Leucandra rudifera ( Poléjaeff, 1883 )

Pereira, Sara Emilly, Azevedo, Fernanda, Hajdu, Eduardo, Cavalcanti, Fernanda F. & Klautau, Michelle, 2025, Calcareous sponges (Porifera, Calcarea) from São Sebastião, São Paulo: new species and new records in two marine protected areas of Southeastern Brazil Ecoregion, Zootaxa 5688 (1), pp. 1-107 : 54-61

Leucandra rudifera ( Poléjaeff, 1883)

( Figs. 28–32 ; Table 13)

Synonyms: Leuconia rudifera — Poléjaeff 1883: 58; Burton 1956: 117; Burton 1963: 292. Leucandra rudifera — Thacker 1908: 773; Moraes et al. 2006: 167; Muricy et al. 2011: 28. Leucandra globosa — Muricy et al. 1991: 1187; Muricy & Silva 1999: 160.

Type locality: Bermuda, British Overseas Territory , North Atlantic Ocean .

Material examined: MNRJ30132 , Búzios Island , Ilhabela, São Paulo State, Brazil, depth 8 m, coll. E. Hajdu & M. Ventura, 30/IV/2002 . UFRJPOR9077, Sumítica Island , Ilhabela, São Paulo State, Brazil, depth 9 m, coll. F. F. Cavalcanti & V. Padula, 02/XII/2008 .

Comparative material examined: Holotype of Leucandra rudifera — BMNH.1884.4.22.42-44 (slides), Bermuda, Challenger Exp., station 36, 23/IV/1873, depth 59 m.

Additional material examined: BMNH.1948.3.8.6 (slides), Atlantide Exp. Western Africa, station 151, depth 65 m. MNRJ5581 , Comprida Island , northern shore, Cagarras Archipelago, Rio de Janeiro, RJ, Brazil, depth 10– 12 m, coll. L. Monteiro, 13/III/2002 . MNRJ8080 , Comprida Island , northern shore, Cagarras Archipelago, RJ, Brazil, depth 10–12 m, coll. L. Monteiro, 15/II/2004 . MNRJ8994 , 8999 , Palmas Island , southern shore, Cagarras Archipelago, RJ, Brazil, depth 12 m, coll. F. Moraes & L. Monteiro, 23/II/2005 . MNRJ7390 B, first pool of Parcel do Túnel , Trindade Island, Espírito Santo, Brazil, depth 2.5 m, coll. F. Moraes, 19/VIII/2003 .

Colour: Beige or white in life and in ethanol ( Fig. 28A ).

Morphology and anatomy: Oval sponge with a single apical osculum surrounded by a crown of trichoxeas ( Fig. 28A–C ). The consistency is friable. Diactines and microdiactines protrude through the surface, making it hispid ( Fig. 28A ). The atrial cavity is reduced and hispid due to the apical actines of the atrial tetractines and atrial grapnel spicules. The aquiferous system is leuconoid, with subcortical lacunae extending transversely from the surface deep into the choanosome ( Figs. 28D ; 29A ). Additionally, wide exhalant canals are present, appearing as invaginations of the atrium ( Figs. 28D ; 29A ).

The oscular crown is formed by trichoxeas and supported by T-shaped tetractines and few triactines ( Fig. 28B, C ). The cortical skeleton is composed of a tangential layer of triactines and a few tetractines, whose apical actines project into the choanosome ( Fig. 29B, C ). Large diactines protrude perpendicularly or obliquely through the surface, reaching about one-third of the choanosome ( Figs. 28D ; 29A ). Trichoxeas and cortical microdiactines are also abundant, occurring singly or in tufts, arranged tangentially or perpendicularly to the cortex ( Fig. 30A, B ). Although there is no well-defined subcortical skeleton, pseudosagittal triactines occur sparsely in this region ( Fig. 29D ). The choanosomal skeleton consists of triactines and is predominantly disorganised, however, there are traces of articulation near the external surface, where some of the choanosomal triactines are arranged in layers, with the unpaired actine pointing to the cortex ( Fig. 29A ). The choanosomal canals are lined by tetractines and triactines, the former more abundant ( Fig. 29E ). The atrial skeleton is mainly composed of tetractines, very rare triactines and grapnel spicules ( Figs. 29F ; 30C ). A single pentactine was observed in the atrium ( Fig. 29F , inset). The grapnel spicules are arranged tangentially to the atrial surface, oriented in various directions, forming a reticulation that covers the atrial tetractines and lines the entire atrial cavity ( Fig. 30C, D ). Additionally, they are organised into tufts projecting into the atrium, often arranged around the apical actines of the atrial tetractines ( Figs. 29F ; 30E, F ).

Spicules ( Table 13):

Trichoxeas: Long, thin, cylindrical, with sharp tips.

