Leucandrilla intermedia ( Row, 1909 )

Cavalcanti, Fernanda F., Chagas, Cléslei & Fonseca, Evelyn S. M., 2019, Taxonomic redescription of Leucandrilla wasinensis (Jenkin, 1908) and L. intermedia (Row, 1909) (Porifera, Calcarea): a first step to improve current knowledge on the typical features of the genus, Zootaxa 4568 (1) : -

Leucandrilla intermedia ( Row, 1909)

Leucilla intermedia: Row 1909: 205 , text-fig. 5, plate 19—fig. 7, plate 20—fig. 7

Leucandra infesta: Dendy & Row 1913: 771 ; Burton 1963: 265, text-fig. 128

Leucandrilla intermedia: Borojević et al. 2000: 227 ; Borojević et al. 2002: 1169; Cóndor-Luján et al. 2018: 42

Leucandrilla aff. intermedia: Van Soest & De Voogd 2018: 103 , figs. 62, 63

Material examined: Slides of the paralectotypes: BMNH 1954.2.24.5 (1 slide containing sections of the skeleton and 1 containing dissociated spicules), BMNH 1954.2.24.6 (only 1 slide with dissociated spicules), BMNH 1954.2.24.7 (2 slides), BMNH 1954.2.24.27 (1 slide), BMNH 1954.2.24.28 (1 slide), BMNH 1954.2.24.29 (1 slide), and BMNH 1954.2.24.30 (1 slide) (only sections of the skeleton). Suez, Red Sea.

Description: It is worth mentioning that the spicule categories observed in BMNH 1954.2.24.6 are typical of Amphoriscidae (by the presence, for instance, of giant tetractines) and very different from those found in the other samples, indicating that it is not Leucandrilla intermedia . In addition, it is not clear to us if the sections observed in the slide BMNH 1954.2.24.30 were prepared in a different manner (and thus, the organisation of the skeleton did not seem to be the same as that of the remaining specimens) or if it also corresponds to a different species. All the other specimens correspond to L. intermedia .

In the original description ( Row 1909) there is no mention to differences at the morphology of the specimens, which are described as “small, irregularly massive, and usually with a single osculum at the top”. The sections are not stained, but according to the original description, the aquiferous system is sylleibid. The sponge surface is perforated by giant diactines that cross the choanosome, almost reaching the atrium ( Fig. 3A ). Tangential triactines occur at the surface, being rare in the specimen BMNH 1954.2.24.28 ( Fig. 3B ). The cortical skeleton has also tetractines that are never giant; their short apical actine is projected into the sponge ( Fig. 3C ). Some subcortical lacunae and subcortical pseudosagittal triactines ( Figs. 3 B–C) were found in all the specimens but the BMNH 1954.2.24.27. Inner triactines are the main components of the choanosomal skeleton. The unpaired actines of those just below the cortical or subcortical layers point to the cortex, in opposition to the apical actines of cortical tetractines or (less common) to the long paired actine of the pseudosagittal spicules. Choanosomal tetractines ( Fig. 3D ) were found in two of the analysed specimens (BMNH 1954.2.24.7 and BMNH 1954.2.24.27). The skeleton of the choanosome is predominantly articulated, with several layers of spicules that point their unpaired actines to the distal portion of the sponge ( Fig. 3E ). Nevertheless, in some sections, the choanosome is disorganised, and it is not clear whether this disorganisation is caused by the presence of canals. The atrial skeleton is formed of tetractines that differ from those of the canals ( Fig. 3F ) mainly by the length of the apical actines ( Fig. 3H ). Microdiactines were found close to the cortex of the specimens BMNH 1954.2.24.27 and BMNH 1954.2.24.28 ( Fig. 3C ). Large triactines close to the atrial surface were observed in BMNH 1954.2.24.29 ( Fig. 3G ).

Spicules (measured from BMNH 1954.2.24.5, except for those indicated below):

Microdiactines ( Fig. 3C ): Thin and long, with blunt or sharp tips (93.5–116.4 ± 150.4–56.1/2.8 ± 0.5 µm; N = 4; BMNH 1954.2.24.28).

Diactines ( Fig. 4A ): Most of them are broken at the distal part. Straight and fusiform (549.3–991.4 ± 324.2– 1835.3/ 31.9 ± 6.9 µm; N = 30).

Cortical triactines ( Fig. 4B ): Actines are cylindrical, with blunt tips. Paired actines are commonly curved, and the angle formed by them is large (paired: 91.2–143.6 ± 32.0–208.3/9.8 ± 1.8 µm; unpaired: 93.9–146.6 ± 38.7– 225.0/15.8 ± 3.3 µm; N = 30).

Cortical tetractines ( Fig. 4C ): Actines are slightly conical with blunt tips. Basal actines are curved. Apical actine is smooth and straight (paired: 123.1–189.6 ± 21.4–226.7/15.1 ± 4.3 µm, N = 27; unpaired: 124.8–142.5 ± 11.2–155.5/19.6 ± 0.7 µm, N = 5; apical: 108.6–177.7 ± 29–201.7/17.3 ± 3.4 µm; N = 20).

