Paraleucilla incomposita, Cavalcanti, Fernanda F., Menegola, Carla & Lanna, Emilio, 2014

Cavalcanti, Fernanda F., Menegola, Carla & Lanna, Emilio, 2014, Three new species of the genus Paraleucilla Dendy, 1892 (Porifera, Calcarea) from the coast of Bahia State, Northeastern Brazil, Zootaxa 3764 (5), pp. 537-554 : 547-550

Paraleucilla incomposita sp. nov.

Etymology. From Latin incomposita , meaning “disorganized”. This refers to the wide inner region below the inarticulated skeleton (outer region), where spicules are present without any apparent organization.

Diagnosis. Paraleucilla with a single apical osculum ornamented with a fringe of trichoxea. Several giant diactines protrude from its surface. The cortical skeleton is formed by a basal system of tetractines and by a few tangential triactines. Subatrial skeleton is composed of abundant tetractines and a small number of triactines. There are two categories of tetractines that can be easily distinguished from each other by the size of their apical actines. The inner region is wide. The atrial skeleton is composed of tetractines.

Type material. Holotype: UFBA POR 4246. [Martim Pescador Reef, Arraial d’Ajuda (16°29’S 39°03’W), Bahia, Brazil; 14/V/2012; depth: 3 meters; collected by Romário Guedes].

Type locality. Arraial d’Ajuda, Bahia, Brazil.

Description. Tubular sponge ( Figure 7 A) measuring 1.3 x 0.4 cm (osculum-basis axis and width, respectively). The surface is strongly hispid due to the presence of several diactines. Frequently, these spicules are broken close to the tip, but some of them have a sharp tip projecting through the sponge surface. The osculum is apical and ornamented with a short fringe of trichoxeas ( Figure 7 B). There are several layers of sagittal triactines at the base of the fringe. They are in part covered by the diactines from the sponge surface. The atrial cavity is large and hispid. The aquiferous system is leuconoid.

Giant diactines project through the sponge surface. These spicules penetrate the choanosome ( Figure 7 C). The cortical skeleton is composed of a basal system of tetractines and a few triactines arranged tangentially to the cortex. The choanoskeleton has trichoxea and is divided into an inarticulated (outer) region and a disorganized (inner) region ( Figures 7 D, E). The former is composed mainly by the apical actines of the cortical tetractines and by the unpaired actines of two categories of subatrial tetractines, as well as by a few subatrial triactines. These latter spicule categories are larger than the cortical spicules. The inner (disorganized) region is well developed. It has scattered spicules that are similar to the large subatrial tetractines and triactines mentioned above. The atrial skeleton is composed of small tetractines, which project their apical actines into the atrial cavity ( Figure 7 F).

Spicules: ( Table 3). Cortical triactines ( Figure 8 A): The actines range from cylindrical to slightly conical and blunt. The paired actines are commonly curved. Their size is variable. [Paired actines: 150 – 225.3 ± 49.0 – 300/ 22.2 ± 7.3 µm; unpaired actine: 130 – 233.3 ± 52.9 – 340/ 22.2 ± 6.8 µm (n= 1 specimen)]. Cortical tetractines ( Figure 8 B): Actines are slightly conical and sharp. In general, the basal actines are regular, and the paired actines are slightly curved. The apical actine is straight and variable in size. [Paired actines – 110 – 190.7 ± 46.2 – 340/ 17.5 ± 2.5 µm; unpaired actine – 130 – 217.7 ± 34.8 – 270/ 22.3 ± 3.1 µm; apical actine: 80 – 209.0 ±56.7 – 320/ 18.5 ±2.3 µm (n= 1 specimen)]. Subatrial tetractine I ( Figures 4 F-H; 8C): Actines are slightly conical and blunt. The basal actines are equiangular and equiradiated. The paired actines are straight or slightly curved. The apical actine is thick and shorter than the basal actines. [Paired actines: 210 – 271.7 ± 23.9 – 320/ 28.5 ± 4.6 µm; unpaired actine: 200 – 283.3 ± 36.6 – 370/ 30.0 ± 3.7 µm; apical actine: 140 – 162.5 ± 26.3 – 200/ 25.0 ± 4.1 µm (n= 1 specimen)]. Subatrial tetractine II ( Figure 8 D): Size is variable (see Figure 4 F-H), but all actines are slightly conical and blunt. The basal actines are regular or sagittal, and the unpaired actine is longer than the paired actines. The apical actine is thin and very short; it is sometimes vestigial. [Paired actines: 150 – 223.0 ± 36.2 – 320/ 19.0 ± 3.3 µm; unpaired actine: 170 – 255.3 ± 45.3 – 330/ 21.0 ± 4.4 µm; apical actine: [20 – 36.7 ± 10.3 – 60/ 11.7 ± 2.4 µm (n= 1 specimen)]. Subatrial triactines ( Figure 8 E): Regular. All actines are slightly conical with blunt tips. The paired actines are slightly curved. [Paired actines: 220 – 260.8 ± 19.7 – 290/ 24.2 ± 3.6 µm; unpaired actine: 210 – 281.7 ± 40.9 – 350/ 24.6 ± 4.0 µm (n= 1 specimen)]. Atrial tetractine ( Figure 8 F): All actines are cylindrical and sharp. The unpaired actine is often shorter than the paired actines, but spicules with a regular basal system can also be found. The apical actine is long and straight or slightly curved. [Paired actines: 130 – 211.7 ± 30.6 – 260/ 10.3 ± 1.3 µm; unpaired actine: 100 – 169.7 ± 28.3 – 220/ 11.2 ± 2.1 µm; apical actine: 40 – 119.0 ± 34.0 – 190/ 10.0 ± 0.0 µm (n= 1 specimen)]. Diactines ( Figure 8 G): Fusiform and slightly curved. The tips are sharp, but in some spicules the tip that is inserted in the sponge (the proximal tip) is thicker than the other tip (the distal one) and is blunt. [975 – 1431.2 ± 447.5 – 2300/ 34.4 ± 9.4 µm (n= 1 specimen)]. Trichoxea: Thin and long.

