Ascoleucetta ventricosa (Carter, 1886)

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 : 303-307

Ascoleucetta ventricosa (Carter, 1886)

Diagnosis: Cortex with conspicuous inhalant apertures. Microdiactines projected into the lumen of these apertures.

Synonymies: Clathrina ventricosa : Carter 1886: 512; Leucosolenia ventricosa: Dendy 1891: 60 ; Ascandra ventricosa: Breitfuss 1898: 215 ; Leucosolenia ventricosa: Dendy & Row 1913: 724 ; Dendy 1918: 7; Tanita 1943b: 82; Burton 1963: 230; Ascaltis ventricosa: Borojevic 1968: 205 ; Leucascus ventricosus: Klautau & Valentine 2003: 3 .

Type material: BMNH 1886.12.15.32 (= BMNH 1886.12.16.32; lectotype; Port Phillip Heads, Australia; Bracebridge Wilson collection).

Type locality: Port Phillip Heads, Australia.

Additional analysed material: BMNH 1887.7.12.7 ii (Port Phillip Heads, Australia, Bracebridge Wilson collection), and SAM S887 (Great Australian Bight Marine Park, Benthic Protection Zone; 3224’65’’S, 13039’40’’E; 21/IV/2002; depth: 59 m). WAM Z40366, Western Australia, Dongara, Irwin Reef. Station JWAM30/ T3, 2918.23’S, 11451.81E, 7.4 m. Coll. J Fromont, CS Whisson and GI Moore 15.03.2006. ZIL (Port Phillip Heads, Australia, Breitfuss Collection NO 43, 1 specimen).

Description: According to the original description, the colour in vivo is white or pinkish brown, the last occurring probably due to the proximity with a red sponge (Carter 1886). After fixation, the sponges are beige or white ( Figures 19 A, B). The body has a firm consistency and is surrounded by a continuous cortex with several conspicuous inhalant apertures. The anastomosis of the tubes varies according to the region of the sponge, being tight externally and loose internally, although this is not so evident in the specimen WAM Z40366 possibly because of its fixation ( Figure 19 C). It was not possible to recognize oscula in the fragment of the holotype. The atrium is wide and surrounded by a thin membrane. Reproductive elements are present in the holotype.

The cortical skeleton is formed by large triactines, which are exclusive of this region, and small triactines ( Figure 19 D). In the fragment of the holotype it was not possible to observe these small triactines, but they were present in all the other analysed specimens. Surrounding each inhalant aperture there were fringes of microdiactines, organized in tufts, and pointing into the lumen ( Figures 19 E, F). The skeleton of the choanocyte tubes was composed of small triactines and tetractines. Some of these tetractines project their apical actine into the lumen of the tubes, which become hispid ( Figure 20 A), but smooth tubes are also present. The atrial skeleton is formed by triactines and tetractines similar to those found in the choanocyte tubes, however, tetractines seem to be more abundant here ( Figure 20 B).

