2008/05/01 by Betty I. Roots · 1 voice
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · Earth and Planetary Sciences · #Echinoderm biology and ecology #Marine Invertebrate Physiology and Ecology #Marine Sponges and Natural Products
paper · doi:10.1017/s1740925x0900012x
openalex publication_date 2008/05/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/15
Current concepts of invertebrate phylogeny are reviewed. Annelida and Arthropoda, previously regarded as closely related, are now placed in separate clades. Myelin, a sheath of multiple layers of membranes around nerve axons, is found in members of the Annelida, Arthropoda and Chordata. The structure, composition and function of the sheaths in Annelida and Arthropoda are examined and evidence for the separate evolutionary origins of myelin in the three clades is presented. That myelin has arisen independently at least three times, namely in Annelids, Arthropodas and Chordates, provides a remarkable example of convergent evolution.