Genetic connectivity and isotopic niches of alvinocaridid shrimps from chemosynthetic habitats in Aotearoa/New Zealand, with a new Alvinocaris species

Sous presse dans Marine Ecology Progress Series

Methou, P., Ogawa, N.O., Nomaki, H., Ohkouchi, N., Chen, C., Schnabel, K.

Chemosynthetic ecosystems off Aotearoa/New Zealand comprise both hydrothermal vents on the Kermadec Arc and methane seeps on the Hikurangi Margin which host rich communities of specialized fauna including 4 alvinocaridid shrimp species. The systematic positions of these New Zealand alvinocaridid shrimps have not been studied using genetic tools and little is known about their habitat use and feeding habits. Here, we re-evaluate the taxonomy of alvinocaridid shrimps from Aotearoa/New Zealand using genetic barcoding, as well as characterize their connectivity and isotopic niches across eight localities. We show the presence of a new species—Alvinocaris webberi sp. nov.—previously confused with A. longirostris. We also show that A. alexander and A. chelys are junior synonyms of A. dissimilis, revealing a high genetic connectivity across hydrothermal vents and methane seeps from Japan to Aotearoa/New Zealand, greatly extending its range. Finally, we find clear niche separation in co-occurring alvinocaridid shrimps, suggesting different diets and/or habitat use. Nevertheless, all species rely on chemosynthetic resources, regardless of the habitat depth, which ranges from 380 to 1650 m.