Fig. 4 in Rare freshwater sponges of Australasia: new record of Umborotula bogorensis (Porifera: Spongillida: Spongillidae) from the Sakaerat Biosphere Reserve in Northeast Thailand

Fig. 4. Umborotula bogorensis (Weber, 1890) from the Sakaerat Biosphere Reserve, NE Thailand. SEM micrographs. a. Gemmules in a group within skeletal meshes. Gemmular theca with almost flat foraminal area. Several free gemmuloscleres also scattered in the skeletal network. b. Gemmule (basal area, top view) with developed outer layer covering the distal rotules of radial gemmuloscleres. c–d. Gemmules showing foraminal area (central); outer layer is lacking (top view). e. Gemmule without outer layer showing partially dissociated gemmuloscleres in the pneumatic layer and the smooth inner layer of compact spongin. Foramen simple, with short collar. f. Gemmule (cross section) with foraminal tubule and radial gemmuloscleres in the trilayered theca. g. Outer layer at the theca surface with distal rotules of gemmuloscleres. h. Distal rotules of gemmuloscleres without outer layer. i. Proximal rotules of gemmuloscleres adhering to the inner layer of the theca. j–k. Foraminal area supported by a network of spongin fibres and a rosette of radial gemmuloscleres. l. Architecture of trilayered gemmular theca with radial gemmuloscleres and spiny shafts (cross section). m–o. Fibrous network of thin spongin fibres in the pneumatic layer (detail, cross section).