Paraleucilla oca, 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 : 544-547

Paraleucilla oca sp. nov.

Etymology. From Portuguese: oca , meaning “hollow”. This refers to the large atrial cavity of the holotype.

Diagnosis. Paraleucilla with tubular shape and apical osculum, ornamented by a fringe composed of trichoxeas, sagittal tetractines and diactines of variable size. Inside the sponge body, diactines are rare, small, and restricted to the cortex or an area just below the cortex. There are two categories of triactines and two categories of tetractines in the choanosomal skeleton. The atrial skeleton is formed mainly by tetractines; there are very few triactines.

Type material. Holotype: UFBA POR 4244 [Itaparica’s Marina, Itaparica Island, (12o53’21”S 38o41’03”W), Todos os Santos Bay, Bahia, Brazil; 27/I/2011; depth: 1 meter (on artificial substrate); collected by Laura Pioli Kremer, Cristiana Castello Branco and Júlio Cézar Fernandez].

Type locality. Itaparica Island, Itaparica, Bahia, Brazil.

Description. Tubular sponge ( Figure 5 A). The holotype measures 5.0 x 0.9 cm (osculum-basis axis and width, respectively). The color is white when alive and when preserved in ethanol. The surface is smooth, and there is a large apical osculum ornamented by a fringe of trichoxea ( Figure 5 B). Sagittal tetractines and fusiform diactines are also present around the oscular aperture ( Figure 5 C). The former have apical actines curved to the top of the fringe, and the latter are variable in size. The atrial cavity is wide and hispid. The aquiferous system is leuconoid.

The cortical skeleton is composed of the basal system of giant tetractines ( Figure 5 D). Small fusiform diactines were observed inserted in the sponge surface or just below the surface, but this was uncommon ( Figure 5 E). The inarticulated skeleton (outer region) is formed by the apical actine of the cortical tetractines and by the unpaired actine of the subatrial triactines and tetractines, which are also present in the inner region of the sponge. These subatrial triactines can be classified into two categories, based on their shape and size. Giant subatrial triactine I is an abundant type, and subatrial triactine II is an uncommon type. The subatrial tetractines were separated into two categories, also based on their shape and size. Giant subatrial tetractine I is the common type, and subatrial tetractine II is uncommon. The atrial skeleton is largely composed of tetractines with their apical actines pointing into the atrial cavity ( Figure 5 F). In addition, very rare atrial triactines were observed. Trichoxea were found close to the atrial region.

Spicules: ( Table 2). Diactines ( Figure 6 A): Fusiform, slightly curved, with sharp tips. The size is highly variable, and they are more abundant at the oscular fringe. [300 – 604.0 ± 187.5 – 900/ 20.0 ± 4.1 µm (n= 1 specimen)]. Cortical tetractine ( Figure 6 B): Giant and sagittal. Actines are conical and sharp. Either basal actines have the same length or the unpaired actine is slightly shorter than the paired ones. The apical actine is straight. [Paired actines: 350 – 503.0 ±72.4 – 650/ 58.2 ± 6.5 µm; unpaired actine: 210 – 481.7 ±110.8 – 680/ 55.8 ±6.2 µm; apical actine: 400 – 638.7 ± 123.1 – 810/ 56.2 ± 7.1 µm (n= 1 specimen)]. Subatrial tetractine I ( Figures 4 D, E; 6C): Similar to the previous category, but with a different apical actine. Basal actines have the same length, or the unpaired actine is slightly shorter than the paired ones. The apical actine is curved, shorter and thinner than the basal ones. [Paired actines: 290 – 521.3 ±115.2 – 730/ 56.0 ±10.2 µm; unpaired actine: 380 – 592.7 ± 95.7 – 780/ 57.8 ± 9.8 µm; apical actine: 100 – 173.6 ± 35.6 – 220/ 45.4 ±6.1 µm (n= 1 specimen)]. Subatrial tetractine II ( Figures 4 D, E; 6D): All actines are slightly conical, with sharp tips. In the basal system, paired actines are in general curved and shorter than the unpaired actine. The apical actine is thin, short, and curved. [Paired actines: 180 – 289.5 ± 56.6 – 380/ 30.5 ± 6.0 µm; unpaired actine: 200 – 326.0 ±94.9 – 510/ 32.5 ±6.0 µm; apical actine: it was not possible to measure these actines due to the positioning of the spicules on the microscope slides (n= 1 specimen)]. Subatrial triactine I ( Figure 6 E): Giant and slightly sagittal. Actines are conical and sharp. In general, the paired actines are curved and have the same size, or they are shorter than the unpaired actine; however, some spicules have all actines that are all different sizes. [Paired actines: 320 – 490.7 ±86.2 – 710/ 48.5 ± 9.7 µm; unpaired actine: 380 – 577.3 ± 85.3 – 710/ 49.8 ± 9.7 µm (n= 1 specimen)]. Subatrial triactine II ( Figure 6 F): Sagittal and variable in size ( Figure 4 B,C). Actines range from cylindrical to slightly conical, with sharp tips. In general, the paired actines are curved and shorter than the unpaired actine, but sometimes the actines are straight or equiradiated. [Paired actines: 110 – 238.3 ±58.9 – 370/ 16.1 ± 5.2 µm; unpaired actine: 200 – 364.0 ± 89.1 – 550/ 17.5 ± 6.5 µm (n= 1 specimen)]. Atrial tetractine ( Figure 6 G): All actines are cylindrical with sharp tips. Actines of the basal system are sometimes uniform. Sometimes, however the size of the unpaired actine varies, and the unpaired actine may be larger than the others. The apical actine is short, smooth and curved. [Paired actines: 210 – 318.7 ± 39.1 – 390/ 11.5 ± 2.3 µm; unpaired actine: 130 – 261.3 ± 78.6 – 420/ 11.8 ±2.4 µm; apical actine: 70 – 109.2 ±18.1 – 140/ 10.5 ±1.5 µm (n= 1 specimen)]. Trichoxea: Straight and very thin.

