Figure 1.
Paraleucilla magna in the Mar Piccolo di Taranto (central Mediterranean Sea).
A) epibiontic specimens on a farmed row of Mytilus galloprovincialis; B) view of a large specimen inhabiting an artificial pole, submerged for several years, together with numerous tubes of the polychaete Branchiomma luctuosum and the nudibranch Dendrodoris limbata.
Figure 2.
Box plots of the volume of Paraleucilla magna throughout the study period.
Each box displays the median, upper and lower quartiles of the distribution of sponge volume per month. Box whiskers represent the maximum and minimum value.
Figure 3.
Monthly trend in the volume of Paraleucilla magna specimens from the Mar Piccolo di Taranto over the study period.
Figure 4.
Ultrastructural details of oocytes of Paraleucilla magna.
A) primordial female germ cells located below the choanoderm gifted by short pseudopodial extensions (pe); B) young oocyte (o) crossing the choanoderm (ch); C) oocyte interposed between the choanoderm (ch) and the pinacocyte-like cells (p); D) oocyte in a chamber delimited by pinacocyte (p) and choanocyte layers (ch).
Figure 5.
Choanocyte chambers and details of transformed choanocyte chambers with putative male gametes of Paraleucilla magna.
A) choanocyte chambers (cc) arranged around the canals (c); B) choanocyte chamber lined by round-shaped choanocytes; C, D) transformed choanocyte chambers with precursor of male gametes (ccmg), oocyte (o); E) putative male gametes (pmg) directed toward the lumen of the chamber.
Figure 6.
Reproductive trend of Paraleucilla magna throughout the year: monthly frequency of specimens with reproductive elements in relation to sea-water temperature.
Figure 7.
Trend in the sexual cycle of Paraleucilla magna in the Mar Piccolo di Taranto.
Monthly mean value and standard error of size, number of reproductive elements per mm3 of sponge tissue (A = oocytes; B = transformed choanocyte chambers with putative male gametes; E = embryos; F = larvae) and % of sponge tissue occupied by reproductive elements (C = oocytes; D = transformed choanocyte chambers with putative male gametes; G = embryos; H = larvae).
Figure 8.
Main phases of the sexual reproductive cycle of Paraleucilla magna.
A) oocytes (o) and transformed chonaocyte chambers with putative male gametes (ccmg) coexisting in the same specimen; B, C, D) segmentation process; E) embryo at beginning of inversion process; F) amphiblastula larvae (scale bars: A, 50 µm; B–E, 25 µm; F, 100 µm).
Table 1.
The reproductive periods of Paraleucilla magna in the Atlantic Ocean and in the Mediterranean Sea.