Placospongia ruetzleri van Soest, 2017

Sandes, Joana, Moraes, Fernando & Muricy, Guilherme, 2024, Taxonomy of Placospongia Gray, 1867 from Northern and Northeastern Brazil, with description of two new species (Porifera: Demospongiae: Clionaida), Zootaxa 5405 (4), pp. 495-525 : 509-513

Placospongia ruetzleri van Soest, 2017

( Figs. 4 and 7–9 ; Tables 2–3 , 5 and 7 )

Synonyms

Placospongia ruetzleri van Soest, 2017: 173 ; Mácola & Menegola 2021: 12 ; Ugalde et al. 2021:30 ; Bettcher et al. 2023: 450 (in part).

Placospongia carinata sensu Little 1963: 56 ; Coelho & Mello-Leitão 1978; Pulitzer-Finali 1986: 100 (non Geodia carinata Bowerbank, 1858 ).

Placospongia intermedia sensu Muricy & Moraes 1998: 215 ; Jimenez et al. (2004): 88 (non Placospongia intermedia Sollas, 1888 ).

Placospongia sp. 1 sensu van Soest 2009: 11.

Material examined. UFRJPOR 561, off Amazon River mouth , Pará State, N Brazil (0º22’59.999”S, 47º16’0.998”W), 31 m depth, leg. Navio Oceanográfico Almirante Saldanha (N.O.A.S.), Station 1889, 26 April 1968 (= Placospongia carinata sensu Coelho & Mello-Leitão 1978 ) ; UFRJPOR 4848, off Amazon River mouth , Pará State, N Brazil (0º25’0.003”S, 47º16’59.999”W), leg. Navio Oceanográfico Almirante Saldanha (N.O.A.S.), Station 1763, 28 November 1965 ; MNRJ 3018 , Mamucabinha reefs, Tamandaré city, Pernambuco State, NE Brasil (8º47’15.015”S, 35º6’13.968”W), intertidal, coll. Guilherme Muricy, June 1997 (= Placospongia intermedia sensu Muricy & Moraes 1998 ) ; MNRJ 6079 , Flexeiras beach, Trairi city, Ceará State, NE Brazil (3º12’48.168”S, 39º15’13.572”W), intertidal, 10 July 2002 (= Placospongia intermedia sensu Jimenez et al. 2004 ) ; MNRJ 23227 , Baixa Funda reef, Pirangi do Sul beach, Nísia Floresta city, Rio Grande do Norte State, NE Brazil (5º56’38.74128”S, 35º06’58.57128”W), 10 m depth, colls. Guilherme Muricy & Joana Sandes, 06 March 2020 ; MNRJ 29236 , Carnaubinha beach , Luis Correia city, Piauí State, NE Brazil (02º54’19.56”S, 41º34’35.26”W), intertidal, colls. Bruno Annunziata, Francisco Artur Silva Filho & Maura Rejane de A. Mendes, 8 September 2022 ; MNRJ 29237 , Carnaubinha beach , Luis Correia city, Piauí State, NE Brazil (02º54’19.56”S, 41º34’35.26”W), intertidal, colls. Bruno Annunziata, Francisco Artur Silva Filho & Maura Rejane de A. Mendes, 10 September 2022 .

Description ( Fig. 7a–d ). Shape thick encrusting, with approximately 3.0–7.0 × 1.0–4.0 × 0.5–2.0 cm (lenght × width × thickness). The surface is smooth and divided into cortical plates of polygonal shape, separated by pore-bearing grooves and ridges. The consistency is hard. The external color in vivo is reddish-brown ( Fig. 7a ) to purplish brown ( Fig. 7b ). In ethanol, the external color is light ( Fig. 7c ) to dark brown ( Fig. 7d ), the internal color is cream and the grooves are light brown.

