Plakortis spinalis, Domingos, Celso, Moraes, Fernando & Muricy, Guilherme, 2013
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publication ID |
https://doi.org/ 10.11646/zootaxa.3718.6.2 |
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publication LSID |
lsid:zoobank.org:pub:20C2A3C6-EED3-41C3-86A5-391EE0868031 |
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DOI |
https://doi.org/10.5281/zenodo.6147334 |
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persistent identifier |
https://treatment.plazi.org/id/3D3C8786-AC0B-FFB7-FF75-9EFBFB76679E |
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treatment provided by |
Plazi |
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scientific name |
Plakortis spinalis |
| status |
sp. nov. |
Plakortis spinalis View in CoL sp. nov.
( Fig. 3 View FIGURE 3 )
Specimens examined (1). Holotype: MNRJ 8597, Sapata Cave, Fernando de Noronha Archipelago, Brazil, 15 m depth. Fernando Moraes coll., 10 August 2004.
Specimens examined for comparison. P. angulospiculatus : UFRJPOR 3900, 4791, Fernando de Noronha Archipelago, Brazil. UFRJPOR 4032, Tamandaré, Pernambuco State, Brazil. UFRJPOR 4116, 4118, Carrie Bow Key, Belize.
Plakortis hooperi QMG 312880. Papua New Guinea.
Plakortis insularis : UFRJPOR 3917, 4803; MNRJ 2126, 2138; all from Fernando de Noronha Archipelago, Brazil.
Plakortis microrhabdifera : MNRJ 2165, 2170, 2940, all from Atol das Rocas, Brazil.
Plakortis petrupaulensis sp. nov. MNRJ 11828, 11817, 11826, 11839; all from São Pedro e São Paulo Archipelago, Brazil.
Plakortis potiguarensis sp. nov.: UFPEPOR 585, Urca do Tubarão, Potiguar Basin, Rio Grande do Norte State, Brazil.
Diagnosis. Plakortis thinly encrusting, gray in color, cartilaginous in consistency, with a vaguely reticulated tangential ectosomal skeleton and a disorganized choanosomal skeleton with fiber-like structures; spicules are diods and triods, some of which spined, and tuberculate microrhabds; smooth siliceous spheres are also present.
Description. Shape thinly encrusting ( Fig. 3 View FIGURE 3 A), 4.0 by 1.5 cm wide by 0.5 cm thick. External and internal color gray in vivo, becoming light brown to cream after fixation in ethanol. Surface irregular, rugose, coriaceous. Oscules contracted, not visible in the preserved specimen. Consistency cartilaginous, slightly compressible.
Skeleton. Tangential ectosomal skeleton reticulate, with ill-defined multispicular spicule tracts forming circular meshes, 30-39-70 µm in diameter (n=20; Fig. 3 View FIGURE 3 B). In transverse sections, the ectosome is well differentiated and shows ascending spicule columns separated by ectosomal lacunae, 12–22-39 µm ( Fig. 3 View FIGURE 3 C, top). Subectosomal lacunae are absent. Choanosomal skeleton dense, disorganized, with a few denser, sinuous tracts parallel to the surface ( Fig. 3 View FIGURE 3 C, bottom). Some parts of the mesohyl show a golden color and look similar to illdefined spongin fibres ( Fig. 3 View FIGURE 3 D), but could not be easily separated form the mesohyl like common demosponge spongin fibers.
Spicules. Diods thin, slightly sinuous, with sharp endings and protuberant central torsion. Some diods have small spines along the actines or near the center ( Fig. 3 View FIGURE 3 E): 29-42.6-103 /1-2-4 µm (n = 20).
Triods smooth, Y-shaped, with sharp endings and center deformed like that of diods. Some triods also have small spines along the actines or near their intersection ( Fig. 3 View FIGURE 3 F): actines 24.7-37.5-49.4 / 1-3-5 µm (n=20). Microrhabds irregular, straight or curved, highly tuberculate ( Fig. 3 View FIGURE 3 G): 5-6.7-14 / 2-3-6 µm (n=20). Smooth siliceous spheres are common ( Fig. 3 View FIGURE 3 H): 1–20 µm (n=20).
Habitat and ecology. The only specimen was collected on a vertical wall inside a semi-obscure cave, 15 m depth. The sponge had no associated macrofauna.
Distribution. Endemic from Fernando de Noronha Archipelago, NE Brazil ( Fig. 1 View FIGURE 1 ).
Taxonomic remarks. Plakortis spinalis sp. nov. belongs to the group of Plakortis with microrhabds, which now also includes P. petrupaulensis sp. nov. as well as P. lita , P. microrhabdifera , P. hooperi and P. m y r a e. The new species is mostly similar to P. petrupaulensis sp. nov. by its thinly encrusting shape, disorganized choanosomal skeleton, and especially the tuberculate microrhabds; P. petrupaulensis sp. nov., however, differs by a smooth surface, light brown color, absence of triods, and absence of spined spicules. Plakortis spinalis sp. nov. differs from P. lita , P. microrhabdifera , P. myrae and P. hooperi by its gray color, presence of tubercles on microrhabds and presence of spines on diods and triods. It differs from all other species of Plakortis by the spined diods and triods, tuberculate microrhabds, and by the fiber-like structures in the choanosome ( Fig. 3 View FIGURE 3 D).
Etymology. The name spinalis refers to the presence of small spines on some diods and triods.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.