Conchocelichnus seilacheri igen. et isp nov., a Complex Microboring Trace of Bangialean Rhodophytes

Traces of microboring microbial endoliths (euendoliths) conform closely to the outlines of their makers as they are made. This habit evolved among prokaryotic cyanobacteria and eukaryotic rhodophytes, chlorophytes, and fungi. Among eukaryotic microborers, the endolithic mode of life is often limited to a phase in the course of their development, which alternates with an epilithic leafy phase. These endolithic phases are sometimes independently described as separate genera and species. This was the case with Conchocelis rosea Batters, 1891, later identified as the endolithic phase of Porphyra and Bangia that helped in identification of fossil bangialean rhodophytes of Silurian age: Palaeoconchocelis starmachii Campbell, Kazmierczak et Golubic, 1979. However, the traces of Conchocelis phases, although conspicuous and used to characterize the resident body fossil, were never formally described. We present here the formal ichnotaxonomic description of the complex and variable Conchocelis trace as Conchocelichnus seilacheri igen. et isp. nov., based primarily on Oligocene (Tertiary) borings in molluscan shells of Mainz Basin, Germany, while consulting similar fossil borings of the Silurian and Jurassic findings and compareing them with modern occurrences in nature and culture. With the new trace name Conchocelichnus seilacheri igen. et isp. nov., we honor the work of the renowned paleontologist and ichnologist, Prof. Dr. Dolf Seilacher.