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

Min Mean SD Max Min Mean SD Max N

Microdiactine

BMNH 1886.12.15.32 (L) – – – – – – – – 0

BMNH 1887.7.12.7 ii 46.2 100.0 28.0 133.6 2.4 3.9 0.7 4.9 13

S887 75.3 117.2 26.7 162.8 2.4 3.4 0.7 4.9 20

All specimens 46.2 108.6 8.6 162.8 2.4 3.6 0.2 4.9 – Cortical triactine

BMNH 1886.12.15.32 (L) 136.5 208.9 61.2 388.5 35.1 52.6 13.3 84.0 30

BMNH 1887.7.12.7 ii 170.0 243.7 40.2 310.0 25.0 39.0 7.5 55.0 30

S887 170.0 371.3 65.3 470.0 35.0 69.5 11.4 90.0 30

All specimens 136.5 274.6 69.8 388.5 25.0 53.7 12.5 90.0 – Choanosomal triactine

BMNH 1886.12.15.32 (L) 117.0 146.4 11.8 169.0 15.6 19.3 2.0 23.4 30

BMNH 1887.7.12.7 ii 110.0 140.8 16.7 180.0 10.0 15.8 2.1 20.0 30

S887 100.0 126.2 16.5 160.0 12.5 14.5 1.8 17.5 30

All specimens 100.0 137.8 8.5 180.0 10.0 16.5 2.0 23.4 – Tetractine Basal

BMNH 1886.12.15.32 (L) 70.2 131.3 16.6 156.0 15.6 19.1 1.6 20.8 30

BMNH 1887.7.12.7 ii 100.0 133.5 15.9 165.0 10.0 15.0 1.9 20.0 30

S887 105.0 129.2 11.0 150.0 10.0 13.6 1.7 15.0 30

All specimens 70.2 131.3 1.8 165.0 10.0 15.9 2.3 20.8 –

Apical

BMNH 1886.12.15.32 (L) 44.2 72.5 25.3 130.0 6.5 8.9 1.3 11.7 22

BMNH 1887.7.12.7 ii 34.0 56.0 10.4 77.8 3.6 5.1 0.8 7.3 30

S887 34.0 66.5 18.6 111.8 2.4 3.4 0.7 4.9 30

All specimens 34.0 65.0 6.8 130.0 2.4 5.8 2.3 11.7 – Spicules ( Table 11):

(i) Microdiactines: Small, with sharp tips;

(ii) Cortical triactines ( Figure 20 C): Large. Actines are conical, straight or slightly curved, sometimes becoming similar to tripods, and with blunt tips;

(iii) Triactines ( Figure 20 D): Regular, with conical actines and blunt tips;

(iv) Tetractines ( Figure 20 E): Similar to the triactines. The apical actine is smooth ( Figure 20 F).

Remarks: There is a problem with the label of the type specimen of Ascoleucetta ventricosa deposited in the NHM. Both specimens BMNH 1886.12.15.32 and BMNH 1886.12.16.32 are labelled as “ holotype - Clathrina ventricosa ”. Nevertheless, the analysis of these specimens revealed that they are two fragments of the same specimen. Moreover, the specimen should be considered a lectotype, as Carter (1886) did not designate a holotype.

Carter (1886) described this species as Clathrina ventricosa , but some years later Dendy (1891) transferred it to Leucosolenia , and more recently Klautau and Valentine (2003) reallocated it in Leucascus . As we are proposing the revalidation of Ascoleucetta , this species has to change genus again, becoming Ascoleucetta as it has all morphological characteristics of this genus.

Analysing this species, Dendy (1891) described important characters that were not present in the original description. One of them was the “ type D canal system”, which is presently called solenoid, the other was the presence of microdiactines (which he erroneously called trichoxea), in the margin of the inhalant apertures. These spicules were also mentioned by Burton (1963) and were observed in all specimens analysed here.

Ascoleucetta compressa is very similar to A. ventricosa . However, these species can be easily differentiated by the presence of trichoxeas in the inhalant apertures of A. compressa and microdiactines in A. ventricosa .

Distribution: South-West Pacific Ocean. The species was found next to Port Phillip Heads (Carter 1886; Dendy 1891), Tasmania (Dendy 1918), and in the Great Australian Marine Park (as Leucascus sp.; Sorokin, Currie & Ward 2005)— Australia. Spalding et al. (2007) corresponding ecoregions: Bassian and Great Australian Bight.

Figures

FIGURE 19. Ascoleucetta ventricosa. A – B, Preserved specimen (BMNH 1887.7.12.7 (ii) (modified from Cavalcanti & Klautau 2011; Copyright permission 11035892); C, WAM Z 40336; D – F, SAM S 887. C, Transverse section showing the cortex (ct), choanocyte tubes and atrium (at); D, Cortical skeleton (SEM); E, Microdiactines (arrow) protruding into the lumen of an inhalant aperture (SEM); F, Microdiactines (SEM).

FIGURE 20. Ascoleucetta ventricosa (BMNH 1886.12. 15.32, lectotype); A, Apical actine of a tetractine projected into the lumen of a choanocyte tube (arrow); B, Atrial membrane; C, Cortical triactine; D, Choanosomal triactine; E, Tetractine; F, Apical actine of a tetractine (SEM).