Skeleton ( Fig. 8a–c ). The cortex is 730–1,020 µm thick, distinct from the choanosome ( Fig. 8a ). The inner layer of the cortex is densely packed with selenasters and the outer layer is formed by scattered acanthomicrorhabds. Small tylostyles occur in the cortical region together with acanthomicrorhabds, through the aquiferous openings, which are devoid of selenasters ( Fig. 8b ). The choanosomal skeleton is formed by tracts of tylostyle 200–310 µm thick, which run obliquely or perpendicularly from the substrate to the cortex ( Fig. 8a ). The spirasters occur abundantly in the choanosome ( Fig. 8c ), often lining the choanosomal openings. Mature selenasters, immature selenasters and acanthomicrorhabds are scattered in the choanosome among the bundles of tylostyles. At the base there is a dense layer of selenasters, 550–850 µm thick ( Fig. 8a ).

Megascleres ( Fig. 9a–d ; Tab. 5 ). Two categories of tylostyles. Tylostyles I are large, choanosomal, with blunt ends and rounded tyle: 490–888–1170 / 6–14–20 µm, tyle 10–17–24 µm width ( Fig. 9a–b ). Tylostyles II are small, cortical, with sharp ends and rounded tyle: 140–324–570 / 2–8–15 µm, tyle 4–9–18 µm width ( Fig. 9c–d ).

Microscleres ( Fig. 9e–i ; Tab. 5 ). Mature selenasters are circular to oval, with fused spines forming rounded or polygonal plates: total size 32–69–88 / 20–54–73 µm, hilum 7–10 µm in diameter ( Fig. 9e ). Three types of immature selenasters: type I are straight, slender, spiny, bearing spines concentrated at the ends of the shaft: 20–23–28 / 2–4–8 µm; type II are elongated, stout, with large and numerous spines: 25–28–35 / 12–14–15 µm ( Fig. 9f ); type III are oval, stout, with spines very closely set, but still recognizable in their individuality: 40–45–50 / 25–32–40 µm. Immature selenasters types II and III are more abundant than type I. Spirasters ( Fig. 9g ) are microspined, sometimes amphiaster-like ( Fig. 9h ), with only one spiral turn and long rays disposed along the shaft or concentrated at both ends; some rays are branched into secondary spines near the extremity: 12–19–25 µm. Acanthomicrorhabds are small, stout, with rounded ends, occasionally with one or two turns: 5–9–15 µm ( Fig. 9i ).

Habitat. This species was found on sandy bottom on the Guyana Shelf, at 25–34 m depth (van Soest 2017) and off the Amazon River mouth at 31 m depth ( Coelho & Mello-Leitão 1978, as P. carinata ). In Northeast Brazil, it is abundant in reef environments, occurring from the intertidal zone to 10 m depth, usually under boulders ( Muricy & Moraes 1998; Jimenez et al. (2004); Mácola & Menegola 2021; Bettcher et al. 2023; present study).

Geographical distribution ( Fig. 4 ; Tab. 2 ). Gulf of Mexico ( Little 1963; Ugalde et al. 2021), Jamaica ( Pulitzer-Finali 1986), Suriname (van Soest 2017) and N-NE Brazil: Pará State ( Coelho & Mello-Leitão 1978 as P. carinata ; Muricy et al. 2011; present study), Piauí State (new record, present study), Ceará State ( Jimenez et al. 2004 as P. intermedia ), Rio Grande do Norte State (new record, present study), Pernambuco State ( Muricy & Moraes 1998 as P. intermedia ; Mácola & Menegola 2021), and Bahia State ( Mácola & Menegola 2021; Bettcher et al. 2023).

Taxonomic remarks. Placospongia ruetzleri from the Guyana Shelf and P. carinata from the Pacific Ocean share a similar spiculation, with two categories of tylostyles, rounded selenasters, spirasters/amphiasters, and acanthomicrorhabds (van Soest 2009, 2017; Becking 2013). However, P. ruetzleri is distinguished by the larger size of the tylostyles, the smaller size of the selenasteres, and the more spiraster-like shape of its microscleres, compared to amphiaster-like microscleres in P. carinata ( Tab. 3 ; van Soest 2009, 2017). These differences, along with the large geographic separation, support their distinction at the species level (van Soest 2017).

