Tsitsikamma (Clavicaulis subgen. nov.) beukesi Samaai, Kelly, Payne and Ngwakum sp. nov.

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 : 431-432

Tsitsikamma (Clavicaulis subgen. nov.) beukesi Samaai, Kelly, Payne and Ngwakum sp. nov.

( Fig. 13 , Table 1, 5)

Material examined. Holotype SAMC-A090892, Amathole region Stn 3876, Eastern Cape, 33.285° S, 27.909° E, 103 m, RV Ellen Khuzwayo, collected by R. Payne, dredge, 02 Sep 2016.

Type locality. Amathole , Eastern Cape Province, South Africa .

Distribution. Amathole region off East London.

Description. Sponge pedunculate, stalk length 30 mm, bulb area 45 mm diameter, stalk base 10 mm wide and stalk width 5 mm ( Fig. 13A ) with overall length of sponge 81 mm high. A very tough leathery purse surrounds a much softer choanosome that pulls away from the outer case upon collection. Surface undulating but smooth with cauliform areolate porefields, 2 mm diameter, 5 mm high. Oscules not visible in preserved specimens ( Fig. 13A ). Texture tough and rubbery. Barely compressible, tears so-so and breaks hard. No spicules or fibres. Colour in life is dark olive-green brown; in preservative the ectosome is brown, the choanosome is dark brown. Brown-green exudate.

Skeleton. The overall architecture is purse-like, consisting of a thick ‘purse’ of tangential megascleres (the ectosome) surrounding a much softer choanosome containing an irregular reticulation of wispy tracts of anisostyles ( Fig. 13C ). The choanosome detaches and falls away from the ectosomal purse in preservative. The choanosomal tracts range in width from 30–45 μm thick and form meshes that are elliptical in cross section and 120 μm wide. Microscleres are abundant throughout the choanosome and form an irregular palisade of oblique or erect microscleres, below which is a dense feltwork of tangential and paratangential styles approximately 144–173 μm deep ( Fig. 13C ).

Spicules ( Table 1, 5; Fig. 13 ). Megascleres are anisostyles, in two size categories: (1) Large, straight or slightly sinuous, thickened centrally, fusiform, 740 (710–787) × 14 (14) μm; (2) straight or slightly sinuous, thickened centrally, fusiform: 622 (537–662) × 14 (19) μm ( Table 1, 5). Microscleres are isochiadiscorhabds with three whorls of cylindrical, conical tubercles, medium whorl shorter, the apex of each tubercular projection is acanthose. Immature spicules have medium whorl present: 35 (28–38) × 5 (5) μm ( Fig. 13B ; Table 5).

Substratum, depth range and ecology. Rocky reef and sandy plains between a depth of 50–100 m depth.

DNA sequence data. No COI sequences.

Etymology. This species is named after Prof. Denzil Beukes, in recognition for his contribution to the taxonomy and marine natural products chemistry of South African sponges, especially the family Latrunculiidae .

Remarks. The live specimen of T. (C.) beukesi subgen. et sp. nov. is dark olive-green brown in colour with a smooth surface along with cauliform areolate porefields, unlike T. (C. subgen. nov.) pedunculata , where the surface is crowded with small, button-shaped oscules and with numerous circular fungiform areolate porefields. Tsitsikamma (C. subgen. nov.) pedunculata is also extremely resilient and leathery with a thick ectosome and salmon pink to pinkish brown in colour. The preserved specimen of T. (C.) beukesi subgen. et sp. nov. is a uniform brown colour with the choanosome being dark brown.

In addition, Tsitsikamma . (C.) beukesi subgen. et sp. nov. differs from Tsitsikamma (C. subgen. nov.) pedunculata in the following characteristics: 1) Tsitsikamma (C. subgen. nov.) pedunculata differs considerably from Tsitsikamma (C.) beukesi subgen. et sp. nov. in the texture and thickness of the ectosome, internal tracts and surface structures which is smooth and undulating in Tsitsikamma (C.) beukesi subgen. et sp. nov.; 2) Tsitsikamma . (C.) beukesi subgen. et sp. nov. has larger, thicker anisostyles [thick 740 (710–787) × 14 (14) μm; thin 622 (537–662) × 14 (19) μm] than Tsitsikamma (C. subgen. nov.) pedunculata [thick 684 (591–728) × 16 μm; thin 536 (500–555) µm], and the isochiadiscorhabds are larger than those found in T. (C. subgen. nov.) pedunculata [29 (27–30) × 7 µm]; Tsitsikamma . (C.) beukesi subgen. et sp. nov. [35 (28–38) × 5 (5) μm] (see Table 1); 3) Tsitsikamma . (C.) madiba subgen. et sp. nov. have isochiadiscorhabds with three whorls of long cylindrical, conical tubercles, and well-developed manubrium, as opposed to T. (C. subgen. nov.) pedunculata having two whorls of cylindrical conical spines; 5) Tsitsikamma (C.) beukesi subgen. et sp. nov. is recorded from the Amathole region, where the shelf is narrow and Agulhas current prevalent, while Tsitsikamma (C. subgen. nov.) pedunculata is recorded from Algoa Bay.

