Cyclacanthia rethahofmeyri Samaai, Kelly, Payne

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 : 435-437

Cyclacanthia rethahofmeyri Samaai, Kelly, Payne and Ngwakum sp. nov.

( Fig. 15B , Tables 6, 7)

Material examined. Holotype SAMC-A090895, Amathole region Stn 3872, Eastern Cape, 32.950° S, 28.066° E, 40.5 m, RV Ellen Khuzwayo, collected by R. Payne, dredge, 31 Aug 2016 . Paratypes. SAMC-A090896, Amathole region Stn 3737, Eastern Cape, 32.751° S, 28,415° E, 31 m, RV Ellen Khuzwayo, collected by R. Payne, dredge, 23 Feb 2016 ; SAMC-A090897, SAMC-A090898, SAMC-A090899, Amathole region Stn 3832, Eastern Cape, 32.759° S, 28.410° E, 45 m, RV Ellen Khuzwayo, collected by R. Payne, dredge, 27 Aug 2016 .

Type locality. Amathole region, off East London , Eastern Cape .

Distribution. Amathole region, off East London, 40.5 m.

Description. Shape varies from either flattened low lying hemispherical (flattened), ranging from 24 mm long by 24 mm wide by 6 mm thick to hemispherical sponges, 13 mm long by 34 mm wide by 27 mm thick ( Fig. 15D ). Surface undulating but smooth, with volcano-shaped oscules, 5 mm high by 3 mm wide at base, 1 mm at apex being closely packed (5mm apart), and a few nodular truncate areolate porefields, 3 mm high by 3 mm wide, with no poral membrane covering the opening. Texture firm, rubbery and tough. Medium to barely compressible, difficult to tear or break. Colour in life either black, dark green/black or dark brown; in preservative dark green ( Fig. 15D ). Green exudate visible, no smell.

Skeleton. The choanosomal skeleton forms an irregular polygonal reticulation formed by wispy tracts of smooth styles ( Fig. 15H ). The tracts range in width from 85 –150 μm in thickness, and form meshes that are 195 μm wide. Within the inner choanosome, tracts diverge towards the surface and are 172–205 μm wide. Interstitial spicules are abundant. The ectosome has a palisade of densely packed interlocking anisodiscorhabds, which are absent from the surface structures. The paratangential layer beneath the palisade is approximately 320 μm deep, and this extends into the oscular fistules.

Spicules. Megascleres are anisostyles in one size category: Large, thick, smooth, straight, occasionally sinuous, centrally thickened, narrow proximal region, fusiform: 696 (480–796) × 18 μm. Microscleres are isospinodiscorhabds I ( Fig. 15E, F ) with 50% of microscleres either having three or two whorls. In some spicules the median whorl is absent or rudimentary. The manubrium is identical to the apical whorl. The median whorl is equidistant from both apical whorl and manubrium, but smaller and shorter: 49 (38–60) μm. Large isospinodiscorhabds II ( Fig. 15G ) with two whorls, 75 (64–88) × 15 (15) μm.

Substratum, depth range and ecology. Occurs off East London, Amathole region at a depth range of 30–42 m.

DNA sequence data. We sequenced partial COI of collected material from different localities; GenBank accession numbers: COI MK153269 – MK153271 ; MK016476 .

Etymology. The species name rethahofmeyri is given in memory of Emeritus Professor Dr Retha Hofmeyr who joined the Zoology Department at the University of Western Cape in 1974 and served as Head of Department from 1991 to 1992 before she passed away in 2020. Retha will always be cherished and remembered for her kindness and encouragement of her students and staff.

Remarks. Cyclacanthia rethahofmeyri sp. nov. have acanthose isospinodiscorhabds as microscleres ( Fig. 14 ) and conforms to the general skeletal characteristics of the genus. The examination of this material revealed the presence of a second category of large isospinodiscorhabds ( Fig. 15G, a spicule not present in any other Cyclacanthia species described to date ( Samaai et al. 2004). The definition of Cyclacanthia has been expanded to include species with a 2 nd category of isospinorhabds. The COI sequences of the Cyclacanthia specimens was clearly separated from Tsitsikamma and formed one, strongly supported phylogenetic cluster characterised by a single distinct haplotype ( Fig. 6 ). Table 7 highlights the morphological characters of the different Cyclacanthia species and figure 14 shows the different types of isospinodiscorhabds. The family Latrunculiidae is monophyletic as indicated by the COI phylogeny ( Fig. 6 ).

Figures

FIGURE 6. Phylogram constructed from COI sequences showing family Latrunculiidae, as represented by Tsitsikamma, Latrunculia, Cyclacanthia and Sceptrella specimens, as monophyletic and resolved as separate to Tsitsikamma.

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.