FIGURE 10 in Adaptive morpho-traits, taxonomy and biogeography of Metania Gray, 1867 (Porifera: Spongillina: Metaniidae) with the description of a new species from Madagascar

FIGURE 10. Schema of relevant morpho-traits divergences of gemmular theca architecture at the genus level in the family Metaniidae. Spatial arrangement of gemmuloscleres (left) and layers of the theca (right): 1) outer layer; 2) pneumatic layer; 3) inner layer. In Corvomeyenia the pneumatic layer is shifted from its usual position i.e. not in contact with the inner layer and overlapping the distal tips of the radially arranged birotules. In Metania and Acalle sharing the same trilayered gemmular architecture the pneumatic layer fill the entire space between radial gemmuloscleres (boletiform in Acalle vs. tubelliform in Metania); moreover the Acalle gemmules are ornate by supplementary pseudobirotules in the outer layer. In Houssayella and Drulia the pneumatic layer is lost. The gemmuloscleres of Houssayella (Trochospongilla-like birotules) are radially embedded in the two resting theca layers. The single-rotule gemmuloscleres (parmuliform) of Drulia are laid directly on the gemmular surface or pluristratified and embedded in the two resting layers of the theca. Not to scale.