Lissodendoryx (Lissodendoryx) ingolei Payne, Samaai & Gibbons, 2025

Payne, Robyn P., Samaai, Toufiek, Janson, Liesl, Kerwath, Sven E. & Gibbons, Mark J., 2025, Eleven new heteroscleromorph Demospongiae (Porifera), and a new record of the tetractinellid Ancorina corticata, from Walters Shoal, a shallow seamount on the Madagascar Ridge in the South West Indian Ocean (SWIO), Zootaxa 5575 (1), pp. 1-56 : 29-32

Lissodendoryx (Lissodendoryx) ingolei Payne, Samaai & Gibbons sp. nov.

urn:lsid:zoobank.org:act:F12369E5-AFB9-40FB-A331-7A4C3E6A8648

Figure 10A–I , Table 8

Material examined. Holotype. SAMC-A096909 (cross-reference TS 2364 & WSL-INV75(5)): Walters Shoal Seamount , coll. RV Algoa , (33°11.2' S; 43°50.7' E), 29 m depth, 30 May 2014 . Paratypes. SAMC-A096910 (cross-reference TS 2365 & WSL-INV75(6)) , SAMC-A096911 (cross-reference TS 2366 & WSL-INV75(7)), SAMC- A096912 (cross-reference TS 2367 & WSL-INV75(8)) , SAMC-A096913 (cross-reference TS 2368 & WSL-INV75(9)): Walters Shoal Seamount , coll. RV Algoa , (33°11.2' S; 43°50.7' E), 29 m depth, 30 May 2014 .

Type locality. Walters Shoal Seamount , south of Madagascar on the Madagascar Ridge , Western Indian Ocean ( Fig. 1 ) .

Description ( Fig. 10A, B ). Massive, ridge-shaped form. Length 13.0 cm, width 7.5 cm and thickness 2.6 cm. Surface smooth and uneven, or markedly coarse with a thin, transparent membrane covering the entire exterior. Oscules (up to 5 mm in size) present, scattered randomly on top of the ridge. Texture firm but spongy, compressible and not easily torn. Colour in situ beige to pale yellow; lab photo light red to orange externally; in preservative, beige.

Skeleton ( Fig. 10C, D ). Choanosomal skeleton comprises a fairly tight-meshed regular renieroid reticulation, with primary fibres ~40 µm across, running obliquely to the surface, composed of spongin and cored by groups of 1–3 smooth styles, diverging in a plumoreticulate manner to ectosome. Secondary fibres ~20–30 µm across, enter the primary fibres at an angle, cored by single styles. Primary and secondary fibres with spongin, without a distinct sheath. Ectosomal skeleton comprises a distinct and continuous palisade of tylotes, perpendicular to and penetrating the surface, sometimes forming radiating bouquets ~150–200 µm deep. Microscleres scattered throughout.

Spiculation ( Table 8 ). Megascleres. Ectosomal tylotes, smooth, straight shafted, with elongated, well-developed heads: 184 (164–197) × 5 (3–6) µm, n = 20 ( Fig. 10E ). Styles smooth, slightly curved with pronounced shaft and hastate end: 130 (117–140) × 6 (4–7) µm, n = 20 ( Fig. 10F ). Microscleres. Sigmas, both C- and S-shaped: 29 (23–32) µm, n = 20 ( Fig. 10G ). Arcuate isochelae in two size classes: I) 24 (22–25) µm, n = 20 ( Fig. 10H ); II) 13 (12–14) µm, n = 20 ( Fig. 10I ).

Substratum, depth range and ecology. Five specimens found on rocky substrata during one dive, often with crinoids as epifauna. Depth range: 29 m.

Etymology. The name ‘ ingolei ’ was given in honour of Dr Baban Ingole, a colleague and friend, from the National Centre for Polar and Ocean Research (NCPOR), Goa, India, for his contributions to our understanding of the deep-water fauna of the South West Indian and Central Indian Ocean Ridges.

Remarks. Lissodendoryx Topsent, 1892 , is a diverse genus with a cosmopolitan distribution, currently comprising 125 valid species as documented in the World Porifera Database ( de Voogd et al. 2024). Five subgenera are recognized in Lissodendoryx since Van Soest (2002) proposed a revised classification for the Coelosphaeridae . These subgenera are distinguished by their skeletal architecture and spicule categories. The new species possess a reticulate choanosomal architecture with a single category of acanthostyles. Therefore, we have classified our species as Lissodendoryx (Lissodendoryx) .

According to the World Porifera Database ( de Voogd et al. 2024), there are currently 69 valid species recognized within Lissodendoryx (Lissodendory x). Of these, only six Lissodendoryx (Lissodendory x) species have been recorded or described from South Africa and the Western Indian Ocean ( de Voogd et al. 2024). These are Lissodendoryx (Lissodendoryx) digitata ( Ridley & Dendy, 1886) , Lissodendoryx (Lissodendoryx) areolata Lévi, 1963 , Lissodendoryx (Lissodendoryx) stephensoni Burton, 1936 ; Lissodendoryx (Lissodendoryx) ternatensis ( Thiele, 1903) , Lissodendoryx (Lissodendoryx) pygmaea ( Burton, 1931) and Lissodendoryx (Lissodendoryx) monticularis Baer, 1906 . The six species are compared to the new species described above.

