Onisimus normani Sars 1891
- Dataset
- Onisimus turgidus (Sars, 1879) (Amphipoda, Uristidae), an overlooked amphipod from sea anemones in Northern Norway
- Rank
- SPECIES
Classification
- kingdom
- Animalia
- phylum
- Arthropoda
- class
- Malacostraca
- order
- Amphipoda
- family
- Uristidae
- genus
- Onisimus
- species
- Onisimus normani
discussion
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: