Figure 1.
Dendrophyllia boschmai and Dendrophyllia cribrosa.
A–D, Dendrophyllia boschmai (OCU 6652–6661). E–H, Dendrophyllia cribrosa (OCU 6662–6671). A, E, Side views of whole colonies. Scale bars = 50 mm. B, F, Living colonies surrounded by orange-colored coenosteum tissues. Scale bars = 10 mm. C, G, Calicular view showing a Pourtalès septal plan. Scale bars = 1 mm. D, H, Drawings of transverse thin sections. Note that individual corallites are connected with coenosteum skeletons. Scale bars = 3 mm.
Figure 2.
Schematic constructions of calicular features, and sympodial as well as monopodial forms of colonies.
A, Calicular view, showing the two opposite directive septa, the greater calicular diameter (GCD), and the lesser calicular diameter (LCD). Numbers indicate the cycles of septa; the first cycle of septa is circled. The two directive septa are indicated by black triangles, whereas the four remaining septa are shown by white triangles. B, Sympodial form of colony. TH indicates the corallum height, and LH the lateral corallum length. Note that the colony does not possess an axial corallite. C, Monopodial form of colony. D, Budding site of monopodial colony form, where offsets generally occur in some of the lateral primary septa.
Figure 3.
Measured parts of the lateral corallites of a colony.
A, Orientation of the directive septa, defined as the angle (φ) between a line connecting the two directive septa (solid line) and a horizontal line (dotted). B, Budding sites. The two directive septa are indicated by arrows, and the four lateral primary septa are indicated by white triangles. C, Inclination of budding, defined as the angle between the direction of the lateral corallites (solid line) and a horizontal line (dotted line) oriented perpendicular to the growth direction of the parent corallite (white dotted line).
Figure 4.
Results of regularities in budding (red triangles, directive septa; green triangles, the four lateral primary septa; red circles, budding site; 1, parent corallites; 2, daughter corallites; 3, grandchild corallites; arrows, growth direction).
A–F, Dendrophyllia boschmai (OCU 6654–6658). G–L, Dendrophyllia cribrosa (OCU 6664–6668). A–D and H–J, Orientations of directive septa. A–D, The directive septa of corallites, which are apparently perpendicular to the growth direction of the branch. Scale bars = 10 mm. A, Left-side view of the colony shown in C. B, Right-side view of the colony shown in C. C, Front view of the colony shown in A and B. D, Right-side view of the colony shown in G. H, The directive septa of corallites, which are apparently parallel to the growth direction of the branch. Scale bars = 5 mm. I, J, Actual relationships between directive septa of parent and its derived corallites. Scale bars = 5 mm. E, F, J, and L, Budding sites. Scale bars = 5 mm. The offsets ordinarily occur in either of the primary septum on one side of individual corallites, excluding the directive septum. G and M, Inclinations of budding. Scale bars = 10 mm.
Figure 5.
Rose diagrams showing the divergent budding angles between lateral corallites, their orientations and the inclination of the lateral corallites of Dendrophyllia boschmai (A, C) and Dendrophyllia cribrosa (B, D).
A–B, Orientations of directive septa. C, Inclinations of lateral corallites.
Figure 6.
Branching area and growth direction (red triangles, directive septa; green triangles, the four lateral primary septa; red circles, budding site; arrows, growth direction; 1, parent corallites; 2, daughter corallites; 3, grandchild corallites).
A–D, Dendrophyllia boschmai (OCU 6661). E–I, Dendrophyllia cribrosa (OCU 6671). Scale bars = 5 mm. A and E, Branching area of colony. B and F, Drawings of A and E, showing the branching area and budding sites. C, Front view. D, Drawing of C, showing the branching area and growth direction. G, Top view of the colony shown in the left side of E. H, A drawing of G, showing the sinistral growth direction. I, Top view of the colony shown in the right side of E. J, A drawing of I, showing the dextral growth direction.
Figure 7.
Schematic diagrams of spiral architecture in Dendrophyllia cribrosa (green arrows, growth direction of the colony; blue arrow, growth direction of a budding corallite).
A, One round of spiral architecture, which is made up of three individuals. The angle between a parent and its daughter corallites is approximately 120°. B, Growth directions of the individuals. C, Schematic view of the internal structure in D. cribrosa. D, Growth direction of the colony.
Figure 8.
Schematic diagrams of the budding modes and the polarity (red bars, directive septa; green bars, the four lateral primary septa; red circles, budding site; white circles, polarity; arrows, growth direction; white lines, plane of bilateral symmetry).
A–D, Dendrophyllia boschmai. E–H, Dendrophyllia cribrosa. A and E, Locations of budding sites and growth direction of individual corallites. x and y, dichotomous branching areas of a colony. B and F, Essential units of sympodial growth. C and G, Top views. D and H, Lateral views. Notably, given these regularities, D. boschmai grows in a zigzag fashion by budding at right and left sites alternatively, whereas D. cribrosa grows helically by budding at a particular site. In addition, D. cribrosa inevitably changes the direction of rotation in right and left branches after branching due to the presence of developmental constraints for maintaining polarity.