Chelonaplysilla violacea ( Von Lendenfeld, 1883 )

Sim-Smith, Carina, Hickman, Cleveland & Kelly, Michelle, 2021, New shallow-water sponges (Porifera) from the Galápagos Islands, Zootaxa 5012 (1), pp. 1-71 : 8-9

Chelonaplysilla violacea ( Von Lendenfeld, 1883)

( Fig. 3 )

Aplysilla violacea Von Lendenfeld, 1883: 237–269 .

Aplysilla violacea Von Lendenfeld 1889: 704–706 , pl. 46, fig. 13–15.— Bergquist 1967: 162; Bergquist et al. 1971: 100, 103– 104.

Chelonalpysilla violacea Bergquist 1996: 21–22 , pl. 3e, 4e, 7c. — Kelly, 2018: 92; Kelly & Colin, 2016; 59; Lizarazo Rodríguez et al. 2020: 109–110, fig. 19; pl. 2, fig. 6.

Material examined. MCCDRS9431, Beagle Rocks, 0.601° S, 90.633° W, 9 m, 20 Jan 2003; MCCDRS9432, Beagle Rocks, 0.601° S, 90.633° W, 11 m, Jan 2003; MCCDRS9433, Beagle Rocks, 0.601° S, 90.633° W, 8 m, 5 Aug 2003.

Type locality. Port Phillip Heads , Australia .

Habitat and distribution. Australia, New Zealand, Fiji, Solomon Islands, American Samoa, Northern Papua New Guinea, Hawai’i, Palau, Guam, Colombian Pacific, Galápagos Islands (Beagle Rocks). Found growing in shallow waters on hard coral and rock substrates.

Description. Thinly encrusting sponge, up to 10 mm thick, occasionally with lobes, covered in low conules ( Fig. 3A, B ). Fibres often protrude through the surface of the sponge at the apex of the conules. Conspicuous oscules are scattered over the surface of the sponge, flush or surrounded by a slightly raised, membranous rim. Close examination of the surface reveals a characteristic reticulation of embedded sand grains and broken spicules, resulting in the appearance of a whitish surface lace. Texture is soft, compressible. Colour in life is dark purple with a whitish surface sheen.

Skeleton. The surface of the sponge contains a layer of sand and foreign broken spicules ( Fig. 3C ). Large pockets of sand grains are also present within the choanosome. Fibres smooth, erect and sparse, arising from a spongin basal plate, often protruding visibly through the surface. The fibres are strongly concentrically laminated with a central diffuse pith, and free of detritus ( Fig. 3D ); fibres are thin, diameter varying from 36–100 µm.

Remarks. Chelonaplysilla violacea is widely distributed throughout the Pacific Ocean from Papua New Guinea in the west to Hawai’i, the Galápagos Islands and the Colombian Pacific in the east. Specimens from the Galápagos Islands conform to the morphological characteristics of this species.

Order Dictyoceratida Minchin

Figures

FIGURE 3. Chelonaplysilla violacea (Von Lendenfeld, 1883). A. MCCDRS9432, in situ; B. MCCDRS9431, deck photo. C. Cross section of MCCDRS9432 showing the surface sand grains reticulation. D. Spongin fibre from MCCDRS9432 showing the distinct concentric laminations and diffuse pith.