Heterocoeniidae Oppenheim, 1930

Family Heterocoeniidae Oppenheim, 1930 View in CoL Genus Heterocoenia Milne Edwards & Haime, 1848b

Type species. Lithodendron exiguum Michelin, 1847 , Santonian of France .

Diagnosis. Colonial massive, hemispherical, foliose, encrusting, ramose, plocoid, cerio-plocoid, (sub-) fasciculate; subphaceloid to reptoid when developments of coenosteum reduced. Budding extracalicular, extracalicular-marginal, and by septal division often dividing the corallite in three new ones (“trinity-arrangement” sensu Baron-Szabo, 2014). Corallites circular to elongate or irregularly polygonal in outline. Tey are directly united by their walls, or separated by extensive vesicular to dense coenosteum, or loosely connected by fragments of exotheca in form of traverses. Septa compact, arranged in various symmetries (e.g., trimerally, hexamerally, bilaterally, indistinct). One main septum, with remaining septa sometimes reduced to rudimentary spines. Costate zone present, weakly developed, or absent. Colony surface granulated or smooth. Columella, synapticulae, and paliform structures absent. Intertrabecular distance ranging between 60 and 120 µm in septa. Endothecal dissepiments thin, mainly tabulate to subtabulate, vesicular (often in peripheral and thecal areas). Exothecal dissepiments large vesicular. Wall often thick, possibly septothecal and paraseptothecal. Corallite wall tends to become more flaky, “bubbly” (cf. sclerenchymal deposits sensu Kołodziej, 1995, p. 4), and disintegrated during the process of budding.