Tsitsikamma (C.) beukesi subgen. et sp. nov. can also be compared to T. (C.) Madiba subgen. et sp. nov.: (1) T. (C.) madiba subgen. et sp. nov. is dark green to dark green brown coloured in situ, ovate, purse-like, not stalked, and has small, button-shaped oscules and cauliform areolate porefields; 2) T. (C.) madiba subgen. et sp. nov. has a very tough leathery purse like in T. (C. subgen. nov.) pedunculata ; 3) Tsitsikamma . (C.) beukesi subgen. et sp. nov. have on average similar size range anisostyles (thick 740 (710–787) × 14 (14) μm; thin 622 (537–662) × 14 (19) μm) to T. (C.) madiba subgen. et sp. nov. (thick 737 (681–758) × 19 (19) μm; thin 612 (576–672) × 19 (19) μm), but the isochiadiscorhabds are smaller than those found in Tsitsikamma (C.) beukesi subgen. et sp. nov. [35 (28–38) × 5 (5) μm]; T. (C.) madiba subgen. et sp. nov. [32 (28–36) × 5 (5) μm] (see Table 4). 4) Tsitsikamma (C.) beukesi subgen. et sp. nov. have isochiadiscorhabds with three whorls of long cylindrical, conical tubercles, and well-developed manubrium, oppose to T. (C.) madiba subgen. et sp. nov. having two whorls of cylindrical conical spines.

Like T. (C. subgen. nov.) michaeli , T. (C.) beukesi subgen. et sp. nov., is purse-like, with isochiadiscorhabds having three whorls of cylindrical, conical tubercles. Defining the differences between T. (C.) beukesi subgen. et sp. nov. and T. (C. subgen. nov.) michaeli is more challenging. Most apparent is the surface morphology. The surface of T. (C. subgen. nov.) michaeli are dominated by small short tube-shaped oscula, and large stalked cauliform porefields, with the porefields spilling over the supporting stalk (Parker-Nance et al. 2019). In contrast, T. (C.) beukesi subgen. et sp. nov. has very few oscules and cauliform porefields visible giving the surface a smooth appearance.

Tsitsikamma (C. subgen. nov.) michaeli has a very tough leathery purse like appearance and the species does not have a stalk, although the basal attachment area of Tsitsikamma (C. subgen. nov.) michaeli is reinforced by a thickening of the ectosome (Parker-Nance et al. 2019). Tsitsikamma . (C.) beukesi subgen. et sp. nov. is stalked. Tsitsikamma (C.) beukesi subgen. et sp. nov. have on average smaller and thinner size range anisostyles (thick 740 (710–787) × 14 (14) μm; thin 622 (537–662) × 14 (19) μm) to T. (C. subgen. nov.) michaeli (thick 713 (537–935) × 21 (12–30) μm; thin 622 (439–769) × 9 (4–13) μm). The isochiadiscorhabds of Tsitsikamma (C.) beukesi subgen. et sp. nov. [35 (28–38) × 5 (5) μm] are smaller than those found in T. (C. subgen. nov.) michaeli [38 (34–44) μm] (see Table 4). T. (C. subgen. nov.) michaeli have isochiadiscorhabds with three or four whorls and the acanthose tubercles are arranged in sets of two to four, radiating from the terminal ends (Parker-Nance et. al. 2019). Tsitsikamma (C. subgen. nov.) michaeli is often encrusted by a yellow species of Mycale (Mycale) also found on the surface of T. (C. subgen. nov.) pedunculata . Tsitsikamma (C.) beukesi subgen. et sp. nov. have isochiadiscorhabds with three whorls of long cylindrical, conical tubercles, and well-developed manubrium similar in size and structure to the apical whorl. The acanthose tubercles are well defined and arranged in sets of three on the manubrium and apical whorls and singular along the medium whorl.

In summary, it is the general appearance of Tsitsikamma . (C.) beukesi subgen. et sp. nov., the shape and abundance of the porefields, and smaller size of the oscula, the colour, both in life and preserved, the shorter in average styles and isochiadiscorhabds, the slight difference in the arrangement of the acanthose tubercles, the similar appearance and size of the microsclere manubrium and apical whorl, the slightly thinner ectosome, that contribute as a whole to a species that is distinctly different in appearance from T. (C. subgen. nov.) pedunculata , T. (C.) madiba subgen. et sp. nov. and T. (C. subgen. nov.) michaeli .

Figures

FIGURE 13. Tsitsikamma (C.) beukesi sp. nov., holotype SAMC-A090892: A. Preserved holotype; B. Isochiadiscorhabd; C. Skeletal architecture showing thin ectosome, layer of erect isochiadiscorhabds and ill-formed choanosomal skeleton.