Diactines: Slightly curved and fusiform, with both tips sharp ( Fig. 31A ). Size: 1,345.0 (±473.7)/44.5 (±7.2) µm.

Cortical microdiactines: Straight or slightly curved. The distal tip is harpoon-shaped and spined, while the proximal tip is sharp, smooth and usually thicker. A ring-like swelling is present near the distal tip, bordered by spines directed towards the proximal end. The spines distributed along each side of the spicule point towards the different tips ( Fig. 32A ). Size: 85.1 (±14.8)/2.9 (±2.3) µm.

Cortical triactines and tetractines: Slightly sagittal, variable in size. Basal actines are conical to slightly conical and sharp. The unpaired actine is straight and a little shorter than the paired ones, which are often undulated and outwardly curved ( Fig. 31B, C ). The apical actine of the tetractines is straight or slightly undulated, conical, sharp and variable in size. Triactines size: paired—218.0 (±61.2)/14.8 (±4.4) µm; unpaired—197.5 (±55.0)/15.9 (±4.2) µm. Tetractines size: paired—228.3 (±64.3)/15.8 (±4.7) µm; unpaired—184.8 (±69.9)/17.3 (±5.4) µm; apical—160.1 (±91.5)/16.2 (±4.8) µm.

Subcortical triactines: Pseudosagittal. Actines are slightly conical, with sharp tips. The unpaired actine is straight and frequently shorter than the paired ones, which are curved ( Fig. 31D ). Size: paired 1—268.6 (±63.7)/23.5 (±5.0) µm; paired 2—347.3 (±90.1)/23.0 (±4.9) µm; unpaired—231.4 (±65.8)/24.8 (±4.7) µm.

Choanosomal triactines: Large, slightly sagittal and variable in size, sometimes with all actines different in length. Actines are conical, with sharp tips. The paired actines are straight or slightly curved and longer than the unpaired one ( Fig. 31E ). Size: paired—414.8 (±82.6)/32.5 (±5.5) µm; unpaired—361.0 (±59.2)/34.2 (±5.0) µm.

Triactines and tetractines of the canals: Sagittal, but variable in shape and size. Basal actines are cylindrical to slightly conical, with sharp tips. Some are slightly sagittal and large, with the paired actines outwardly curved, others are more sagittal and smaller, with the paired actines slightly curved towards the unpaired one, which is much shorter ( Fig. 31F ). The apical actine of the tetractines is smooth, curved, conical and sharp. Triactines size: paired—156.5 (±46.5)/14.2 (±2.9) µm; unpaired—170.0 (±56.7)/16.3 (±2.9) µm. Tetractines size: paired—243.2 (±56.5)/17.3 (±5.4) µm; unpaired—196.6 (±80.3)/19.2 (±6.2) µm; apical—72.6 (±31.7)/10.5 (±4.4) µm.

Atrial triactines and tetractines: Strongly sagittal. Basal actines are cylindrical, with sharp tips. The unpaired actine is straight or undulated and shorter than the paired ones, which are straight or slightly curved outwardly ( Fig. 31G ). The apical actine of the tetractines is smooth, curved, conical, sharp and can be as long as the unpaired actine. Triactines size: paired—199.2 (±37.3)/9.8 (±0.9) µm; unpaired—94.2 (±9.7)/9.8 (±0.9) µm. Tetractines size: paired—241.3 (±51.4)/10.3 (±1.1) µm; unpaired—120.3 (±43.3)/10.2 (±1.4) µm; apical—93.3 (±30.7)/8.1 (±1.0) µm.

Grapnel spicules: They are tetractines whose basal actines are similar to short hooks. The apical actine is very long and sinuous, with spines distributed along most of its length. It tapers in the middle and gradually swells near the tip, which is sharp and smooth. Both the basal actines (hooks) and spines are directed towards the tip of the apical actine ( Fig. 32B ). Size: 58.1 (±12.0)/1.3 (±0.0) µm.

Ecology: Species collected on rocky surfaces, exposed to sunlight and inside caves. No associated organisms were found.

Geographic distribution: Bermuda ecoregion— Bermuda Islands, North Atlantic Ocean ( Poléjaeff 1883), British Overseas Territory. Cape Verde ecoregion— Cape Verde Archipelago ( Thacker 1908), Western Africa. Gulf of Guinea West ecoregion— Guinea-Bissau ( Burton 1956; uncertain), Western Africa. Namaqua ecoregion— South Africa ( Burton 1963; uncertain). Trindade and Martin Vaz Islands ecoregion—Trindade Island, Espírito Santo State ( Moraes et al. 2006), Brazil. Southeastern Brazil ecoregion—Arraial do Cabo and Cagarras Archipelago ( Muricy et al. 1991; Muricy & Silva 1999; present study), Rio de Janeiro State; Búzios and Sumítica Islands (Ilhabela), São Paulo State (present study), Brazil.

