Leucascus roseus Lanna, Rossi, Cavalcanti, Hajdu & Klautau, 2007

Cavalcanti, Fernanda F., Rapp, Hans Tore & Klautau, Michelle, 2013, Taxonomic revision of Leucascus Dendy, 1892 (Porifera: Calcarea) with revalidation of Ascoleucetta Dendy & Frederick, 1924 and description of three new species, Zootaxa 3619 (3), pp. 275-314 : 293-294

Leucascus roseus Lanna, Rossi, Cavalcanti, Hajdu & Klautau, 2007

Diagnosis: Colour in vivo is pink. Cortical and choanosomal skeletons formed mainly by triactines. Atrial skeleton formed mainly by tetractines.

Synonymies: Leucascus roseus : Lanna et al. 2007: 1558; Muricy et al. 2008: 129; Lanna et al. 2009.

Type material: MNRJ 5827 (Holotype; Alcatrazes Archipelago, São Sebastião, SP; coll. E. Hajdu & M. Custódio; 02/V/2002; depth: 14 m)

Type locality: Alcatrazes Archipelago, São Sebastião, São Paulo, Brazil.

Additional analysed material: UFPEPOR 571 (Urca do Tubarão, Guamar, Potiguar Basin, RN; coll. G. Muricy; 03/III/2007; depth: 8 m; colour in vivo: pink); UFPEPOR 614 (Cabeço do Oliveira, Guamar, Potiguar Basin, RN; coll. L. Monteiro; 02/III/2007; depth: 12 m; colour in vivo: pink); UFRJPOR 4719 (Ilha Redonda, Abrolhos Archipelago, BA; coll. G. Muricy; 28/X/1997; depth: 1 m; colour in vivo: pink); UFRJPOR 5104 (Forno Beach, Arraial do Cabo, Rio de Janeiro, RJ; 03/I/1996; colour in vivo: pink).

Description: The colour in vivo is pink, but the preserved specimens are always white ( Figures 10 A, B). The holotype is very fragile and delicate with soft consistency. This specimen was damaged during the sampling when it was scraped off the substrate. It measures 1.5 x 1.7 x 1.0 cm. The body is lobate and covered by a delicate cortical membrane ( Figure 10 B). In some points it is possible to observe the tightly anastomosed tubes below this membrane. The oscula are numerous and localized on the top of short elevations. Some of them are surrounded by a thin membrane, but others lack this membrane.

The cortical skeleton is composed mainly of triactines, but tetractines are also present ( Figure 10 C). The abundance of the tetractines in the cortical skeleton is very variable, going from few to rare. In the tubes, both categories are present, but the triactines are again more abundant ( Figure 10 D). Consequently, the tubes are smooth, with rare apical actines of tetractines ( Figure 10 E). In the atrial skeleton, the most abundant spicules are tetractines, and only rare triactines are present ( Figure 10 F).

Spicules ( Table 7):

(i) Triactines ( Figure 11 A): The shape of these spicules is variable, but they are in general regular. Actines are cylindrical, straight, with blunt tips;

(ii) Tetractines ( Figure 11 A): Regular. Actines are cylindrical, straight, with blunt tips. The apical actine is long and ornamented with spines ( Figure 11 B).

Remarks: Leucascus roseus was first recorded from São Sebastião (Southeast Brazil) and was recently found in the Potiguar Basin, (Northeast Brazil) (Muricy et al. 2008; Lanna et al. 2009). The analysis of specimens deposited in the UFRJPOR collection revealed that this species had already been found and collected in Arraial do Cabo (Rio de Janeiro, Southeast Brazil) and in the Abrolhos Archipelago (Northeast Brazil).

In the original description of this species the variation in the length of the actines of the triactines was not mentioned. The triactines are usually regular, but one or even all actines may have different lengths. Another important character not mentioned in the original description is the presence of spines in the apical actine of the tetractines.

Distribution: South-West Atlantic Ocean. Up to date, the species has only been recorded from the Brazilian coast: São Sebastião—São Paulo State (Lanna et al. 2007), Potiguar Basin—Rio Grande do Norte State (Muricy et al. 2008; Lanna et al. 2009), Abrolhos Archipelago—Bahia State, and Arraial do Cabo—Rio de Janeiro State. Spalding et al. (2007) corresponding ecoregions: Northeastern Brazil, Eastern Brazil, and Southeastern Brazil.

Spicules/ Specimens Actine Length (µm) Width (µm) N

Min Mean SD Max Min Mean SD Max

Triactine

MNRJ 5827 (H) 72.0 98.7 10.7 114.0 6.0 9.3 1.5 15.0 30

UFPEPOR 571 88.4 105.9 7.5 122.0 10.4 11.8 1.0 14.3 30

UFPEPOR 614 98.8 112.4 6.1 125.0 10.4 11.8 0.9 14.3 30

UFRJPOR 4719 83.2 96.0 8.6 117.0 9.1 10.6 0.9 13.0 30

UFRJPOR 5104 78.0 96.8 7.3 114.0 9.1 10.4 0.6 11.7 30

All specimens 72.0 102.0 6.3 125.0 6.0 10.8 0.9 15.0 –

Tetractine Basal

MNRJ 5827 (H) 75.0 91.0 7.2 105.0 6.0 8.9 0.7 10.5 30

UFPEPOR 571 83.2 106.9 8.9 125.0 10.4 12.2 0.9 14.3 30

UFPEPOR 614 88.4 104.7 6.0 114.0 10.4 11.6 1.0 13.0 30

UFRJPOR 4719 75.4 88.2 6.6 101.0 9.1 10.3 0.6 11.7 30

UFRJPOR 5104 83.2 94.0 5.3 109.0 9.1 10.2 0.7 11.7 30

All specimens 75.0 97.0 7.5 125.0 6.0 10.6 1.1 14.3 –

Apical

MNRJ 5827 (H) 45.0 55.9 13.1 96.0 3.0 4.4 0.8 6.0 30

UFPEPOR 571 44.2 55.7 8.6 78.0 3.9 5.2 0.8 7.8 30

UFPEPOR 614 33.8 55.2 8.0 67.6 3.9 5.1 0.4 5.2 30

UFRJPOR 4719 33.8 54.2 15.5 93.6 3.9 4.8 0.7 6.5 30

UFRJPOR 5104 31.2 46.0 8.2 67.6 3.9 4.8 1.0 7.8 30

All specimens 31.2 53.4 3.7 96.0 3.0 4.9 0.3 7.8 –

Figures

FIGURE 10. Leucascus roseus. A, Specimen alive (photo. E. Hajdu); B – F, MNRJ 5827, holotype. B, Preserved specimen; C, Cortical membrane; D, Spicules in the wall of a choanocyte tube; E, Apical actine of a tetractine projected into the lumen of a tube (arrow); F, Atrial membrane.

FIGURE 11. Leucascus roseus (MNRJ 5827, holotype). A, Triactine (left) and tetractine (right); B, Apical actine with spines (SEM).