Placospongia colombiensis David-Colon, Zea & Marin-Casa 2023
Creators: name: Sandes, Joana
name: Moraes, Fernando
name: Muricy, Guilherme
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Porifera
Demospongiae
Clionaida
Placospongiidae
Placospongia
Placospongia colombiensis

description: Placospongia colombiensis David-Colón, Zea & Marín-Casa, 2023
(Figs. 2–4; Tables 1–3 and 7)
Synonyms
Placospongia colombiensis David-Colón et al. 2023: 514.
Placospongia ruetzleri sensu Bettcher et al. 2023: 450 (in part) (non Placospongia ruetzleri van Soest, 2017).
Material examined. UFPEPOR 2643, UFPEPOR 2684, UFPEPOR 2685, Buraco da Raquel, Fernando de Noronha Archipelago, Pernambuco State, NE Brazil (3°50’03.9”S, 32°23’52.9”W), 1 m depth, colls. Carlos Santos Neto, Thaynã Cavalvanti & Alan Dias, 24 January 2018; MNRJ 24048, Praia do Forte Beach, Mata de São João city, Bahia State, NE Brazil (12º34’5.952”S, 37º55’0.1”W), 0.7 m depth, colls. Guilherme Muricy & Joana Sandes, 22 February 2022; MNRJ 22243, Coroa Alta reef, Santa Cruz Cabrália city, Bahia State, NE Brazil (16º13.200’S, 38º57.038’W), Intertidal, colls. Aline Fioravanso & Marianela Gastaldi, 22 April 2019 (= Placospongia ruetzleri sensu Bettcher et al. 2023).
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Comparative material examined. Placospongia caribica Rützler, Piantoni, van Soest & Días, 2014. Holotype USNM 32873, Columbus Cay cave, Carrie Bow Cay, Belize, 23 m depth, colls. G. Hendler, I. Macintyre, P. Kier, T. Rath & C. Clark, 21 March 1979. Paratype USNM 1228945, Columbus Cay cave, Carrie Bow Cay, Belize, 20 m depth, colls. I. Macintyre & G. Hendler, 26 April 1979.
Diagnosis. Encrusting Placospongia, with orange-brown to orange-yellow color. Megascleres are two categories of tylostyles. Microscleres are oval to bean-shaped mature selenasters, spherasters, elongated spirasters with short rays, short spirasters with verrucose rays that may branch in rosettes, and acanthomicrorhabds with conical spines (modified from David-Colón et al. 2023; additions are highlighted in boldface).
Description (Fig. 2a–b). Shape thinly encrusting, 1.5–4.5 cm wide by 2 mm thick. The surface is composed by smooth polygonal cortical plates separated by pore-bearing grooves. One specimen has a circular osculum 1 mm in diameter, on a cortical plate (Fig. 2a). The color is brownish orange in vivo (Fig. 2a–b). In ethanol, the external color is cream to light brown and the internal one color is cream. Consistency is hard.
Skeleton (Fig. 2c–e). The cortex is dense, 440–640 µm thick, divided in two layers (Fig. 2c–d). The inner layer is densely packed with selenasters and the outer layer is formed by scattered acanthomicrorhabds and spirasters II (Fig. 2d). Small tylostyles, acanthomicrorhabds and spirasters II occur in the cortical region around the aquiferous openings in the grooves, which are devoid of selenasters (Fig. 2c). The choanosomal skeleton is formed by sparse tracts of tylostyles 150–300 µm thick that run obliquely from the substrate to the cortex (Fig. 2c). Mature and immature selenasters, acanthomicrorhabds and spherasters are scattered in the choanosome among the tracts of tylostyles. Spirasters I occur abundantly in the choanosome, often lining the choanosomal cavities (Fig. 2e). The base of the sponge is lined by a dense layer of selenasters, 200–400 µm thick (Fig. 2c).
Megascleres (Fig. 3a–d; Tab. 1). Two categories of tylostyles. Tylostyles I are larger, choanosomal, with blunt ends and rounded tyle: 350–674–930 / 4–9–13 µm, tyle 7–12–18 µm in width (Fig. 3a–b). Tylostyles II are smaller, cortical, with blunt or sharp ends: 120–275–450 / 2–5–9 µm; tyle rounded, 4–7–11 µm in width (Fig. 3c–d).
Microscleres (Fig. 3e–l; Tab. 1). Mature selenasters are oval, bean- or peanut-shaped, in which the spines are all fused, forming rounded or polygonal plates: total size 37–55–68 / 22–35–42 µm, hilum with 8–9–15 µm in diameter (Fig. 3e). There are three types of immature selenasters: (I) straight, slender, spiny, with spines concentrated on the ends of the shafts: 20–22–25 / 5–6–8 µm; (II) elongated or dumbbell-shaped like, with large and numerous spines: 22–30–35 / 8–11–13 µm (Fig. 3f); and (III) oval or peanut shaped, stout, with spines very closely set but still recognizable in their individuality: 35–40–45 / 15–22–25 µm (Fig. 3g). Spherasters are smooth or rugose, with short and conical rays: 10–14–20 µm in diameter (Fig. 3h). Spirasters I are long and thin, smooth or microspined, with one or two spiral turns and short rays disposed along the shaft: 12–17–30 µm (Fig. 3i); spirasters II are shorter, with one or two turns in length, with clustered (Fig. 3j) or verrucose rays (Fig. 3k): 4–7–10 µm. Acanthomicrorhabds are short, with rounded ends and conical spines, occasionally with one or two turns (Fig. 3l): 4–7–10 µm in length.
Habitat. The Caribbean populations occurs in crevices on rocky shores and coral reefs, at 1–23 m depth (David-Colón et al. 2023). The Brazilian specimens were found under boulders in tide pools, 0.7–1.0 m depth.
Geographical distribution (Fig. 4; Tab. 2). Caribbean Sea: Colombia and Bahamas (David-Colón et al. 2023). Northeast Brazil: Fernando de Noronha Archipelago (Pernambuco State) (new record, present study) and Bahia State (new record, present study; Bettcher et al. 2023 as P. ruetzleri, in part).
Taxonomic remarks. The spiculation of one specimen identified as P. ruetzleri by Bettcher et al. (2023) correspond instead to Placospongia colombiensis (Tab. 7). Brazilian and Colombian specimens of P. colombiensis are very similar in spicule shape and size, with two categories of tylostyles, oval mature selenasters, golf-ballshaped spherasters and two categories of spirasters (David-Colón et al. 2023). They differ only by the presence of acanthomicrorhabds with conical spines exclusively in the Brazilian specimens (Tabs. 1 and 3). Here, we consider the acanthomicrorhabds as variations of the spirasters II, since they have the same size and both are located in the outer cortex of the sponge. Thus, we amended the diagnosis of P. colombiensis to include acanthomicrohabds and expanded the distribution of this species from the Colombian Caribbean Sea to NE Brazil.
Placospongia caribica Rützler, Piantoni, van Soest & Díaz, 2014 and the Brazilian specimens of P. colombiensis share the orange color, two categories of tylostyles, oval to bean-shaped mature selenasters, spherasters, spirasters and acanthomicrorhabds with conical spines, but they clearly differ by the presence of oxyasters in P. caribica (Tab. 3).
description: Published as part of 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), pp. 495-525 in Zootaxa 5405 (4) on pages 498-506, DOI: 10.11646/zootaxa.5405.4.2, http://zenodo.org/record/10603692