Remarks: Leucandra rudifera ( Poléjaeff, 1883) was originally described from Bermuda and later recorded to the Cape Verde archipelago ( Thacker 1908) and to the western and southern coasts of Africa ( Burton 1956, 1963). The species was also reported to the Brazilian coast: Arraial do Cabo (Rio de Janeiro), as Leucandra globosa Sarà, 1951 ( Muricy et al. 1991; Muricy & Silva 1999; see also Muricy et al. 2011), and Trindade Island (Espírito Santo) ( Moraes et al. 2006).

We had the opportunity to examine the slides of the holotype of L. rudifera , along with slides of the Western African specimens, the specimen from Trindade Island ( Moraes et al. 2006), and additional Brazilian specimens from Cagarras Archipelago, Rio de Janeiro (unpublished). Our analysis of the holotype confirms the identification of our specimens as L. rudifera . Indeed, we observed in the holotype few cortical tetractines and subcortical pseudosagittal triactines, as well as rare atrial triactines, spicule categories not mentioned in the original description, and shared with our specimens. Furthermore, the cortical microdiactines of the holotype are harpoon-shaped and spined, like those of the Brazilian specimens—another feature not mentioned in the original description of L. rudifera .

It is worth noting that in the specimens from Rio de Janeiro, cortical tetractines are comparatively rarer, and they were not found in the specimen from Trindade Island. This suggests that the abundance, and possibly even the presence, of cortical tetractines in L. rudifera may be subject to intraspecific variation. This is the main reason we refrained from transferring L. rudifera to Leucandrilla . Although the presence of cortical tetractines, subcortical pseudosagittal triactines, and traces of articulation in the choanoskeleton are part of the diagnosis of Leucandrilla ( Cavalcanti et al. 2019) , in two species of the genus (including the type species) redescribed by Cavalcanti et al. (2019), the cortical tetractines are abundant, not rare (or apparently absent) as in Leucandra rudifera .

Regarding the specimens from Western Africa identified as L. rudifera by Burton (1956), we did not observe grapnel spicules in their skeletal sections. In all other features, these specimens match the holotype and the Brazilian ones. However, the absence of grapnel spicules raises the possibility that these specimens may represent a different species. Additionally, Burton (1963) identified a sponge from South Africa as L. rudifera without providing a description. Therefore, we consider the records of L. rudifera from Western and South Africa as uncertain for now.

The presence of grapnel spicules in the atrium is considered the main diagnostic feature of L. rudifera . However, Leucandra globosa ( Sarà, 1951) , described from the Mediterranean Sea, also bears this spicule type. Leucandra globosa has a spicular composition similar to that of L. rudifera and it is possible that they are synonyms ( Muricy et al. 2011). Nevertheless, we identified the present specimens as L. rudifera because this species is from the Western Atlantic and has priority over L. globosa , as the former was described in 1883 by Poléjaeff.

We produced the first C-LSU sequence for L. rudifera , which was identical to that of a specimen from St. Helena , South Atlantic, identified as Paraleucilla sp. 1 by Alvizu et al. (2018). Hence, this material should be re-examined in future studies, because it is possible that Paraleucilla sp. 1 ( Alvizu et al. 2018) corresponds to L. rudifera .

Figures

FIGURE 28. Leucandra rudifera (MNRJ30132). A. Preserved specimen. B. Oscular crown. C. Skeleton of the osculum, showing trichoxeas, triactines and tetractines. D. Cross section of the body wall. cx = cortex, at = atrium, c = choanosomal canals, asterisks = lacunae.

FIGURE 29. Leucandra rudifera (MNRJ30132). A. Cross section of the body wall. B. Tangential section of the cortex (arrowheads point to tetractines). C. Cortical tetractine. D. Subcortical triactine (arrowhead). E. Choanosomal canal. F. Atrial skeleton in cross section (atrial pentactine in the inset). cx = cortex, at = atrium, c = choanosomal canals, asterisks = lacunae.

FIGURE 30. Leucandra rudifera (MNRJ30132) in SEM. (A–B) Cortical skeleton. A. Trichoxeas and cortical microdiactines lying on the surface. B. Cortical microdiactines protruding through the surface. (C–F) Atrial skeleton. C. Mesh of grapnel spicules covering the atrial tetractines. D. Group of atrial grapnel spicules. E. Mesh of grapnel spicules and apical actines of the atrial tetractines. F. Grapnel spicules arranged around the apical actines of the atrial tetractines.

FIGURE 31. Leucandra rudifera (MNRJ30132). A. Diactines. B. Cortical triactines. C. Cortical tetractine. D. Subcortical triactine. E. Choanosomal triactines. F. Triactines and tetractines of the canals. G. Atrial tetractine.

FIGURE 32. Leucandra rudifera (MNRJ30132). A. Cortical microdiactines. B. Grapnel spicule.