Spicule Actine Length (µm) Width (µm) N

Mean SD Mean SD

Cortical triactine paired 225.3 49.0 22.2 7.3 30 unpaired 233.3 52.9 22.2 6.8 30 Cortical tetractine paired 190.7 46.2 17.5 2.5 30 unpaired 217.7 34.8 22.3 3.1 30 apical 209.0 56.7 18.5 2.3 30 Subatrial tetractine I paired 271.7 23.9 28.5 4.6 30 unpaired 283.3 36.6 30.0 3.7 30 apical 162.5 26.3 25.0 4.1 0 4 Subatrial tetractine II paired 223.0 36.2 19.0 3.3 30 unpaired 255.3 45.3 21.0 4.4 30 apical 36.7 10.3 11.7 2.4 30 Subatrial triactine paired 260.8 19.7 24.2 3.6 12 unpaired 281.7 40.9 24.6 4.0 12 Atrial tetractine paired 211.7 30.6 10.3 1.3 30 unpaired 169.7 28.3 11.2 2.1 30 apical 119.0 34.0 10.0 0.0 30 Diactine -- 1431.2 447.5 34.4 9.4 12 Ecology. This specimen was found attached to a rodophyte macroalga.

Remarks. Paraleucilla incomposita sp. nov., like P. perlucida and P. princeps , has an atrial skeleton composed exclusively of tetractines. Paraleucilla perlucida can be easily differentiated from P. incomposita sp. nov. by its diactines, which are always organized into tufts, whereas in the diactines of P. incomposita sp. nov. are dispersed in the skeleton. In addition, the size of these diactines is also different between species [ P. perlucida : 175 – 303.6 ± 127.4 – 562.5/ 11.8 ± 1.2 µm; P. incomposita sp. nov: 975 – 1431.2 ± 447.5 – 2300/ 34.4 ± 9.4 µm]. Paraleucilla princeps and P. incomposita sp. nov. can be distinguished mainly by the compositions of their subatrial skeletons: P. princeps has one category of tetractines, while P. incomposita sp. nov. has two categories of tetractines and one category of triactines (the latter is not abundant; Figures 4 F-G; Figures 8 C-E). In addition, the size of the apical actine on each atrial tetractine is different [ P. princeps : 180 – 450/ 8 –12 µm; P. incomposita sp. nov.: 40 – 119.0 ± 34.0 – 190/ 10 ± 0.0 µm].

Of the new species described here, P. incomposita sp. nov. is the only one with abundant giant diactines (that are never organized in tufts) projecting through its surface. Moreover, it is the only species with tangential triactines on its surface, and with an atrial skeleton composed exclusively of tetractines. The choanoskeletal composition (number of spicule categories, and their size and shape; Figure 4 ; Tables 1-3) also differs between these three new species.

Figures

FIGURE 4. Histograms and box plots of the spicule measurements for the three new species: A— P. solangeae sp. nov.; B – E— P. o c a sp. nov. and F-H: P. incomposita sp. nov. A—Histograms showing the distributions of actine length for the subatrial triactines of the paratype of P. solangeae sp. nov. (UFBA POR 4242; top panel: paired actines, bottom panel: unpaired actines). B – C—Boxplots of the categories of subatrial triactines of P. oca sp. nov. (B—paired actines and C—unpaired actines). D – E— Boxplots of the categories of subatrial tetractines of P. o c a sp. nov. (D—paired actines and E—unpaired actines). F – H— Boxplots of the categories of subatrial triactines of P. incomposita sp. nov. (F—paired actines; G—unpaired actines and Hapical actines). Each box displays the median and upper and lower quartiles of the spicules measurements for each category. Box whiskers represent the maximum and minimum range. The p-value indicates a significant difference between spicule categories.

FIGURE 7. Paraleucilla incomposita sp. nov. (UFBA POR 4246, holotype). A—Preserved holotype; B—Fringe of trichoxea; C—Transverse section showing diactines in the skeleton (arrowheads) and the large inner region (ir) for comparison with the outer region (or); D—Detailed view of a transverse section showing the outer region (or) and the beginning of the inner region (below the outer region); E—Fragments of trichoxea in the choanosome; F—Tangential view of the tetractines in the atrial skeleton.

FIGURE 8. Spicules of Paraleucilla incomposita sp. nov. A—Cortical triactine; B—Cortical tetractine; C—Subatrial tetractine I; D—Subatrial tetractine II; E—Subatrial triactine; F—Atrial tetractine; G—Diactine.