I’m proud to be an author with my two Spanish colleagues, Consuelo Sendino and Juan Luis Suárez Andrés, of a paper just out in the latest issue of Palaeogeography, Palaeoclimatology, Palaeoecology (we call it “Palaeo-cubed”). I’ll let the abstract tell the story (with some embedded links):
“A new rugose coral–cystoporate bryozoan association is here described from the Devonian of NW Spain. This is the first evidence of intergrowths between Devonian rugose corals and bryozoans. In this case bryozoans provided a suitable substrate for the settlement of corals, which were subsequently encrusted by the bryozoans. The hypothesis of intergrowth between living organisms is supported by the absence of encrustation of the rugose coral calices by the cystoporates. We suggest that the association was specific and developed through chemical mediation. This symbiosis was facultative for the bryozoans but likely not for the corals. The association provided the bryozoan host with additional substrate for encrustation as well as protection from various predators, and it allowed the rugose corals to grow in a muddy environment and benefit from the feeding currents of the bryozoans.”
The above images show some of these specimens of corals intergrown with bryozoans. The caption from Figure 2: Intergrowth of fistuliporid bryozoans and rugose corals from the Aguión Formation of Asturias, NW Spain. A. General view of DGO12902. B. General view of MMAGE0033. C. Detail of the corallite, MMAGE0032. D. Magnified corallite of the right side, MMAGE0033.
This cartoon from the paper shows the process in which a coral larva (planula) lands on a living bryozoan, somehow survives the encounter, and then the coral grows together with the surrounding bryozoan colony. The fun part is sorting out the biological and evolutionary context of this relationship.
I thank my colleagues Consuelo and Juan for inviting me into this project. I learned a lot that will be applied to similar intergrowing situations in the fossil record.
Sendino, C., Suárez Andrés, J.L. and Wilson, M.A. 2019. A rugose coral – bryozoan association from the Lower Devonian of NW Spain. Palaeogeography, Palaeoclimatology, Palaeoecology 530: 271-280.