Placospongia amphinolastra, Sandes & Moraes & Muricy, 2024

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 : 514-516

publication ID

https://doi.org/ 10.11646/zootaxa.5405.4.2

publication LSID

lsid:zoobank.org:pub:3080C791-0BF8-45E0-940E-CDC796EAAEFD

DOI

https://doi.org/10.5281/zenodo.10619633

persistent identifier

https://treatment.plazi.org/id/998EB1A4-B682-45EC-9D00-9ED433024076

taxon LSID

lsid:zoobank.org:act:998EB1A4-B682-45EC-9D00-9ED433024076

treatment provided by

Plazi

scientific name

Placospongia amphinolastra
status

sp. nov.

Placospongia amphinolastra View in CoL sp. nov. Sandes, Moraes & Muricy

urn:lsid:zoobank.org:act:998EB1A4-B682-45EC-9D00-9ED433024076

( Figs. 4 View FIGURE 4 and 11–12 View FIGURE 11 View FIGURE 12 ; Tables 2 View TABLE 2 and 3 View TABLE 3 )

Synonyms

Placospongia sp. sensu Moraes 2011: 95.

Type material. Holotype: MNRJ 7878 View Materials , Ressurreta , Rata Island, Fernando de Noronha Archipelago, Pernambuco State, Brazil (3º48’46.764”S, 32º23’25.224”W), 8 m depth, coll. Eduardo Hajdu, 12 November 2003. GoogleMaps

Etymology. The specific epithet amphinolastra refers to the presence of immature selenasters similar to amphinolasters, typical of this species.

Diagnosis. Placospongia thinly encrusting, with light brown color and orange edges. The megascleres are tylostyles in two slightly overlapping categories. Microscleres are elongated, bean- or peanut-shaped mature selenasters, immature selenasters similar to amphinolasters, small spirasters with short and rugose rays, and rare spherasters.

Description ( Fig. 11a–b View FIGURE 11 ). Shape thinly encrusting, size 15 x 15 x 1 mm (length x width x thickness). The surface is smooth, composed by six cortical plates separated by grooves with circular openings 1–2 mm in diameter, probably oscules ( Fig. 11a View FIGURE 11 ). Color light brown with orange edges in vivo ( Fig. 11a View FIGURE 11 ), becoming beige in ethanol ( Fig. 11b View FIGURE 11 ). Consistency hard, but brittle.

Skeleton ( Fig. 11c–d View FIGURE 11 ). The cortex is 100–250 µm thick, distinct from the choanosome. The inner layer of the cortex is densely packed with selenasters and the outer layer is thin and sparse, formed by scarce spirasters. The choanosomal skeleton is composed of tylostyle tracts of 50–100 µm thick and 1000 µm apart, which run obliquely from substrate to the cortex ( Fig. 11c View FIGURE 11 ). Immature selenasters and rare spherasters are scattered throughout the choanosome, between the tylostyle tracts ( Fig. 11d View FIGURE 11 ).

Megascleres ( Fig. 12a–b View FIGURE 12 ). Tylostyles in two slightly overlapping categories, with blunt or mucronate ends; few modified to styles. The tyles are ovoid, round, lobate or bi-lobate ( Fig. 12a–b View FIGURE 12 ). Tylostyle I: 360–454–540 / 5–7–10 µm, tyle width 7–9–13 µm. Tylostyle II: 150–238–330 / 3–5–8 µm, tyle width 6–6–8 µm.

