Mironov A.N., Dilman A.B., Krylova E.M. 2013. Global distribution patterns of genera occurring in the Arctic Ocean deeper 2000 m // Invertebrate Zoology. Vol.10. No.1: 167–194 [in English].

P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences, Nakhimovsky Pr., 36, Moscow, 117997, Russia; e-mail: miron@ocean.ru

doi: 10.15298/invertzool.10.1.08

KEY WORDS: distribution patterns, genera, Arctic Ocean, abyssal, faunal submergence, faunal emergence.

ABSTRACT: A list of genera represented in the abyssal (>2000 m) of the Arctic Ocean was compiled for 8 classes (Scaphopoda, Bivalvia, Crinoidea, Echinoidea, Holothuroidea, Asteroidea, Ophiuroidea and Ascidiacea) and some orders from the classes Anthozoa, Maxillopoda and Malacostraca. This list includes 92 genera and 133 species. Species endemic to the Arctic Ocean comprise 51% whereas species endemic to the Arctic abyssal comprise 19%. Only two small genera are endemic to the Arctic Ocean. Genera with a worldwide distribution (60 genera or 65%) dominate the Arctic abyssal fauna. Most genera (55 or 60%) can be considered as deep-sea specialists, with half or more of the species in each genus occurring deeper than 2000 m. About one third of genera (37%) are known outside the Arctic in the hadal zone (>6000 m). The share of genera known from the hadal is probably higher in the Arctic abyssal than in the abyssal of other oceans. For many genera, the worldwide minimum or maximum of their depth ranges is found in the Arctic Ocean. Distribution patterns of genera suggest that many deep-sea Arctic species derive from their congeners distributed in geographically distant regions (primarily the Southern Ocean and the Indo-West Pacific). The deep-sea North Atlantic was the main transit region on the pathway to the Arctic. There is no firm evidence of the presence of derivatives of the pre-Pliocene deep-sea Arctic fauna in the modern Arctic fauna. Twelve genera (13%) with a worldwide distribution are recognized as the most reliable examples of the emergence of the abyssal fauna in the Arctic Ocean. Two genera (2%) are characterized by the following distribution and ecological patterns: (1) distribution is limited to the Northern Hemisphere, (2) wide bathymetrical range (from shelf to abyssal), (3) abyssal records only within the Arctic Ocean, and (4) very wide ranges of habitats. Arctic submergence of the shelf fauna to the abyssal zone is suggested for these genera. Some higher taxa, not considered in the present work in detail, may have a high share of genera with similar distribution patterns. For instance the share of genera having submerged from the Arctic shelf to the abyssal is about 25% in the abyssal Arctic amphipod fauna.

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