Middle Ordovician – ?Late Ordovician
Foerstephyllum is an extinct genus of stationary epifaunal suspension feeders which have been interpreted to have hosted symbiotic algae in their tissues
Identification in Hand Sample:
- Characterized by tabulae and very short straight septa
- Pores are lacking
- Septal insertion random
- Corralum cerioid
- Polygonal tubes that increase by lateral budding
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- Foerstephyllum Bassler is a tabulate coral having a hemispherical or globose corallum composed of polygonal tubes that increase by lateral budding. Septa are short and inserted randomly. Mural pores are sparse. Tabulae are present. Representatives of Foerstephyllum, and Ordovician genus are present in Cincinnatian series rocks of Southwestern Ohio.
Treatise on Invertebrate Paleontology, Part F, 2 of 2 (1981):
- Corralum cerioid; increase lateral; common walls with dense median plane; septal insertion random; septa short, obtuse, subequal longitudinal ridges with spinose axial edges, ? (each a single series of contiguous subhorizontil trabeculae); mural pores ?absent or very sparse; tabulae horizontal, complete.
- – Jull (1976) described lateral increase in Foerstephyllumm, which he regards as a tabulate although admitting that the assignment to either the Rugosa or Tabulata is still somewhat uncertain. Hystero-ontogeny in Foerstephyllum, however, resembles that in rugose corals such as Favistina (see Fedorowsky & Jull, 1976) and Hexagonaria (see Jull, 1973) rather than that seen in tabulates. According to Jull (1976), the early septal arrangement in Foerstephyllum vacuum (Foerste) is similar to the septal development in rugose corals and pores are lacking. Consequently, I consider Foerstephyllum to be a rugose coral.
- – When viewed from the top of the corallum, the arrangement of the corallites and of the septa within the corallites closely resemble Foerstephyllum (Bassler, 1950). The number of septa, furthermore, corresponds with that given for Foerstephyllum. In describing the genus Bassler (1950, p. 269) notes, however, the presence of well-defined mature and immature regions; furthermore, he notes that the septa do not appear in the immature region.
- From it is derived also a new group of species here designated as Foerstephyllum, new genus, characterized by tabulae and very short straight septa, with Columnaria halli Nicholson as the genotype. From Foerstephyllum arises the genus Favistella Hall long considered a synonym of Conumnaria but marked by septa reaching nearly to the center.