Cyclacanthia bellae ( Samaai & Kelly, 2003 )

Samaai, Toufiek, Kelly, Michelle, Ngwakum, Benedicta, Payne, Robyn, Teske, Peter R., Janson, Liesl, Kerwath, Sven, Parker, Denham & Gibbons, Mark J., 2020, New Latrunculiidae (Demospongiae, Poecilosclerida) from the Agulhas ecoregion of temperate southern Africa, Zootaxa 4896 (3), pp. 409-442 : 433-434

Cyclacanthia bellae ( Samaai & Kelly, 2003)

( Fig. 15A , Tables 6, 7)

Latrunculia bellae Samaai & Kelly, 2003: 14–15 , fig. 3C, 4D, 5D.

Cyclacanthia bellae, Samaai, Govender and Kelly (2004) : 5 –6, figs. 2F, 3A, E–F, 4A, Table 1.

Type & locality (not examined). Holotype—NHMUK 2003.1.10.1, Algoa Bay , Ryi Banks, 8 nm east of Port Elizabeth, South Africa, 33.992° S, 25.876° E, 22 m, collected by Patrick L. Colin, CRRF, 12 Oct 1998 .

Diagnosis. Thinly encrusting sponge ( Fig. 15A ), 5 mm thick in life, surface crowded with very small conical oscules and numerous thin-lipped crater-like areolate porefields. Compressible in life, slightly felty to the touch, emerald green in life, dark chocolate brown internally and in preservative. The sponges were collected from a moderately rugged rocky bottom with patches of sand between rocks, on Ryi Banks, Algoa Bay, south-eastern South Africa, at 10– 22 m. Spicules. Megascleres are styles. Smooth, hastate, centrally thickened straight or slightly sinuous styles, 364 (319–400) long by μm wide. Microscleres ( Figs. 14 , 15 ) are acanthose isospinodiscorhabds. The median whorl is composed of four groups of discrete spines distributed evenly around the shaft, the spines of the manubrium and apical whorl are slanted obliquely from the median whorl and the spines are orientated at different angles within each whorl. A single spike protrudes from the apex and base of the spicule, all spines are markedly acanthose, 46 (44–51) μm long. Skeleton ( Fig. 15C ) is made up of large dense swathes of megascleres, 230–250 μm wide, emerge from the base of the sponge towards the upper choanosome, where they diverge to form loose brushes and a wispy polygonal reticulation of tracts c. 60–180 μm wide, forming a mesh c. 230 μm wide. Interstitial megascleres and microscleres are abundant. The ectosome of tangentially arranged styles is c. 320 μm thick and is aligned by an irregular palisade of densely packed isospinodiscorhabds. The species occurs on moderate rugged rocky bottoms with patches of sand between rocks between a depth of 10– 22 m. The sponge contains novel biologically active pyrroloquilonine alkaloids, discorhabdin M and G, Makaluvic acid A and discorhabdin derivatives that may have pharmacological potential [Cytotoxicity against Human Colon Tumour cell line (HCT 116)] ( Antunes et al., 2005) (modified from Samaai et al. 2004).

Distribution. Algoa Bay, Eastern Cape coast, Agulhas ecoregion, South Africa

Remarks. Cyclacanthia are similar in their general morphology to other Latrunculiidae , with fistular oscula and areolate porefields distributed over the sponge surface. However, within Latrunculiidae , Cyclacanthia species are notably thinly encrusting with a soft, compressible texture and have acanthose isospinodiscorhabds as microscleres ( Fig. 14 ) ( Samaai et al. 2004). Spines develop simultaneously on the end of a straight thin protoisochiarhabd shaft followed by median spines (see fig. 2D in Samaai et al. 2004). The spines develop directly from the shaft and do not transform into circular plates with serrated margins as in Latrunculia or into truncate tubercles with rounded acanthose ends as in Tsitsikamma ( Samaai and Kelly 2002; Samaai et al. 2004; Parker-Nance et al. 2019). Additional diagnostic characters include the presence of broad swathes of megascleres that diverge from the base of the sponge towards the upper choanosome, where they form loose brushes and the typical wispy reticulation of most Latrunculiidae . Cyclacanthia is endemic to South Africa and is a predominantly shallow water genus occurring in warm temperate to subtropical waters, and is usually associated with rocky reef substrata, especially in areas that has cold upwelling cells and extreme current flow. The genus as presently recognised is cohesive ( Samaai et al. 2004) and contains three well-defined species. The discovery of the new species from the offshore Amathole region extends the distribution of this genus further south in the Agulhas ecoregion.

Figures

FIGURE 14. Isospinodiscorhabd microsclere morphology in Cyclacanthia Samaai & Kelly, 2004: A. Type species, C. bellae (Samaai and Kelly, 2003), specimen NHMUK2003.1.10.1; B. C. mzimayiensis Samaai & Kelly, 2004, holotype SAM H-5082; C. C. cloverlyae Samaai & Kelly, 2004, holotype SAM H-5080; D. C. rethahofmeyri sp. nov., holotype SAMC-A090895, small isoconicorhabds; E. C. rethahofmeyri sp. nov., holotype SAMC-A090895, large isoconicorhabds.

FIGURE 15. Cyclacanthia bellae (Samaai & Kelly, 2003), holotype NHMUK2003.1.10.1:A. In situ specimen; B. Isospinodiscorhabd; C. Skeletal architecture showing thin ectosome and ill-formed choanosomal architecture. Cyclacanthia rethahofmeyri sp. nov., holotype SAMC-A090895: D. Preserved specimen; E, F. Isospinodiscorhabds; G. Large isospinodiscorhabd; H. Skeletal architecture showing thick ectosome and and ill-formed choanosomal architecture.