title: Two new species of poecilostomatoid copepods symbiotic on the venomous echinoid Toxopneustes pileolus (Lamarck) (Echinodermata) from Vietnam.
abstract: Two new coexisting species of crustacean copepods (Poecilostomatoida) belonging to the echinoid-specific genera Mecomerinx Humes, 1977 (Pseudanthessiidae) and Clavisodalis Humes, 1970 (Taeniacanthidae) found associated with the venomous flower urchin Toxopneustes pileolus (Lamarck) (Echinodermata: Echinoidea: Toxopneustidae) in the South China Sea (Vietnam) are described. The diagnostic features of Mecomerinx ohtsukai n. sp. are: (i) three setae and one aesthetasc on the first segment of antennules; (ii) relatively long caudal ramus; (iii) elongated terminal segment of the antenna; and (iv) two claws on the terminal segment of antenna slightly unequal in length. The taeniacanthid copepod Clavisodalis toxopneusti n. sp. is distinguished from all seven known congeners by having two-segmented endopod of the legs 2-4 and four setae on the distal endopodal segment of the leg 1. This is the first report on copepods associated with echinoids of the genus Toxopneustes Agassiz and the first finding of Mecomerinx as well as taeniacanthid copepods in the South China Sea associated with echinoids.
authors.affiliation: Fisheries Science Institute, Chonnam National University, Yeosu, 59626, Republic of Korea.
authors.forename: Balu Alagar
authors.initials: BA
authors.lastname: Venmathi Maran
authors.affiliation: Department of Biology, Gangneung-Wonju National University, Gangneung, 25457, Republic of Korea.
authors.forename: Il-Hoi
authors.initials: IH
authors.lastname: Kim
authors.affiliation: Laboratory of Ecology and Morphology of Marine Invertebrates, A.N. Severtzov Institute of Ecology & Evolution RAS, Leninsky pr. 33, Moscow, Russia, 119071.
authors.forename: Olga A
authors.initials: OA
authors.lastname: Bratova
authors.affiliation: Department of Invertebrate Zoology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russia, 119992. ivanenko.slava@gmail.com.
authors.forename: Viatcheslav N
authors.initials: VN
authors.lastname: Ivanenko
mesh_terms: D000818:Animals; D033342:Copepoda / Q000033:anatomy & histology / Q000145:classification*; D004447:Echinodermata / Q000469:parasitology*; D013045:Species Specificity; D014744:Vietnam