially of young sponges so it is not possible to identify them to species.

Distribution. The genus is cosmopolitan and has been reported off southern Australia and Indonesia by Ijima (1927), Reiswig (1992), Tabachnick et al. (2008), and New Zealand by Reiswig & Kelly (2018).

Figures

FIGURE 1. Map of Perth Canyon. Triangles are RV Falkor stations and circles are RV Southern Surveyor stations.