FIGURE 12A–F in Description of new chiactine-bearing sponges provides insights into the higher classification of Calcaronea (Porifera: Calcarea)

FIGURE 12A–F: Megapogon schiaparellii sp. nov. A: preserved holotype MNA-02762. B: histological section including cortical layer, choanosome and atrial cavity. C: SEM image of cortical layer. D: histological section including cortical layer, choanosome and atrial cavity. E: histological section showing choanocyte chambers. F: SEM image of microdiactine. Abbreviations: At = atrial cavity; Chc = choanocyte chambers; Cor = cortical layer/cortex; Ctr = cortical triactines; Di = diactines; Mic = microdiactines; Tric = trichoxeas.