Microscleres ( Fig. 12c–g View FIGURE 12 ). Mature selenasters are elongate, bean- or peanut-shaped: total size 40–45–53 / 15– 21–30 µm, hilum with 7–8.5–9 µm in diameter. The spines are fused and form irregular, grooved or rugose plates ( Fig. 12c View FIGURE 12 ). Four types of immature selenasters are present: (I) straight, slender and spiny, with spines concentrated on the end of the shafts: 21–27–33 / 2–4.5–7 µm ( Fig. 12d View FIGURE 12 ); ( II) dumbbell-like shaped, with spined or lumpy shafts connecting two heads densely covered by sharp or bulbous spines, similar to amphinolasters: 29–33–36 / 13–15–19 / 9–11–13 µm (length x head width x shaft width) ( Fig. 12e View FIGURE 12 ); ( III) elongated, with short conical spines: 27–34–38 / 9–11–15 µm; ( IV) elongate to oval, with spines very closely set, but still recognizable in their individuality: 47–49– 51 / 15–20–23 µm. Spirasters small and thin, with short rugose spines, bent once or twice: 5–9–14 / 1–1–2 µm ( Fig. 12f View FIGURE 12 ). Spherasters rare, small, with short and conical rays: 11–12–13 µm in diameter (n=2) ( Fig. 12g View FIGURE 12 ).

Habitat. The species was collected at 8 m depth, in a crevice, associated with calcareous algae.

Geographical distribution ( Fig. 4 View FIGURE 4 ; Tab. 2 View TABLE 2 ). Only known from Fernando de Noronha Archipelago, Pernambuco State, Northeastern Brazil (present study).

Taxonomic remarks. Placospongia amphinolastra sp. nov. is defined by the combination of tylostyles, mature selenasters elongated, bean- or peanut-shaped, immature selenasters similar to amphinolasters, small spirasters with short and rugose rays, and rare spherasters.

The immature dumbbell-shaped selenasters of Placospongia amphinolastra sp. nov. are similar to amphinolasters, which are the main cortical microscleres of the genus Onotoa (de Laubenfels 1955; Rützler & Hooper 2000). Amphinolasters have lumpy shafts connecting two heads densely covered by bulbous spines ( Rützler & Hooper 2000). In the new species, it is unclear whether this is a distinct spicule type or an immature stage of development of the selenasters. In any case, we classified the new species in the genus Placospongia because it also has mature selenasters, the cortical microscleres that define the genus Placospongia and are absent in Onotoa .

Placospongia amphinolastra sp. nov. shares with the congeneric P. anthosigma ( Tanita & Hoshino, 1989) View in CoL from Japan and P. decorticans ( Hanitsch, 1895) View in CoL from the South European Atlantic Shelf the same accessory microscleres, viz., spirasters and spherasters. However, Placospongia anthosigma View in CoL is distinguished from Placospongia amphinolastra sp. nov. by its larger and rounded selenasters, larger and abundant spherasters and spirasters with larger and conical spines, while Placospongia decorticans View in CoL has oxyasters and selenasters larger than the new species ( Tab. 3 View TABLE 3 ).

Placospongia amphinolastra sp. nov. shares the presence of spherasters with P. caribica View in CoL , P. cristata View in CoL , P. colombiensis View in CoL , P. intermedia View in CoL and P. soesti View in CoL . Yet, it is easily distinguishable from all its congeners in the Tropical Western Atlantic: it is distinct from P. caribica View in CoL by the oxyasters and acanthomicrorhabds; from P. cristata View in CoL by the micro-spheroxyasters; from P. colombiensis View in CoL by the two categories of spirasters; from P. intermedia View in CoL by the presence of metasters and acanthomicrorhabds; and from P. soesti View in CoL by the presence of amphiasters and acanthomicrorhabs. Besides the absence of spherasters, P. ruetzleri View in CoL has spiny spirasters with long rays and acantomicrorhabds, and P. giseleae View in CoL has only acanthomicrorhabds as accessory microscleres ( Tab. 3 View TABLE 3 ). In addition, the immature selenasters similar to amphinolasters are exclusive of the new species.

Kingdom

Animalia

Phylum

Porifera

Class

Demospongiae

SubClass

Heteroscleromorpha

Order

Clionaida

Family

Placospongiidae

Genus

Placospongia

Loc

Placospongia amphinolastra

Sandes, Joana, Moraes, Fernando & Muricy, Guilherme 2024
2024
Loc

Placospongia sp.

Moraes, F. 2011: 95
2011
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