Leucascus protogenes (Haeckel, 1872) Haeckel, 1872

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 : 290-292

Leucascus protogenes (Haeckel, 1872) comb. nov.

Diagnosis: Cortical membrane with conspicuous inhalant apertures irregularly distributed on the surface. Only triactines are present.

Synonymies: Ascetta primordialis var. protogenes: Haeckel 1872: 17 ; Ascetta procumbens : von Lendenfeld 1885: 1086; Clathrina primordialis: Carter 1886: 510 ; Leucosolenia protogenes: Dendy 1891: 58 ; Breitfuss 1897: 213; Dendy & Row 1913: 726; Dendy & Frederick 1924: 480; Brøndsted 1926 (?): 297; Breitfuss 1932: 243; Breitfuss 1935 (?): 13; Tanita 1943a (?): 371; Tanita 1943b: 24, 74; Burton 1963: 225.

Type material: Unknown

Type locality: near Port Phillip Heads ( Australia)— sensu Dendy 1891

Analysed material: BMNH 1925.11.1.29 ( Australia; Dendy collection). This specimen is been suggested as a neotype.

Description: The colour alive is unknown but after fixation it is beige ( Figure 9 A). The cormus is formed by thin and tightly anastomosed tubes, although some larger tubes are also present. The entire cormus is surrounded by an external membrane and another membrane covers the atrium. Several crustaceans are present inside the studied specimen.

The skeleton consists of two categories of triactines. The cortical skeleton is formed by triactines with thicker actines ( Figure 9 B), while the skeleton of the choanocyte tubes is formed by triactines with thinner actines ( Figure 9 C). As there are only triactines, the lumen of the tubes is smooth. The atrial skeleton is composed of triactines similar to those of the choanocyte tubes.

Spicules ( Table 6 ):

(i) Cortical triactines ( Figure 9 D): Regular. Actines are conical, straight, with blunt tips; (ii) Triactines of the tubes and of the atrial skeleton ( Figure 9 D): Regular. They are similar to the cortical triactines, but their actines are thinner.

Remarks: The original description of Ascetta primordialis and its four varieties is very incomplete. The variety protogenes , for example, was distinguished from the others only by the presence of triactines of one size forming a monolayer on the surface, while the others showed more than one layer or more than one size category of triactines. Moreover, Haeckel (1872) did not designate any type material and did not make any correlation between the varieties and the analysed specimens, which are probably lost (Burton 1963). He also did not mention any special distribution for A. protogenes , just making the comment that this variety was of a common form. For Ascetta primordialis as a whole he cited the following distribution: Mediterranean Sea, Adriatic Sea, Red Sea, Atlantic Ocean, Indian Ocean, and Pacific Ocean.

After Haeckel (1872), Ascetta primordialis var. protogenes was mentioned again only by Dendy (1891) when he was describing specimens from near Port Phillip Heads ( Australia). Dendy (1891) elevated protogenes to the species rank, transferred it to the genus Leucosolenia and redefined it, as Haeckel had included specimens with different types of aquiferous system organization in this variety. Since then, Leucosolenia protogenes (Haeckel, 1872) has been considered sensu Dendy (1891).

In the same work, Dendy synonymized L. protogenes with Ascetta procumbens Lendenfeld, 1885 , mentioning that the type specimen he analysed of A. procumbens represented L. protogenes . The type specimens of A. procumbens were later analysed by Klautau and Valentine (2003) that revalidated A. procumbens as Clathrina procumbens . Klautau and Valentine (2003) mentioned that one of the type specimens examined by Lendenfeld (and probably by Dendy; BMNH 1886.6.7.3) was indeed not C. procumbens , but Leucosolenia (Ascaltis) protogenes .

After analysing more and better preserved specimens, we concluded that this species is in fact Leucascus protogenes and we propose the specimen BMNH 1925.11.1.29 to be the neotype of this species. Up to date, L. protogenes is the only species of the genus with only triactines.

Distribution: Indian and Pacific Oceans: Near Port Phillip Heads, Abrolhos Islands, and Port Jackson—Australia (von Lendenfeld 1885; Carter 1886; Dendy 1891; Dendy & Frederick 1924); Moko Hinau Island and Island Bay—New Zealand (Brøndsted 1926). The occurrence of this species in Japan (Tanita 1943a, b) could not be confirmed as these descriptions of L. protogenes are very incomplete. Spalding et al. (2007) corresponding ecoregions: Bassian, Houtman, Manning-Kawkesbury, Northeastern New Zealand, and Central New Zealand.

Figures

FIGURE 9. Leucascus protogenes (BMNH 1925.11. 1.29, neotype). A, Fragment of the preserved specimen; B, Cortical membrane; C, Triactines in the wall of a choanocyte tube; D, Cortical (left) and choanosomal (right) triactines.

Tables

TABLE 6. Spicules measurements (µm) of the proposed neotype of Leucascus protogenes (BMNH 1925.11.1.29).

Spicules		Length (µm)			Width (µm)
	Min	Mean SD	Max	Min	Mean SD	Max	N
Cortical triactine	96.0	144.2 19.4	177.0	18.0	19.7 1.5	21.0	30
Choanosomal triactine	84.0	123.7 14.8	144.0	13.5	14.3 0.7	15.0	30