Onisimus normani Sars 1891

• Main Authors: Vader, Wim, Johnsen, Jan Roger, Tandberg, Anne Helene S.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2020
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Malacostraca; Amphipoda; Uristidae; Onisimus; Onisimus normani; Andfjorden; Barents Sea; Greenland; Northern Norway
• Online Access: https://doi.org/10.5281/zenodo.5633966; http://treatment.plazi.org/id/03E316070048FFAD72A1FC0B4566A3D9

Key to the ‘ normani -group’ The ‘ normani -group’ within Onisimus is characterized by a partly cleft telson, a completely constricted uropod 2, and a peculiar 1 st epimeral plate, with an anterodistal hook (Vader et al . 2005). The group consists of O. normani , O. turgidus , and 2 or 3 taxa closely related to O. turgidus , but strongly deviating in the arrangement of the setal teeth on the outer plate of maxilla 1. Material belonging to these taxa has been found in the W Atlantic Ocean, near Greenland and in the NW Pacific (Johnsen 2001). Most (or possibly all) species in this group appear to be obligate associates of sea anemones, a trait absent in all other Onisimus species. In Norwegian waters there are two species in this group, O. normani in W Norway north to Andfjorden, and O. turgidus in N Norway and the Barents Sea. They can be distinguished as follows: 1. Pereopod 1 palm oblique, propodus subrectangular. Uropod 2 inner ramus with small setae in constriction; uropod 1 outer ramus without spines on inner margin. Onisimus normani Sars, 1891 – Pereopod 1 palm strongly oblique, propodus triangular. Uropod 2 inner ramus with large spine in constriction; uropod 1 outer ramus with spines on inner margin. Onisimus turgidus (Sars, 1879) Published as part of Vader, Wim, Johnsen, Jan Roger & Tandberg, Anne Helene S., 2020, Onisimus turgidus (Sars, 1879) (Amphipoda, Uristidae), an overlooked amphipod from sea anemones in Northern Norway, pp. 34-50 in European Journal of Taxonomy 724 on page 36, DOI:10.5852/ejt.2020.724.1155, http://zenodo.org/record/5627470