AUTHOR=Stępień Anna , Jóźwiak Piotr , Jakiel Aleksandra , Pełczyńska Alicja , Błażewicz Magdalena 

TITLE=Diversity of Pacific Agathotanais (Peracarida: Tanaidacea)

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 8 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.741536

DOI=10.3389/fmars.2021.741536

ISSN=2296-7745

ABSTRACT=Agathotanais is one of seven genera classified into the family Agathotanaidae. So far, twelve species have been described for the genus, seven of which are known from the Pacific. However, considering the present poor state of knowledge on deep-sea environments, a much higher number of Agathotanais species than currently known can be suspected. Among the studied material, collected from below 1000 m during five deep-sea expeditions in different parts of the Pacific Ocean, we identified eight species: two of them were already known to the science: A. hadalis Larsen 2007 and A. spinipoda Larsen, 1999; five species were identified as new to knowledge and their formal description is presented in the paper: A. frutosae n. sp. and A. paleroi n. sp. from the NW Pacific (the Sea of Okhotsk and Kuril-Kamchatka Trench), A. jani n. sp. and A. beatae n. sp. from the Central Pacific (Clarion-Clipperton Fracture Zone), and A. oharai n. sp. from Australian slope. The eighth Agathotanais species in the material was determined using a molecular approach, but it was represented by only one partially destroyed individual and could therefore not be formally described. It is thus presented as Agathotanais sp. abyss-1. The proportion of Agathotanais collected at the Sea of Okhotsk was the highest (22%), whereas the numbers were substantially lower for the Kuril-Kamchatka Trench, the Central and the Southern Pacific. Molecular analyses confirmed monophyly of Agathotanais and Paragathotanais and a close relationship between both genera. Moreover, a close relationship between the two Australian species (A. oharai n. sp. and Agathotanais sp. abyss-1) was revealed. As a result of our findings, the number of species known from the Pacific is increased from five to eleven, with the total number of species in this genus increasing from twelve to 17. An updated identification key for Agathotanais species is given.