Dive into the sea: first molecular phylogenetic evidence of host expansion from terrestrial/freshwater to marine organisms in Mermithidae (Nematoda: Mermithida)

• Published in: Journal of helminthology Vol. 96; p. e33
• Main Authors: Kakui, K., Shimada, D.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.01.2022
• Subjects: Animals; Aquatic crustaceans; Aquatic Organisms; Body cavities; Crustaceans; Fresh Water; Freshwater; Freshwater organisms; Helminths; Hosts; Humans; Illustrations; Inland water environment; Marine crustaceans; Marine organisms; Mermithidae; Mermithoidea - anatomy & histology; Mermithoidea - genetics; Nematoda; Nematodes; Parasites; Phylogenetics; Phylogeny; Research Paper; rRNA 18S; Shellfish; Terrestrial environments; Worms; phylogeny; roundworm; Endoparasite; intermediate host
• ISSN: 0022-149X; 1475-2697
• DOI: 10.1017/S0022149X22000256

We report the first mermithid nematode found to be parasitic in a marine tanaidacean crustacean. Ten host tanaidaceans were collected from a depth of 52 m in Otsuchi Bay, Iwate, Japan, north-western Pacific, and identified as a species in the tanaidid genus Zeuxo Templeton, 1840. Nematodes occurred in the host's body cavity; in one case, at least two individuals inhabited a single host. We provide a brief description and illustrations of the morphology of the nematode. In a phylogenetic reconstruction based on the 18S ribosomal RNA gene, the nematode nested in a clade otherwise containing mermithids from terrestrial or freshwater hosts, showing an expansion in host utilization in Mermithidae Braun, 1883 from terrestrial/freshwater hosts to a marine organism.