Spicule Actine Length (µm) Width (µm) N

Mean SD Mean SD

Diactines -- 604.0 187.5 20.0 4.1 10 Cortical tetractines paired 503.0 72.4 58.2 6.5 30 unpaired 481.7 110.8 55.8 6.2 30 apical 638.7 123.1 56.2 7.1 30 Subatrial tetractines I paired 521.3 115.2 56.0 10.2 30 unpaired 592.7 95.7 57.8 9.8 30 apical 173.6 35.6 45.4 6.1 11 Subatrial tetractines II paired 289.5 56.6 30.5 6.0 20 unpaired 326.0 94.9 32.5 6.0 20 Subatrial triactines I paired 490.7 86.2 48.5 9.7 30 unpaired 577.3 85.3 49.8 9.7 30 Subatrial triactines II paired 238.3 58.9 16.1 5.2 47 unpaired 364.0 89.1 17.5 6.5 47 Atrial tetractines paired 318.7 39.1 11.5 2.3 30 unpaired 261.3 78.6 11.8 2.4 30 apical 109.2 18.1 10.5 1.5 30 Ecology. The specimen was collected on panels (artificial substrate) that had been used for experiments on larval recruitment of marine invertebrates. These panels remained submerged for three months. Therefore, three months is the maximum age of the specimen, which seems to have a high growth rate; it is quite large (a single tube measuring 5.0 x 0.9 cm).

Remarks. In addition to Paraleucilla oca sp. nov., seven other species of the genus Paraleucilla have diactines in their skeletons: P. cucumis ( Haeckel, 1872) , P. perlucida , P. princeps ( Row & Hôzawa, 1931) , P. saccharata ( Haeckel, 1872) , P. sphaerica , P. solangeae sp. nov., and P. incomposita sp. nov. Nevertheless, with the exception of P. sphaerica and P. solangeae sp. nov., all the other five species have a tangential layer of triactines in their cortical skeletons, which is absent in P. o c a sp. nov. The species Paraleucilla sphaerica can be distinguished from P. oca sp. nov. mainly by the following: the size of its diactines [94 – 177.5 ± 5.8 –315/ 9.0 ±1.2 µm in P. sphaerica ; 300 – 604.0 ± 187.5 – 900/ 20.0 ±4.1 µm in P. oca sp. nov.], the abundance of triactines in its atrial skeleton, and by the categories of subatrial triactines and tetractines that are present. There is one type of triactine/ tetractine in the subatrial skeleton of P. sphaerica , but in P. o c a sp. nov. there are two types of subatrial triactine and two types of subatrial tetractine (see Figures 4 B–E; Figures 6 C–F). The presence of four categories of subatrial spicules also distinguishes P. o c a sp. nov. from P. solangeae sp. nov. Moreover, the latter has abundant atrial triactines and tufts of diactines in its skeleton, which do not occur in P. oca sp. nov.

Paraleucilla oca sp. nov. is defined here based on the analysis of a sole specimen (holotype UFBA POR 4244). This species has a skeletal composition that distinguishes it as a species that is new to science. However, we believe that analysis of additional specimens could be necessary to support the spicule measurements presented here, especially for the subatrial triactine categories.

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 5. Paraleucilla oca sp. nov.. A—Preserved holotype (UFBA POR 4244); B—Oscular fringe; C—Detailed view of the base of the oscular fringe, showing sagittal spicules (arrow heads); D—Transverse section showing the outer region (or) and inner region (ir); E—Diactine inserted into the sponge body, just below the cortical skeleton (arrow head); F—Tangential view of the atrial skeleton.

FIGURE 6. Spicules of Paraleucilla oca sp. nov. A—Diactine; B—Cortical tetractine; C—Subatrial tetractine I; D—Subatrial tetractine II; E—Subatrial triactine I; F—Subatrial triactine II; G—Atrial tetractine.