Lissodendoryx (Lissodendoryx) ingolei Payne, Samaai & Gibbons sp. nov. is distinct from Lissodendoryx (Lissodendoryx) pygmaea ( Burton, 1931) , originally described as Myxilla pygmaea from Natal, South Africa, by having longer megascleres and sigmas (see Table 8 ) and by being massively ridge-shaped, as opposed to being massively flabellate, as described for Lissodendoryx (Lissodendoryx) pygmaea . Burton (1931) noted that Lissodendoryx (Lissodendoryx) pygmaea may be allied with, or identical to, Lissodendoryx (Lissodendoryx) isodictyalis ( Carter, 1882) described from the Caribbean, but disregarded this notion due to the latter species’ distribution. It is highly unlikely that Lissodendoryx (Lissodendoryx) isodictyalis would spread from the Central Atlantic across to the southern WIO. Lissodendoryx (L.) pygmaea was also noted by Lévi (1963, 1969) to resemble the type specimen of Lissodendoryx (Lissodendoryx) ternatensis ( Thiele, 1903) described from Ternate, Indonesia, and a specimen from Vema Seamount (off South Africa), which he described as the latter species. Hofman & Van Soest (1995) indicated that L. (L.) pygmaea may possibly be a closely related, but a separate species to L. (L.) ternatensis , with the latter species having two classes of sigmas.

Lissodendoryx (Lissodendoryx) digitata is described from the Agulhas Bank, located on the south coast of South Africa, and it has a digitate form. According to Ridley and Dendy (1886, 1887), the styles are large and entirely spined, lacking sigmas, and the species possesses only one category of large chelae ( Table 8 ). Additionally, L. (L) digitata differs in having a larger category of tylostyles ( Table 8 ).

Lissodendoryx (Lissodendoryx) areolata Lévi, 1963 , is flabelliform, widening into a blade and attached by a pedunculated base. The species lacks tylotes, and the acanthostyles are almost smooth, with some scattered spines on the head of the spicule ( Lévi, 1963). Overall, the spicule sizes are larger than those found in the new species ( Table 8 ).

Lissodendoryx (Lissodendoryx) stephensoni Burton, 1936 described from the west coast of South Africa has larger sigmas and tylotes than those found in Lissodendoryx (Lissodendoryx) ingolei sp. nov. This species also has only one category of chelae, which are similar in diameter to the larger chelae found in Lissodendoryx (Lissodendoryx) ingolei sp. nov. ( Table 8 ).

Lissodendoryx (Lissodendoryx) monticularis Baer, 1906 described from Zanzibar has small sigmas ( Table 8 ) and only one category of chelae, which are similar in diameter to the small chelae found in Lissodendoryx (Lissodendoryx) ingolei sp. nov.

Lissodendoryx (Lissodendoryx) ternatensis , described from Indonesia, has on average larger styles and sigmas ( Table 8 ) and also has two categories of sigmas. Thiele (1903) noted that a smaller form, half the length of the large sigma, was also observed (see also Hofman & Van Soest, 1995). We consider it highly unlikely that L. (L.) ternatensis would spread from the Central Indo-Pacific to the WIO, South Africa, and across to Vema Seamount in the South Atlantic.

Lissodendoryx (Lissodendoryx) ingolei sp. nov. is distinct from Lissodendoryx (Lissodendoryx) ternatensis based on forementioned differences and the disjunct distribution of L. (L.) ternatensis .

The species reported here is considered well differentiated from other Lissodendoryx (Lissodendoryx) species. Therefore, it appears that there are no species so closely related to the new species that doubts might arise regarding its validity.

Figures

FIGURE 1. A) Map showing the location of Walters Shoal Seamount (red circle) within the bathymetric context of the Western Indian Ocean region (generated using QGIS v.2.6.1; available: qgis.osgeo.org/en/site/). B) Bathymetric map of Walters Shoal Seamount (generated using Surfer 9; Golden Software, available: www.goldensoftware.com). C) Bathymetric map of Walters Shoal Seamount (generated using Surfer 9; Golden Software, available: www.goldensoftware.com), with sled (S), dive (D) and lobster trap (LT) sampling locations.

FIGURE 10. External morphology, skeletal architecture and spicule complement of Lissodendoryx (Lissodendoryx) ingolei sp. nov. A—In situ image. B—Lab photograph of whole-body image of preserved Holotype specimen. C—Skeletal architecture on transverse view showing spongin fibres cored by groups of smooth styles. D—Ectosomal skeleton on transverse view showing palisade of tylotes, perpendicular to and penetrating the surface. E—Tylote. F—Style. G—Sigma (C-shaped). H—Isochela I. I—Isochela II. Scale bars on figure.