Pseudosagittal triactines ( Fig. 4D ): Typical pseudosagittal, but the longest paired actine may be the length of the unpaired one (short paired: 178.1–200.9 ± 12.5–223.2/17.7 ± 2.5 µm, N = 20; long paired: 208.3–264.4 ± 19.3– 295.1/21.7 ± 2.2 µm, N = 17; unpaired: 160.9–199.0 ± 25.7–288.8/18.6 ±3.9 µm; N = 22).

Choanosomal triactines ( Fig. 4E ): They vary in shape and size. Most of them seem to have slightly conical actines, with blunt tips, equiradiate and with a large unpaired angle (paired: 236.0–305.5 ± 43.0–404.6/23.9 ± 4.1 µm; unpaired: 223.9–324.6 ± 49.8–400.2/29.2 ± 3.4 µm; N = 30).

Choanosomal tetractines ( Fig. 4F ): Similar to the choanosomal triactines, but with an apical actine that varies in size (paired: 168.1–239.8 ± 49.3–318.7/19.5 ± 3.7 µm; unpaired: 166.0–242.8 ± 62.3–339.0/21.3 ± 5.5 µm; apical: 48.3–74.6 ± 15.7–98.7/19.2 ± 3.9 µm; N = 10).

Tetractines of the canals ( Fig. 4G ): Cylindrical actines with sharp tips. Paired actines are long, and the apical actine is shorter than the unpaired one (paired: 55.2–66.7 ± 8.8–81.7/4.7 ± 0.6 µm; unpaired: 37.0–49.3 ± 12.1– 67.3/5.2 ± 1.3 µm; apical: 9.6–17.1 ± 7.5–37.1/5.7 ± 2.6 µm; N = 6, except for apical/N = 11).

Atrial tetractines ( Fig. 3H ): Similar to the tetractines of the canals, but with long apical actine (paired: 94.6– 159.6 ± 33.2–236.7/9 ± 2.8 µm, N = 25; unpaired: 81.9–121.6 ± 23.5–188.7/6.7 ± 2.7 µm, N = 24; apical: 172.0– 262.2 ± 50.0–343.4/11.7 ± 2.7 µm, N = 30; BMNH 1954.2.24.29).

Remarks: Microdiactines, pseudosagittal triactines and tetractines of the canals and choanosome were not mentioned in the original description of Leucandrilla intermedia ( Row 1909) . Another remarkable difference is the size of the apical actine of atrial tetractines. Although they have previously been described as extremely short (70– 80 x 7 285 µm; Row 1909), we found that they are considerably larger, as shown in Figures 3G and H (measurements by the present description: 172–343 x 11 µm). The difference observed between the paralectotypes analysed here and the specimen from the Gulf of Aqaba described by Van Soest & De Voogd (2018) is mainly the presence of atrial triactines in the latter. When compared to L. wasinensis , the skeletal composition of L. intermedia is similar: giant diactines and rare microdiactines, cortical tri- and tetractines, subcortical pseudosagittal triactines, choanosome formed of tri- and tetractines (although the latter were not found in all specimens of L. intermedia ) and atrial tetractines. On the other hand, differences between these species were mainly the type of aquiferous system (sylleibid in L. intermedia and leuconoid in L. wasinensis ), the shape and size of cortical triactines (see Description section of each species) and the presence of a layer of subatrial spicules only in L. wasinensis (in L. intermedia , only rare subatrial spicules were observed, and they occurred in only one specimen). Finally, it is important to emphasize that only paralectotypes were analysed in the present work, as the lectotype [possibly chosen by Burton (1963)] could not be located. Therefore, although the re-description of L. intermedia provided here is useful to a better understanding about the species, further studies aiming taxonomic decisions should consider that it is the lectotype, and not paralectotypes, that determines the identity of the species.

Figures

FIGURE 3. Skeletal organization of paralectotypes of Leucandrilla intermedia (A-C, H: BMNH 1954.2.24.28; D: BMNH 1954.2.24.7; E-G: BMNH 1954.2.24.29). A—Longitudinal section from the cortex (ct) to the atrium (at), B—Cortical triactine (left arrow) and pseudosagittal triactine (right arrow), C—Cortical tetractine and (arrow) microdiactines, D—Choanosomal tetractine (arrow), E—Articulated skeleton and canal (c) close to the atrium, F—Detail of the canal (c) surrounded by spicules, G—Large triactines close to the atrial cavity (at), H—Apical actines of atrial tetractines.

FIGURE 4. Spicules of the paralectotype of Leucandrilla intermedia BMNH 1954.2.24.5. A—Diactine, B—Cortical triactine, C—Cortical tetractine, D—Pseudosagittal triactine (sp: short paired; lp: long paired; u: unpaired), E—Choanosomal triactine, F—Choanosomal tetractine, G—Tetractine of the canals, H—Atrial tetractine.