Placospongia ruetzleri was recently described from Pernambuco and Bahia States, in Northeast Brazil ( Mácola & Menegola 2021; Bettcher et al. 2023). Most Brazilian records of P. carinata ( Hechtel 1976; Coelho & Mello-Leitão 1978, Rua et al. 2006) were tentatively synonymyzed with P. ruetzleri by van Soest (2017), with a question mark due to insufficient information. In contrast, David-Colón et al. (2023) suggested that these records could belong instead to Placospongia soesti David-Colón, Zea & Marín-Casa, 2023 , also with a question mark. The record of P. ruetzleri by Rua et al. (2006) was made in a conference abstract and is not taken in account here. We re-examined the specimen described from Pará State by Coelho & Mello-Leitão (1978) as P. carinata (UFRJPOR 561), including SEM micrographs of the spicules. We concluded that it is indeed co-specific with P. ruetzleri due their great similarity in general spicule size and shape, with presence of oval selenasters, spiraster-like microscleres and acanthomicrorhabds, and absence of spherasters ( Tabs. 3 , 5 and 7 ).

We also examined photographs in light microscopy of the spicules and skeleton of Hechtel’s (1976) specimen of P. carinata from Pernambuco State (YPM 9021) ( Fig. 10a–d ). It has two categories of tylostyles ( Fig. 10a–b ), some of which are bifurcated, with oval to rounded tyles; oval to spherical mature selenasters ( Fig. 10a–c ); rare oxyspherasters ( Fig. 10c ); and possibly also micro-spheroxyasters or spherules ( Fig. 10d ). Immature selenasters, spirasters, amphiasters and acanthomicrorhabds seem to be absent. We concluded that this specimen is not cospecific with either P. carinata , P. ruetzleri or P. soesti , and that it probably belongs instead to a new species yet to be described. We refrain from doing so here due to the lack of SEM micrographs of the spicules, and therefore we propose to leave for now the Brazilian record of P. carinata by Hechtel (1976) as Placospongia sp. , waiting for a full description ( Tab. 7 ).

On the other hand, we revised the specimens recorded by Muricy & Moraes (1998) and Jimenez et al. (2004) as P. intermedia (MNRJ 3018 and 6079, respectively), and concluded that they belong instead to P. ruetzleri due to the general spicule size, the presence of spirasters-like microscleres and acanthomicrorhabds, and the absence of metasters and spherasters, which are characteristic of P. intermedia ( Tabs. 3 , 5 and 7 ).

Figures

FIGURE 4 Distribution of the Placospongia species that occur in Brazil. See Table 2 for localities and references. (1) Placospongia sp. = Placospongia carinata sensu Hechtel (1976); (2) Placospongia sp. = Placospongia carinata sensu Drescher et al. (2005); and (3) Placospongia sp. = Placospongia melobesioides sensu Leonel et al. (2011).

FIGURE 7 Specimens of Placospongia ruetzleri. a MNRJ 29236 (in vivo, reddish-brown color, out of the water in low tide); b MNRJ 23227 (in vivo, purplish brown color); c UFRJPOR 561 (preserved in ethanol); d UFRJPOR 4848 (preserved in ethanol). In situ photographs by Dr. Bruno Annunziata (a) and Dr. Guilherme Muricy (b).

FIGURE 8 Skeletal organization of Placospongia ruetzleri. a Cortex and choanosome in transversal section; b Bundles of tylostyles II running to the aquiferous opening; c Acanthomicrorhabds and spirasters scattered in the choanosome.

FIGURE 9 Spicules of Placospongia ruetzleri. a Tylostyles I; b Tyle and end of tylostyle I; c Tylostyle II; d Tyle and end of tylostyle II; e Mature selenaster; f Immature selenaster of type II; g Spiraster-like microsclere; h Amphiaster-like microsclere; i Acanthomicrorhabds.

FIGURE 10 Spicules of Placospongia carinata sensu Hechtel (1976) (YPM 9021). a Tylostyles I and mature selenasters; b Tylostyle II and mature selenasters; c Rare oxyspherasters (arrows) and mature selenasters; d Micro-spheroxyasters or spherules (arrows). Optical microscopy photographs by Dr. Eric Lazo-Wasem.